bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Plantago Species from Nutrient‐rich and Nutrient‐poor Conditions: Growth Response, ATPases and Lipids of the Roots, as Affected by the Level of Mineral Nutrition
Authors: KUIPER DAAN , KUIPER PIETER J. C.
Published: April 2006

Two groups of Plantago species, one of relatively nutrient‐rich habitats (Plantago major L., P. major L. ssp. pleiosperma Pilger and P. martrima L.) and the other of relatively nutrient poor habitats (P. lanceolata L., P. media L. and P. coronopus L.), were compared with respect to the response of the plants to alterations of the level of mineral nutrition. The comparison deals with growth response and root cell membrane functions (Ca2+ and Mg2+ stimulated ATPases and lipids). As far as these parameters are concerned species from relatively nutrientpoor habitats are not much affected by bringing the plants to high‐salt conditions, while the reverse was true for species from relatively nutrient‐rich habitats when transferred to low salt medium.
Action Spectra for in vivo and in vitro Conversions of Phycochrome b, a Reversibly Photochromic Pigment in a Blue‐Green Alga, and Its Separation from Other Pigments
Authors: BJÖRN G. S.
Published: April 2006

Phycochrome b, one of the reversibly photochromic pigments found in Tolypothrix distorta seems to exist in only two forms: Pb500 and Pb570. The pigment has been spectroscopically demonstrated in vivo. It has also been separated from other pigments. Two different methods for separation have been used: isoelectric focusing and gel filtration. Preparations of purified phycobilisomes contain phycochrome b.

The in vivo and in vitro absorption difference spectra were determined as well as action spectra for the conversions in vitro and in vivo of Pb500 to Pb570 and vice versa.

Transformation kinetics of phycochrome b show that the conversions in both directions are initially first‐order reactions.
Micromanipulation of Cyanelles and a Cyanobacterium into Higher Plant Cells
Authors: BRADLEY P. M.
Published: April 2006

A cyanobacterium (WPI‐I) and cyanelles of Glaucocystis nostochinearum Itz, have been introduced into epidermal cells of Allium cepa L. cv. Downing Yellow Globe bulb scales by microinjection. Uptake of cyanelles into protoplasts of Allium cepa and Daucus carota L. cv. Imperator 58 has also been induced with polyethylene glycol. Protoplasts were cultured until new cell walls were synthesized.
Dependence of the Post‐Illumination Burst of CO2 on Temperature, Light, CO2, and O2 Concentration in Wheat (Triticum aestivum)
Authors: DOEHLERT DOUGLAS C. , KU MAURICE S. B. , EDWARDS GERALD E.
Published: April 2006

The effect of environmental factors on the post‐illumination burst of CO2 (PIB) and O2 inhibition of apparent photosynthesis (APS) in wheat (Triticum aestivum L.) was studied in an open gas exchange system utilizing the mathematics of non‐steady‐state systems. Two components of inhibition by O2 are suggested: one is caused by photorespiration as measured from the maximum rate of the PIB, and the second is direct inhibition as taken as APS2%O2— (APSx%O2+ PIBx%O2) where X is the oxygen concentration.

A primary PIB which occurred from 16–28 s after the darkening of the foliage was attributed to photorespiration. No primary PIB was observed at 2% O2. At a CO2 concentration of 100 μ/1 in the atmosphere (about 2.5 μM based on leaf intercellular concentration) and at 30°C and 145 nE/cm2 nE/cm2·s, APS decreased curve‐linearly with increasing O2 and reached an O2 compensation point of 560 μM (48% by volume), above which there was a net loss of CO2 in the light. The PIB increased with increasing O2 and became saturated at about 500 μM O2 but decreased above 900 μM O2. Direct inhibition of photosynthesis by O2 increased with increasing O2 concentration.

Decreasing CO2 concentration had an effect on the magnitude of the PIB similar to that of increasing O2. At 30°C and 21% O2, the PIB increased with decreasing CO2 down to the CO2 compensation point (I) of 1.4 μM (47 μM/l). Below Γ, both PIB and CO2 evolution into the air in the light (at 21% O2) increased and then decreased at CO2 below 0.8 μM.

The ratio of the PIB to APS2% o O2 increased linearly with increasing O2/CO2 ratio where O2 was held constant at 21% and CO2 was varied from 1.4 to 8.5 μM, while direct inhibition of photosynthesis expressed as a proportion of APS2%O2 remained constant over this range. At low CO2 concentration photorespiration as estimated by the PIB is the major part of O2 photosynthesis, while at atmospheric CO2 levels, direct inhibition is the major component.

The PIB and APS at 2% and 21% O2 increased hyperbolically with increasing irradiance and all became light‐saturated at about 65 nE/cm2 s. The percentage total O2 inhibition of photosynthesis remained constant with increasing irradiance as did the relative contribution of direct O2 inhibition or photorespiration (PIB) to total O2 inhibition.

The PIB and APS at 21% O2 had similar temperature optima of 30°C when experimental conditions were adjusted to provide a constant internal O2/CO2 solubility ratio at varying temperatures. However, with a constant external CO2 concentration, the temperature optimum for the PIB shifted upward to 35°C while that for APS at 21% O2 remained at 30°C, which may be due to an increased O2/CO2 concentration in the leaf with increasing temperature.
Relationships between Motor Cell Ultrastructure and Leaf Movements in Samanea saman
Authors: MORSE MARY JANE , SATTER RUTH L.
Published: April 2006

We examined the fine structure of motor cells in the secondary pulvinus of Samanea saman (Jacq.) Merrill, to aid in analyzing the cellular basis for K+ and Cl− driven, turgor regulated circadian leaflet movements. Pulvini that were (a) open (horizontal) in the light, (b) closed (vertical) in the dark, or (c) at an intermediate angle after 96‐h incubation in H2O in darkness, were cut into cross sections, sub‐divided into quadrants, and prepared for electron microscopy by standard methods.

