bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Water Balance of Cut Rose Flowers
Authors: MAYAK S. , HALEVY A. H. , SAGIE S. , BAR‐YOSEPH A. , BRAVDO B. 
Published: April 2006

AbstractA sharp decline in water potential of petal tissue associated with wilting of cut rose flowers is described. Such a decline did not develop in senescing intact flowers. A circadian rhythm in water absorption by cut flowers was observed.The decline in fresh weight observed in the last phase of the vase life of cut flowers occurred earlier in a short‐lived cultivar than in a longer‐lived one. A decline in potential conductivity to water was observed with time in stems of cut roses. Concomitantly cellulase activity increased after cutting. Flowers held in cellulase solution wilted earlier than the controls. However, no difference was found in these two parameters between two cultivars differing in their longevity. The difference in longevity between the two cultivars was large especially under conditions promoting high transpiration rates, and was narrowed when flowers were either held in mild conditions, or the leaves were stripped off.Although stomates were equally open in intact flowers of the two cultivars, in cut flower shoots of the short‐lived cultivar stomates were more widely open. In accordance transpiration rates were higher, and wilting occurred earlier in the short‐lived cultivar than in the long‐lived one. It is concluded that the earlier wilting of cut flowers of the short‐lived cultivar is mainly due to lower ability to close stomates in response to water stress conditions, and not to earlier formation of vascular blockage.
Further Studies on the Relationship between Growth Regulators and Tuberization of Dahlias
Authors: BIRAN I. , LESHEM B. , GUR I. , HALEVY A. H. 
Published: April 2006

AbstractAbscisic acid (ABA) and gibberellin (GA) treatments, applied to budless leaf cuttings of Dahlia under long day conditions, did not increase the total weight of the cuttings but did affect the region where photosynthates accumulate. GA treatment inhibited the growth of tubers and roots, and enhanced thickening at the petiole base. ABA did not affect the weight of roots or petiole, but promoted the growth of tuberous roots. Anatomical examination of the tuberization revealed that it is caused by inter‐fascicular cambial activity producing parenchyma cells inward. No anatomical difference could be observed between the GA‐induced thickening at the petiole base and the natural or ABA‐induced thickening of the roots. In single node cuttings, taken from various sites along the branch, tuberization ability increased with proximity to the base of the branch, where axillary buds are more inhibited.Short‐day conditions which promote tuberization, increased the endogenous level of ABA‐like inhibitors in intact plants. External conditions and growth substances which inhibit growth also inhibited tuberization. Benzyladenine treatments did not affect tuberization.It is suggested that in addition to their respective indirect effects via the enhancement or suppression of top growth, GA and ABA directly control tuberization. ABA levels which increased under short‐day conditions seem to produce a sink in the roots. GA probably inhibits tuberization by interfering with the trans‐location of photosynthates to the root area.
Role of Ethylene in Induction of Flooding Damage in Sunflower
Authors: KAWASE MAKOTO 
Published: April 2006

AbstractThe possibility that symptoms of flooding damage in plants are primarily caused by an accumulation of ethylene was investigated using pot‐grown sunflower (Helianthus annuus) plants.When plants were flooded to the basal pairs of leaves, ethylene in roots and stems below the water line began to increase. This coincided with the start of hypocotyl hypertrophy and new root formation in hypocotyls, which continued for 14‐16 days. There were highly significant correlations between ethylene concentration and number of roots and hypocotyl diameter.After approximately 4 days of flooding, ethylene concentrations in stems between nodes for the 1st and 3rd basal pairs of leaves started to increase, coinciding with initiation of chlorophyll breakdown and epinasty of the 2nd basal pairs of leaves. Thus, there were correlations between ethylene concentration and chlorophyll breakdown and epinasty. The lower the leaves, the more chlorophyll breakdown among 1st, 2nd, 3rd, and 4th basal pairs of leaves. The longer the flooding, the more severe the flooding damage; and even when returned to normal condition, plants flooded longer than 3 days were not able to recover from flooding damage.A gas chromatographic study revealed that Ethephon was absorbed by roots and decomposed to ethylene in the plant. Damage symptoms caused by soil application of Ethephon, such as reduced stem height, chlorophyll breakdown, epinasty of the 2nd basal pairs of leaves, and hypocotyl hypertrophy, were almost identical with those caused by soil flooding treatment.Microscopic studies revealed that radially enlarged cells and increased intercellular spaces in the cortex were the major contribution to the increased hypocotyl diameter in both flooded and Ethephon‐treated plants.It is concluded that the increase in ethylene concentration in flooded plants is largely, although not exclusively, responsible for flooding damage symptoms.
Regulation of Growth in Avena (Oat) Stem Segments by Gibberellic Acid and Abscisic Acid
Authors: KAUFMAN PETER B. , JONES RICHARD A. 
Published: April 2006