The walls of many cells are ridged, appearing scalloped in cross section, the plasmalemma following the wall contours. Plasmodesmata localized in pit fields are most numerous in the inner cortex of the extensor (abaxial), and least numerous in the outer cortex of the flexor (adaxial) (3.9 and 0.7, respectively, per μm2 wall area). Vacuole size, number of vacuoles per cell, and the condition of the electron dense precipitate within the vacuole also vary with cell location, multivacuolation being most pronounced in the outer cortex of the extensor. Chloroplasts are dimorphic: those in cells close to the vascular tissue are very large, circular in cross section, and contain huge starch deposits at all times, while those in the remainder of the cortex are smaller, usually oblong, and contain large starch deposits at the beginning of the dark period, but are devoid of starch at the beginning of the light period. However, both types of chloroplasts in excised pulvini incubated in H2O in darkness for 96 h still contain starch deposits, indicating that (1) light may promote starch degradation, or (2) starch degradation and resynthesis may be rhythmic.
Is the Diageotropic Tomato Ethylene Deficient?
Authors: JACKSON MICHAEL B.
Published: April 2006

The production of ethylene by a mutant form of tomato (Lycopersicon esculentum Mill. cv. Ailsa Craig) with diageotropic shoot growth was compared with that from non‐mutant, upright plants. No difference in the rate of production by segments of petiole or stem apex was observed. The amounts of ethylene produced by excised segments of petiole from diageotropic and upright plants in response to wounding were also comparable.

When the roots of either kind of plant were exposed to anaerobic conditions, the production of ethylene increased in the petioles; in ordinary plants this was associated with epinastic curvature, while in diageotropic plants the direction of shoot extension became reorientated from the horizontal to a more upright position. Exogenous ethylene gas had similar effects.

These results support the view that the mutant has a modified response mechanism to gravity and to ethylene rather than an abnormally slow rate of ethylene production in the shoot. Since applying inhibitors of ethylene action to non‐mutant, upright plants did not induce diageotropism, endogenous ethylene seems unlikely to play a significant role in maintaining their upright orientation.

The roots of both kinds of plant produced large amounts of ethylene, although the rate for diageotropic roots was about 37% less than that of roots from normal plants. Application of indol‐3‐ylacetic acid increased the production of ethylene by all roots but those from mutant plants were less responsive.
Influence of Abscisic Acid on Phosphorus Metabolism and Respiration in Potato Tuber Discs. Comparison with the Cycloheximide Effect
Authors: HOURMANT ANNICK , PENOT MICHEL
Published: April 2006

Ageing of discs of potato tuber by incubation in an aerated medium, produces an increase in the rates of respiration and of phosphate uptake. The presence of cycloheximide (CHM) or abscisic acid (ABA) in the uptake medium, does not change uptake by fresh tissue over 3–4 h. On the other hand, CHM causes an inhibition of the rate of uptake by aged tissue although ABA does not. The addition of CHM or ABA to the ageing medium, prevents totally (CHM) or only partially (ABA) the increase in phosphate uptake. The analysis of 32P‐incorporation into the various phosphorylated fractions after 24 h of ageing with CHM or ABA show that CHM induces a large inhibition of the rate of uptake with an almost complete inhibition of 32P‐incorporation into the various phosphorylated fractions. By contrast, ABA produces equal inhibition of 32P labelling of all fractions including all acid‐soluble components. CHM prevents the increase in the rate of respiration, whereas ABA causes a slight stimulation. In both cases, no important effect on ATP content was observed. These results are discussed in terms of a comparison of ABA and CHM actions. They lead to the hypothesis of a specific effect of ABA on the development of the uptake mechanism.
Ethylene Production by Tobacco (Nicotiana tabacum) Callus
Authors: HUXTER TERRY J. , REID DAVID M. , THORPE TREVOR A.
Published: April 2006

Tobacco callus cultures grown on defined agar‐solidified media produced ethylene in differing amounts, which were related to cultural treatment and age of the callus. There was a close correlation between the rate of ethylene production and growth. In darkness, maximal rates occurred in the third week of growth with ethylene production in the range of 750 nl (callus piece)−1 d−1 (fr. wt. = 1.5 g), and in the light, maximal rates occurred in the first week of growth, 200 nl (callus piece)−1 d−1 (fr. wt. = 200 mg). Growth was also correlated with ethylene production when the latter was altered by exposure of the callus to inhibitors of ethylene synthesis, L‐canaline, benzyl isothiocyanate, and 3,5‐diiodo‐4‐hydroxy‐benzoic acid. No correlation was found following treatment with AgNO3, a presumptive inhibitor of ethylene action. The inhibition of growth and ethylene production by L‐canaline was partially reversed by gassing the cultures with ethylene (1 μl/1). A mercuric perchlorate sink had no significant effect on growth. A possible relationship between ethylene evolution and growth is discussed.
The Effect of Some Protein and Non‐Protein Amino Acids on the Growth of Cladosporium herbarum and Trichothecium roseum
Authors: SIMOLA LIISA KAARINA , LÖNNROTH KAIJA
Published: April 2006