AbstractThe purpose of this study was to analyze the nature of the interaction between gibberellic acid (GA3) and abscisic acid (ABA) in the regulation of growth in excised Avena (oat) stem segments. Growth, compared to sucrose controls, was inhibited by ABA in the range of 10−4 to 10−6M. GA3‐promoted growth was also inhibited by ABA in the same concentration range. A Lineweaver‐Burk analysis of the interaction between GA3 and ABA indicated that ABA acts in a non‐competitive fashion with GA3. This same result was obtained previously with GA3‐indoleacetic acid (IAA) and GA3‐kinetin interactions with Avena stem sections. Our results indicate that ABA can inhibit GA3‐promoted growth within physiological concentrations, and that it is probably acting at a different physiological site from that for GA3.
Effect of Temperature and Kinetin on the Germination and Endogenous Hormones of Hyoscyamus muticus Seeds
Authors: ELKINAWY MAHASEN , HEMBERG TORSTEN 
Published: April 2006

AbstractGermination of Hyoscyamus muticus L. seeds was investigated under different temperature, light and kinetin treatments. Diurnal temperature fluctuation of 25°C for 14 h and 5°C for 10 h, strongly promoted germination. Kinetin (60 mg/1) substituted for the periodic temperature changes. Both kinetin and diurnal temperature fluctuation increased the IAA level in the seeds prior to germination. A natural inhibitor (Rf 0.6–0.8) did not disappear in response to either treatment.
Isoperoxidase Activity and Induction in Cultured Tissues of Wild Carrot: a Comparison of Proembryos and Embryos
Authors: Wochok Zachary S. , Burleson Brent 
Published: April 2006

AbstractSeveral anodic isoperoxidases were found in embryonic tissues of cultured wild carrot, Daucus carota L., which were not present in the proembryo masses from which they originate. This difference is further reflected in the higher specific activity of peroxidase in embryo extracts as compared to proembryonic tissues. The absence of anodic isoperoxidases and depressed peroxidase activity in carrot tissue cultures in the presence of 2,4‐dichlorophenoxyacetic acid (2,4‐D) suggests a regulatory role for this plant growth regulator in controlling peroxidase activity.
Control of the Light Saturation Point for Photosynthesis in Tomato
Authors: MILES C. D. 
Published: April 2006

AbstractThe light saturation curves for photosynthesis in Lycopersicon esculentum have been studied for a yellow‐green mutation and for hormone treated plants. Comparisons have been made between saturation point and the size of the photosynthetic unit in these plants. These data suggest a function in the regulation of photosynthetic rates.
Effects of Varying Light Intensities and Temperature Treatments Applied to Whole Plants, or Locally to Leaves or Flower Buds, on Growth and Pigmentation of ‘Baccara’ Roses
Authors: BIRAN I. , HALEVY A. H. 
Published: April 2006