The effect of ten amino acids as the sole nitrogen source for the growth of Cladosporium herbarum (Link.) Fr. and Trichothecium roseum (Bull.) Link. was studied in order to clarify the fungus‐host plant relationship. Special attention was paid to some rare non‐protein amino acids of legumes. The best nitrogen sources for both fungi were γ‐aminobutyric acid, arginine, serine and proline. Cladosporium could use homoarginine and canavanine, but these two amino acids were not used by Trichothecium when each was given as the only nitrogen source. Both fungi utilized ornithine, homoserine and a,γ‐diaminobutyric acid to a limited extent. Pipecolic acid was not growth promoting. The growth‐retarding effects of rare non‐protein amino acids (homoarginine, canavanine, a,γ‐diaminobutyric acid and pipecolic acid) were usually reversed by higher concentrations of their normal analogues. It is possible that rare non‐protein amino acids may slightly protect the host plant against fungal infections, but there are clear differences between fungi in their reaction to non‐protein amino acids.
Growth Cycles in Lemna gibba Cultures and Their Effects on Growth Rate and Ultrastructure
Authors: TILLBERG E. , HOLMVALL M. , ERICSSON T.
Published: April 2006

A long‐established axenic culture of Lemna gibba G3 was maintained in exponential growth phase under controlled conditions. Weekly analyses for 2 years showed that the individual plants of the Lemna gibba clone fluctuated between two forms. One extreme consisted of plants light in weight, small in size, and with a high relative growth rate (RGR), the other of heavy, large, and more slowly growing plants. At intervals plants having intermediate characteristics dominated in the stock culture. Indication of an annual growth‐cycle was also found.

The magnitude of growth response (weight, RGR, area, and dry matter content) after treatment with abscisic acid (ABA), 6‐benzylaminopurine (BAP), and a combination of the two was different for low‐weight and heavy plants. The heavy plants were more sensitive to ABA and BAP treatment than the low‐weight ones. The accumulation of starch was least in small untreated plants and greatest in ABA treated plants. Large electron transparent globules were found in the chloroplasts of the ABA treated plants and in heavy plants regardless of how they had been treated.

The different physiological and ultrastructural characteristics of the two forms of Lemna plants probably reflect an ageing‐rejuvenation cycle. Emphasis is placed on the importance of this cycle when Lemna is used as a model plant in physiological experiments.
An Analysis of the Role of Potassium in the Growth Effects of Cytokinin, Light and Abscisic Acid on Cotyledon Expansion
Authors: GREEN JEROME F. , MUIR ROBERT M.
Published: April 2006

High external concentrations of potassium were found to promote light‐induced growth of cucumber cotyledons similarly to the effects previously observed for the growth induced by cytokinins. At 40 mM KCl, the response to white light was 3.6 times greater than in the absence of KCl. The promotive effect of calcium on the growth induced by cytokinin was not observed for light. In 40 mM KCl and 10 mM CaCl2, the responses to light and cytokinin were similar and additive. Both near‐red and far‐red light induced growth at low intensities. The response to white light at low intensities was sharply increased with higher intensity up to 24 μE m‐2 s‐1 and only slightly increased above that level.

Abscisic acid was found to inhibit strongly the responses to light and cytokinin. The inhibition was greater in the presence of KCl than in its absence and thus abscisic acid appeared to inhibit primarily by its interference with potassium uptake. Kinetic analysis found the light response promoted by potassium to be inhibited competitively by abscisic acid, with the light response having a Km of 34 mM KCl and a Vmax of 115 mg/cotyledon × 4 days. The inhibition of the cytokinin response by abscisic acid was noncompetitive in relation to potassium, having a Km of 1 mM KCl and a Vmax of 50 mg/cotyledon × 4 days.

It is suggested that cytokinin, light and abscisic acid have primary properties affecting membrane permeability and that their interaction with potassium is an explanation of many similarities between light and cytokinin responses and their inhibition by abscisic acid.
Starch Synthesis in Developing Potato Tubers
Authors: HAWKER J. S. , MARSCHNER H. , KRAUSS A.
Published: April 2006

The activities of enzymes involved in starch metabolism were measured at intervals during tuberization and the early stages of tuber growth in Solanum tubersum grown in water culture under controlled environmental conditions. Starch synthase, ADPglucose pyrophosphorylase, UDPglucose pyrophosphorylase and phosphorylase activities all increased during tuber development, the most pronounced increases occurring in the activities of ADP‐glucose pyrophosphorylase and phosphorylase. The activity ratio ADPglucose pyrophosphorylase/phosphorylase was lowest in slow growing tubers and hightest in fast growing tubers. In addition, high sugar concentrations in fast growing tubers and low sugar concentrations in slow growing tubers suggested that enzyme levels might be influenced by sugar concentration. The activities of starch synthase, phosphorylase and ADPglucose pyrophosphorylase were increased 2–2.5 fold by the presence of 100 mM K+. It is concluded that the major enzyme changes occur as a consequence of tuber initiation and that starch accumulation is controlled, at least in part, by the activities of ADPglucose pyrophosphorylase and phosphorylase.
A Definition of Optimum Nutrient Requirements in Birch Seedlings
Authors: INGESTAD TORSTEN
Published: April 2006

Birch seedlings (Betula verrucosa Enrh.) were grown in nutrient solutions with pH varied in the range 2.5 to 6.8 or temperature varied in the range 2.5 to 35°C. The criteria for maximum growth previously established for birch seedlings were used and maintained by means of automatic pH and conductivity titrations with stock solutions containing the optimum nutrient proportions. Both nitrogen sources, NH4 and NO3, were present in the solutions. Growth rate was maximum or close to maximum between pH 4.0 and 6.8, whether kept at a specific level or allowed to vary between the extremes. At pH 3.5 and lower, the calcium uptake was decreased and root damage was observed. The seedlings has also a high dry matter content and obviously an unsatisfactory water balance. pH 2.5 was rapidly lethal. Growth rate was linearly correlated with solution temperature up to 20°C. Temperatures above 30°C, especially in the range 32.5 to 35°C, resulted in rapid decrease in growth rate. The nutrient contents in the seedlings were strongly affected by solution temperature in the low as well as in the high range when expressed on a dry weight basis. However, this effect was almost entirely attributable to changes in dry matter content. When expressed on a fresh weight basis, nutrient uptake and nutrient status of the seedlings appeared to be optimum throughout, although a variation remained since the varying dry matter content is included in the fresh weight basis. The results indicate, in agreement with the literature, that disturbed water uptake and water balance is the way in which growth is affected by root medium temperature. Similarly, extremely low pH levels in the nutrient solution meant root damage, although birch seedlings appear comparatively insensitive to pH variations. Thus, the growth technique used supplied the seedlings with adequate nutrients, so that the criteria used in the definition of nutrient requirements in birch seedlings are valid within wide ranges of solution pH and temperature; and other factors than nutrition determine growth.
Alterations in Endogenous Levels of Gibberellin‐like Substances during Germination of Phaseolus vulgaris Seeds
Authors: VON SCHIRACH‐SZMIGIEL LINDA
Published: April 2006

The endogenous gibberellin‐like substances were determined in mature dry and germinating bean seeds, Phaseolus vulgaris L. cv. Alabaster. Methanol extracts were partitioned against ethyl acetate and butanol at neutral and acid pH. Each phase was individually chromatographed on a silica gel column. The gibberellin activity was measured with the Tan‐ginbozu dwarf rice micro‐drop bioassay. Each extract was tested in two dilutions. Extracts from dry seeds showed the highest gibberellin activity, largely attributable to ethyl acetate‐soluble substances. The activity was considerably reduced in extracts from seeds imbibed for 1 day. Gibberellin‐like substances soluble in butanol appeared in extracts from seeds soaked for 1 or more days.
Zinc Effects on Growth, Pigmentation and Antibacterial Activity of Monascus purpureus
Authors: BAU YUN‐SUN , WONG HIN‐CHUNG
Published: April 2006

Growth, pigmentation and antibacterial activity of Monascus purpureus Went (starch fungus) were affected by zinc. Zinc at concentrations of 2 × 10‐3M and 3 × 10‐3M nearly stopped the growth, pigmentation and antibiotic production of both wild type and strain NI IS in liquid medium. Relatively vigorous growth, high pigment production, and strong antibacterial activity of NIIS still occurred on solid medium with the same zinc concentrations. Wild type was hardly affected by zinc concentrations lower than 2 × 10‐3M. The growth of strain NI IS was significantly inhibited even by 5 × 10‐5M zinc, but pigment production and antibacterial activity were highly promoted by 5 × 10‐5M zinc. Increase of glucose concentration also promoted pigment and antibiotic productions of strain NI IS. Glucose effects were intensified as 1 × 10‐3M zinc was added. Zinc may act as a growth inhibitor and concomitantly as a stimulant for glucose uptake and for the synthesis of metabolites such as pigments and antibiotics.
Phytochrome Pelletability in Barley
Authors: ROTH‐BEJERANO NURIT , KENDRICK RICHARD E.
Published: April 2006

Phytochrome pelletability in the 1000 g and 20,000 g pellet from crude homogenates of etiolated Hordeum vulgare L. cv. Ark Royal primary leaves is enhanced by red light in vivo and in vitro. Red enhanced phytochrome pelletability appears different in the 1000 g and 20,000 g pellets after red light in vivo, being irreversible by subsequent far red light in the latter. Mg2+ concentration in the range 1–20 mM has no effect on red enhanced phytochrome pelletability. The enhancement of pelletability is reduced by low pH and high 2‐mercaptoethanol concentration, conditions which lead to a high level of pelletability of the far red absorbing form of phytochrome. Washing these pellets at high pH or low 2‐mercaptoethanol concentration reveals the red enhancement of pelletability. The results are discussed in terms of a possible two point attachment of phytochrome to membranes.
Fatty Acid Synthesis in Hydrilla Chloroplasts
Authors: BHATIA I. S. , AHUJA K. L. , SUKHIJA P. S.
Published: April 2006

The rates of carboxylation, photophosphorylation and acetate incorporation have been compared in the intact and broken chloroplasts of Hydrilla verticillata Royle leaves in the presence and absence of certain inhibitors and metabolites. The intact chloroplasts showed low rates of photophosphorylation, high rates of carboxylation, and exhibited normal capacity for fatty acid biosynthesis. In broken chloroplasts a drastic decrease was observed in the rates of carboxylation and acetate incorporation. However, the rate of photophosphorylation was considerably increased. In the presence of light, inhibitors such as iodoacetamide, arsenite and sodium azide decreased the photophosphorylation rate. F‐1,6‐di‐P and PGA stimulated CO2 fixation rate. In the absence of artificial light, inhibitors such as sodium arsenite, gluconate‐6‐phosphate, sodium azide and iodoacetamide decreased the rate of CO2 fixation. CoA, ATP, G‐6‐P, F‐1,6‐di‐P Stimulated the synthesis of fatty acids. Exogenous supply of ADP. NADH, NADP and NADPH did not stimulate fatty acid biosynthesis probably because these compounds could not gain entry into the chloroplasts. Light was necessary for the in vitro fatty acid biosynthesis.
Distribution of Soluble 14C‐Labelled Assimilates as Related to Distribution of 14C‐Benzyladenine in Shoot Tips of Hedera helix
Authors: CLARK JAMES R. , HACKETT WESLEY P.
Published: April 2006

The relationship between benzyladenine and assimilate distributions in shoot tips of English Ivy (Hedera helix L.) was studied. Exogenous applications of benzyladenine resulted in small amounts of the hormone moving to the apical meristem. The large part of the recovered benzyladenine was found in the young leaves of the shoot tip.

Benzyladenine increased the amount of 14C‐labelled assimilates in the shoot tip, but the distribution pattern of those assimilates within the tip was like that of the untreated control.
Oxygen Consumption Stimulated by δ‐Aminolevulinic Acid in Darkness and during Irradiation of Dark Grown Wheat Leaves
Authors: CARLSSON ROLF , SUNDQVIST CHRISTER
Published: April 2006

Dark grown wheat leaves (Triticum aestivum L. cv. Starke II Weibull), treated with δ‐aminolevulinic acid in darkness, showed an increased oxygen uptake as measured by a Warburg method. The production of CO2 was also increased in darkness, giving an RQ ≅ 1. The increased respiration was dependent on the treatment time as well as on the concentration of the δ‐aminolevulinic acid. Potassium cyanide suppressed both the normal and the increased respiration. The treatment with δ‐aminolevulinic acid caused accumulation of high amounts of protochlorophyllide. Levulinic acid suppressed the increased oxygen uptake as well as the protochlorophyllide accumulation in δ‐aminolevulinic acid treated leaves. Irradiation rapidly decreased the protochlorophyllide content with a simultaneous increase in oxygen uptake over the dark value. The peak value of the increase in oxygen uptake was reached after about 5 min. The light induced oxygen uptake was dependent on the amount of PChlide present at the onset of irradiation. Also the CO2 production was increased during the first minutes of irradiation but soon fell under the buffer control value. Neither potassium cyanide nor heat denaturation affected the oxygen uptake in light in contrast to the effect on the CO2 production, which was blocked by heat denaturation. The increased oxygen uptake in light initially seems to be a purely photochemical process leading to a release of CO2, which release is probably an enzymatic process induced by the photo‐oxidative decomposition of pigment.
Influence of Cycloheximide and Actinomycin D on Initiation and Early Development of Adventitious Roots
Authors: OPPENOORTH J. M.
Published: April 2006

From leaf cuttings of the bean Phaseolus vulgaris L. adventitious roots form on the petiole. This root formation is stimulated by treatment with auxin. Simultaneous or subsequent application of cycloheximide irreversibly inhibited dedifferentiation, so that root production was completely prevented. The effects of actinomycin D application depended upon the stage of development of the root primordium. Cells in the first stage of dedifferentiation were extremely sensitive. When actinomycin D was applied later than 6 h after cutting, its inhibiting effect gradually diminished.

It is concluded that an actinomycin D‐sensitive process occurring early in dedifferentiation is crucial for root initiation. A second, less actinomycin D‐sensitive process occurring later in dedifferentiation is required for the further development of the root primordium. During the initiation and development of the root primordium protein synthesis is required.
Starch Measurement in Plant Tissue Using Enzymatic Hydrolysis
Authors: HAISSIG BRUCE E. , DICKSON RICHARD E.
Published: April 2006

This work explored completeness of starch hydrolysis in situ in relation to degree of gelatinization, starch content of tissue, evailable enzyme activity, and time allowed for hydrolysis. Maximum hydrolysis of starch in lyophilized red oak (Quercus rubra L.) root tissue with purified Diazyme (amyloglucosidase) or Clarase (Takadiastase) required high enzyme activity (2.4 U Diazyme or 48 U Clarase per mg starch). Results suggested that at least 70 U Clarase or 5 U Diazyme should be used per mg starch in routine analyses. Neither prolonging gelatinization (more than 15 min) nor hydrolysis (more than 24 to 48 lh) offset inadequate starch hydrolysis caused by insufficient enzyme activity. Starch was completely hydrolyzed in situ after 48 h without gelatinization by 5 U of Diazyme per mg starch. Tissue weight (5 to 100 mg) had no effect on starch hydrolysis by sufficient enzyme. Methanol: chloroform: water (12:5:3 by volume) freed tissues of solubles before starch hydrolysis. No interference with the glucose oxidase analysis of hydrolysates was encountered. In addition, the pigment free methanol–water fractions (soluble sugars, amino acids, organic acids) and chloroform fractions (lipids and pigments) were available or further analysis. Results obtained with red oak were verified with issue from other species such as jack pine (Pinus banksiana lamb.) and white spruce (Picea glauca (Moench) Voss). The resulting technique simply and reliably measured less than 5% starch in 5 mg lyophilized tissue, with a minimum of sample manipulation.
Hormonal Modulation of the Oscillatory System Involved in Polar Transport of Auxin
Authors: WODZICKI TOMASZ J. , WODZICKI ALINA B. , ZAJACZKOWSKI STEFAN
Published: April 2006

The amount of natural auxin collected in agar as a result of basipetal efflux from the cambial region of successive short sections of pine stem varies so that a wave‐like pattern is formed. The wave‐length is several times longer than the cell length in the cambial region, suggesting the existence of a supracellular oscillatory system, which forms a morphogenic field in the stem tissues, The amplitude of the auxin wave is amplified by apical application of IAA to the longer stem sections, particularly at she time of spring initiation of cambial activity. The wave of auxin disappears after simultaneous apical application of IAA and ABA. The modulatory effects of IAA and ABA are translocated along the investigated stem sections faster than known transport velocities of IAA molecules. This fact is considered as evidence of apical control of the morphogenic field by way of influence upon a supracellular system of conjugated oscillators in the tissue.
A System Approach to Fluorescence Induction in Green Leaves
Authors: KLOCKARE BIRGITTA , BERNT MELØ THOR ,   with the participation of, JOHNSSON ANDERS
Published: April 2006

Intact green oat leaves (Avena saliva) were irradiated with modulated exciting light. Ai the application of initial square pulses of exciting light, the fluorescence induction pattern will change, but after some repeated pulses the fluorescence response pattern stabilizes and becomes identical. This periodic stimulation gave a better resolution of the two peaks constituting the fast fluorescence transient (the DPS region) compared to a single light pulse. The first peak could be depressed by weak light of wavelengths up to about 740 nm, given between the intense light phases of the pulse, while this treatment did not alter the second peak. The intensity of the higher light level of the pulse as well as the frequency were systematically varied. The results are tentatively rationalized in the form of sequential relaxation processes within the frame of the Hill‐Bendull scheme, leading to the possibility of two substances, one belonging to Photosystem II and the other to Photosystem I. underlying the two peaks in the DPS region of the fluorescence induction curve.
Acide abscissique lié et dormance embryonnaire chez Pyrus malus
Authors: LE PAGE‐DEGIVRY M. Th. , BULARD C.
Published: April 2006

Bound abscisic acid and embryo dormancy in Pyrus malus.

The first part of this work was devoted to the study of the behaviour of Pyrus malus L. cv. Golden Delicious embryos cultivated in vitro. At the beginning of the experiment, either the root (RM) or the distal part of the cotyledons (CM) was immersed in the medium. For embryos directly isolated from the fruits at harvest time, as well as for embryos submitted to a 3‐month post‐maturation treatment at 4°C, the dormancy was deeper in CM cultures than in RM. The use of gibberellins (GA4 or GA7) emphasized these differences.

The second part of this work was devoted to the study of free and bound forms of ABA (cis and trans isomers) in embryos isolated from the fruits at harvest time and cultivated by the RM or CM procedure during 3 weeks. The biochemical data obtained indicated in both cases the existence of the following three processes: (A) Mobilization of the bound ABA with the consequent release of free ABA; this was particularly important in CM. (B) Metabolism of free ABA: the isomerization into trans‐ABA only partly accounted for the decrease in the content of free ABA which was much greater in RM than in CM. (C) Transport of ABA towards the root, the result being an accumulation of free ABA in the root, much greater in CM than in RM; this would account for the deeper dormancy in CM than in RM.
Bromine, Bromophenols and Floridorubin in the Red Alga Lenormandia prolifera
Authors: PEDERSÉN MARIANNE , SAENGER PETER , ROWAN KINGSLEY S. , HOFSTEN ANGELICA V.
Published: April 2006

The pigment floridorunin was localized to the cuticle of the red alga Lenormandia prolifera (C. Ag.) J. Agardh by x‐ray micro‐analysis in Ihe transmission electron microscope and by its colour reactions in the light microscope. The pigment was set free from the cell wall by a pectinase. Bromine was also identified in the chloro‐plasts. the middle lamellae, the intercellulars and the pore plugs of the alga. The content of bromophenols in the alga increases with increasing age. The cell walls of old plants are stratified and their outer parts are apparently shed. The bromophenols could have a function as regulators of the epiphytes or the shedding of parts of the outer cell wall.
Distribution of Sodium and Chloride in Leaves of Suaeda monoica
Authors: ESHEL A. , WAISEL Y.
Published: April 2006

A modified electron probe was used for the determination of the distribution of Na and Cl in cross sections of Suaeda monoica leaves. The results were corrected for differences in local mass values along the analysis line and expressed as percentage of the ions in the dried tissue. Sodium was found lo be selectively accumulated in the outer layer of chlorenchyma, whereas Cl was concentrated mostly in the cells of the inner chlorenchyma. Considerable pan of the osmotic potential of these cells is thus ascribed to the presence of those ions.
Comparison of Compartmental Analysis for Rb+ and Na+ in Low‐ and High‐Salt Barley Roots
Authors: BANGE G.
Published: April 2006

The size of the cytoplasmic pools of Rb+ and Na+ in roots of barley (Hordeum vulgare L.) was estimated by two independent methods:

. from the time curves of net Rb+ and Na+ uptake in low‐salt roots;

. from the kinetics of ion exchange in Rb+‐and Na+‐saturated roots.

The results indicate that in low‐salt roots there is a lag‐phase in vacuolar accumulation of Rb+ but probably not of Na+. At the same time part of the cytoplasmic Na+ pool seems to be excluded from rapid exchange. Both for Rb+ and Na+, flux reduction in saturated tissue appears to be more pronounced at the tonoplast than at the plasmalemma.
Abscisic Acid‐like Inhibitors and Cytokinins during After‐ripening of Dormant Peanut Seeds (Arachis hypogaea)
Authors: NARASIMHAREDDY S. B. , SWAMY P. M.
Published: April 2006

Changes in abscisic acid‐like inhibitors and cytokinins were studied during dry storage after ripening of dormant peanut seeds. Decrease in ABA‐like inhibitors and increase in cytokinin levels was found as the seeds lose their dormancy. Dormancy of peanut seeds is associated with presence of a high level of ABA‐like inhibitors and a low level of cytokinins.
Efficiency of Root Respiration in Relation to Growth Rate, Morphology and Soil Composition
Authors: LAMBERS HANS
Published: April 2006

Root growth respiration and root maintenance respiration rate of the following species were determined: Hypochaeris radicata L. ssp. radicata L., H. radicata ssp. ericetorum Van Soest, Plantago lanceolata L., P. major L. ssp. major, P. major ssp. pleiosperma Pilgcr, P. maritime L., Senecio viscosus L., S. vulgaris L. and Urtica dioica L. A high root growth respiration (i.e. the amount of oxygen consumed for synthesis of a given weight of root material) implied a high maintenance respiration rate (i.e. the amount of oxygen consumed per unit of time and dry weight, but not connected with growth). High values of both components reflect a low efficiency of root respiratory processes.

The efficiency of root respiration, as determined by the values for root growth respiration and root maintenance respiration rate could not be demonstrated to be of advantage in adaptation to soil conditions, as e.g. nitrogen content, moisture content and pH. It is concluded that (he degree of ‘wasteful utilization of sugars’ in roots, i.e. such consumption of sugars as cannot be related to structural growth, storage of carbohydrates or maintenance processes, depends on imbalance of transport of sugars from the shoot to the roots with utilization of sugars for synthesis of root material.

The results are discussed in relation to Brouwer's explanation for the equilibrium between the growth of shoots and of roots. Root growth rate in the present species appears limited by a factor produced in the shoot under light conditions, and which factor is distinct from carbohydrates. The evidence presented shows that relatively inefficient root respiration does not imply a low growth rate. In regulation of plant growth the growth rate itself and also the shoot to‐root ratio may be more important than the regulation of the efficiency of energy metabolism.
Capacité caulogène de cellules de cal issues des couches cellulaires minces de type épidermique de ramifications florales de Nicotiana tabacum cv. Wise. 38 Par
Authors: HA NGOC K. A. , VAN TRAN THANH M.
Published: April 2006

Bud formation capacity of callus formed from thin epidermal cell loyers excised from floral branches of Nicotiana tabacum cv. Wise. 38.

Subepidermal cells of thin tissue pieces with a few cell layers were capable of forming eitber buds, roots, (lowers or non‐organ ogenetic callus. To determine wheiher this calltjs is able to dirferentiate into organs, we transferred it to media inducing eitber flowers, or buds, or roots. In this paper, we study ibe capacity of lbe callus to form buds. In 50% of the cases, the explants (being maintained for I day to 2 years in callus media) can still express the capacity to form buds. This percentage increased with increased agar concentration of the culture media. At the histological level, non‐organogenetic callus is characterized by the absence of tracheid differentiation, whereas in the organogenetic callus, iracheids were induced after their transfer into a ‘Bud medium’ and indicate an organogenetic differentiation pattern.
Effect of Auxin and Cytokinin on Newly Synthesized Proteins of Cultured Douglas Fir Cytoledons
Authors: HASEGAWA PAUL M. , YASUDA TAKESHI , CHENG TSAI‐YING
Published: April 2006

Newly synthetized cyloplasmic proteins of Douglas fir cotyledon culture capable of initiating adventitious bud formation (bud culture) were compared with those of morphologically distinct types of cultures, bud‐callus culture (some adventitious buds with callus), and callus culture (no adventitious buds; only callus). SDS polyacrylamide gel electrophoretic profiles of double labeled (14C‐and 3H‐) proteins showed that a persistent increase of low molecular weight proteins (16,000 to 20,000 daltons) was associated with bud culture. Similar electrophoretic profiles of proteins extracted in the absence and in the presence of protease inhibitor (4‐mcthylbenzene sulfonyl fluoride) or phenolic compounds absorbents (Dowex I‐X8 and polyvinylpolypyrolidine) were obtained indicating that the detected low molecular weights of these proteins represented the real monomeric state of these molecules.
Alternating Perturbation Response of the Water Regulatory System in Arena Leaves
Authors: JOHNSSON A. , SKAAR H.
Published: April 2006

The transpiration response of excised primary Avena leaves was studied when pulse perturbations were given to the water regulatory system. Repeated light pulses given to the leaf caused regularly alternating transpiration responses, i.e. the magnitude alternated regularly between a high and a low value. This effect, denoted alternating pulse response, could be recorded under quite different light pulse conditions but was not found when the pulse interval was too long or too short (longer than about 60 min. shorter than about 15 min). Sodium chloride given to the transpiration stream induced and increased the effect. Alternating pulse response could also be recorded when mannitol pulses were given to the root system of intact plants.
Conditions for rooting of leafy cuttings of Alnus incana
Authors: HUSS‐DANELL KERSTIN , ELIASSON LENNART , ÖHBERG INGEGERD
Published: April 2006

The rooting of softwood cuttings of Alnus incana (L.) Moench in nutrient solution was studied under controlled conditions. Cuttings consisting of one internode with the leaf and axillary bud attached rooted easily and more rapidly than shoot tip cuttings. Light was necessary for rooting but good rooting was obtained in photon flux densities of both 40 and 190 μmol m‐2s‐1. Root number and root length was reduced when light reached the base of the cuttings. Treatment with indolebutyric acid (10‐6–10‐4M) increased the number of roots but 10‐4M delayed rooting and decreased the root length. Debudded internode cuttings rooted as well as intact cuttings, and detached leaves also contained sufficient substances for rooting.
Hardiness dependent accumulation of phospholipids in leaves of wheat cultivars
Authors: HORVÁTH I. , VIGH L. , BELEA A. , FARKAS T.
Published: April 2006

Phospholipid content and composition in the leaves of thirteen cultivars of wheat differing in frost hardiness, were compared before and after hardening in order to see whether phospholipids play a role in surviving at low temperatures. The content of phospholipids in the leaves at the end of the hardening could be related to the aquired hardiness, and the relationship between the two phenomena could be described by the regression equation y = (0.174 ± 0.0016) x + 1311. Accumulation of phospholipids represents a hardiness dependent augmentation of membranes. Phosphatidylcholine appeared to be preferentially accumulated in hardy cultivars during the hardening process. As there are no significant differences in phospholipid fatty acid compositions investigated earlier, these results suggest the importance of the polar head group composition of membranes in avoiding frost injury.
Flower bud differentiation in Salix pentandra as affected by photoperiod, temperature and growth regulators
Authors: JUNTTILA OLAVI
Published: April 2006

Flower bud initiation in seedlings and vegetatively propagated plants of Salix pentandra from different locations has been studied under controlled conditions. In mature plants flower bud formation was induced by 2‐chloroethyltrimethylammoniumchloride (CCC) and by short day treatment. The effect of CCC was antagonized by GA3. The critical photoperiod for flower bud formation was about 18 h for a southern clone (from 49°48'N), but cuttings of a northern ecotype (from 69°39'N) formed flower buds even at 24 h photoperiod. Generally, flower bud formation occurred simultaneously with apical growth cessation. However, apical growth cessation was not a prerequisite for floral initiation and flower buds were also found in elongating plants. Seedlings up to 60 days old did not form flower buds in growth chamber studies. The length of the juvenile phase has not been studied in detail, but cuttings taken from seedlings approximately 20 cm high and 60 days old were able to develop flower buds when treated with CCC. A gradual transition from the juvenile to the mature phase was obtained by repeated pruning of seedlings grown at 18°C and 24 h photoperiod.
Two temperature‐sensitive photosystem II mutants of pea
Authors: STUMMANN B. M. , VEIERSKOV B. , JACOBSEN S.‐E. , HENNINGSEN K. W.
Published: April 2006

Two nuclear gene mutants of pea, chlorotica‐887 and chlorina‐5756, are temperature‐sensitive in the development of photosystem II activity. Low temperature flourescence emission spectra of leaves show that the peak at 697 nm from the reaction center of photosystem II is present when the mutants have been grown at 18°C, but absent when they have been grown at 30°C. For leaves of chlorina‐5756 grown at 18°C the relative size of the peak at 697 nm is reduced compared to that of leaves of the wild type or chlorotica‐887 grown at this temperature. Flourescence induction curves of leaves from wild type plants and chlorotica‐887 grown at 18°C possess two steps, while those of leaves from chlorina‐5756 grown at 18°C or 30°C and chlorotica‐887 grown at 30°C show at fast rise to the maximal level of fluorescence. Measurements on chloroplasts isolated from the mutants indicated that the photosystem I activity per g leaf material is comparable for plants grown at 18°C and plants grown at 30°C. In contrast, no photosystem II activity was detected when the mutants had been grown at 30°C. It is suggested that these mutants are affected in a component required for the assembly of functional photosystem II complexes.
Photosynthate partitioning into leaf starch as affected by daily photosynthetic period duration in six species
Authors: CHATTERTON N. JERRY , SILVIUS JOHN E.
Published: April 2006

Starch accumulation rates increased up to five‐fold in the leaves of five out of six species examined when plants were shifted from a long (12 or 14‐h) to a short (7‐h) photosynthetic period. The five species that responded were corn (Zea mays L.), pangola (Digitaria decumbens Stent.), soybean (Glycine max L.) Merr.), spinach (Spinacia oleracea L.), and sugarbeet (Beet vulgaris L.) However, the rate of starch accumulation in alfalfa (Medicago sativa L.) was unaltered following a shift from a long to a short photosynthetic period. We conclude that photosynthate partitioning into chloroplast starch, at least in a wide variety of species, is a programmable process that can be manipulated by altering the length of the daily photosynthetic period.
Metabolism of diclofop‐methyl (methyl‐2‐[4‐(2′,4′‐dichlorophenoxy)phenoxy] propanoate) in cell suspensions of diploid wheat (Triticum monococcum)
Authors: DUSKY J. A. , DAVIS D. G. , SHIMABUKURO R. H.
Published: April 2006

The metabolism of the herbicide, diclofop‐methyl (methyl‐2‐[4‐(2′,4′‐dichlorophenoxy)phenoxy]propanoate, in cell suspensions of resistant diploid wheat (Triticum monococcum L.) was determined 1, 8, and 24 h after treatment with 14C‐diclofop‐methyl. The 14C‐labeled products were identified by thin layer chromatographic comparisons to appropriate standards. Eight hours after treatment with 5 μM diclofop‐methyl in 0.8% acetone (neither of which were toxic to the cell suspensions) 87.2% (84.0% methanol soluble, 3.2% methanol insoluble) of the total 14C recovered (90.4%) was in the cells and 12.8% was in the medium. Major metabolites found in methanol extracts of the cells were diclofop (2‐[4‐(2′,4′‐dichlorophenoxy)phenoxylpropionic acid), diclofop hydroxylated at an undetermined position on the 2,4‐dichlorophenyl ring (ring‐OH diclofop), and conjugates of ring‐OH diclofop. Acid hydrolysis of the conjugated metabolite(s) yielded ring‐OH diclofop and diclofop. Twenty‐four hours after treatment 70–75% of the total 14C recovered was present as conjugated metabolites. With the exception of ring‐OH diclofop, all metabolites present in the cells were also recovered from the medium. A metabolite found in low concentrations in the medium that yielded diclofop upon hydrolysis was identified as an ester conjugate. Toxic concentrations of diclofop‐methyl (10 and 20μM) had no effect on the metabolism of the herbicide, although the rate of uptake was slower than for cells treated with 5 μM herbicide. The products of diclofop‐methyl metabolism in cell suspensions of T. monococcum were compared to previous data from T. aestivum intact plant metabolism of diclofop‐methyl.