AbstractVarying light intensity and temperature treatments were applied to whole plants, or to the leaves, or to the flower buds of ‘Baccara’ roses. The effect of these treatments on flower dimensions and pigmentation of the petals was examined.Cooling only the leaves had no effect; cooling only the buds enhanced both bud weight and pigmentation, but the effect was less marked than when the whole plant was cooled. Reducing plant temperature by misting with desalinated water enhanced both pigmentation and flower size.Darkening of only the leaves, or their removal, resulted in an inhibition of the pigmentation and also in a decrease in bud weight. Darkening of only the flower bud did not affect either pigmentation or bud weight, but caused bud elongation. It is suggested that light intensity and temperature affect flower growth and pigmentation via their effects on the availability of sugars in the flower bud.
Effects of Short‐Term Heat and Shade Treatments on Petal Colour of ‘Baccara’ Roses
Authors: BIRAN I. , HALEVY A. H. 
Published: April 2006

AbstractGrowth and pigmentation of ‘Baccara’ rose buds were followed. Petal elongation mainly occurred during a short period of time after the flowering shoot had stopped elongating. Approximately 90% of the flower pigments were synthesized during a short period lasting from the time the bud was 75% to the time it was 100% of its diameter at opening time. Petal growth continued after this period so that the pigments in the petal were “diluted”. Heat stress applied to whole plants or to flower buds only, or a short duration of low light intensities caused “blueing” of the petals when these conditions prevailed during the period of maximum pigmentation. Stress conditions prior to this period or following it, had no effect. We suggest that stress conditions such as high temperature or low light intensities reduce the availability of sugars. When this occurs at the time of maximum pigment production, a fall in the level of pigment occurs, which results in the “blueing” of the petals.
Glutamic Dehydrogenase and Glutamic‐oxaloacetic Transaminase in Apple Tree Tissues
Authors: COOPER D. R. , HILL‐COTTINGHAM D. G. 
Published: April 2006

AbstractA technique is described whereby active preparations of glutamic dehydrogenase (GDH) and glutamic‐oxaloacetic transaminase (GOT) can be obtained from all apple tree tissues using a hand‐operated coffee mill. The amount of insoluble polyvinylpyrrolidone required and the composition of the extractant have been investigated together with the degree of replication obtained and the stability of the resultant extracts.After extraction of all tissues the proportion of both GDH and GOT found in the supernatant was far greater than that in the mitochondria. Addition of calcium and some other metal ions to the assays resulted in some increase in GDH but had no effect on GOT activity. With crude extracts the effect of added calcium was small but after ultrafiltration or acid precipitation it was greatly increased.The co‐factors NADH, NADPH and NAD were all active with GDH in extracts of apple leaves, stem bark and roots. No activity was found with NADP. In the presence of added calcium ions the ratios of activity NADH:NADPH and NADH:NAD were approximately 10:1 and 20:1 respectively.The seasonal variations in specific activity of GDH and GOT in apple leaves, stem bark and wood, and old and young roots were determined separately. The highest GDH activities were found in the leaves in October and in the stem bark in May, while in other tissues activities were generally higher in winter than in summer. The seasonal patterns for GOT activity were very similar to those for GDH except that in the leaves the level changed little through the year.The results are discussed in relation to published work on these enzymes in other plants and to their possible role in the apple tree.
Intensity of Bud Dormancy in Douglas‐fir and Its Relation to Scale Removal and Rooting Ability
Authors: ROBERTS A. N. , TOMASOVIC B. J. , FUCHIGAMI L. H. 
Published: April 2006

AbstractUniform 1‐ or 2‐year‐old rooted cuttings of 3 Douglas‐fir, Pseudotsuga menziesii (Mirb.) Franco, clones were grown under natural conditions in containers from July 1, 1971 to February 15, 1972. At 2‐week intervals, plants from this natural temperature and daylength environment were moved into controlled, long day (LD‐18 h) and short day (SD‐9 h) environments to measure the intensity of bud dormancy from its inception to termination based on number of days to bud break and percentage of expanding buds on a given date. Growth responses to bud scale removal were also helpful in describing the degree and nature of bud dormancy. The cessation of initiatory activity at the bud apex, reflected in the needle number of the subsequent growth flush, corresponded to a September peak of bud dormancy based on the number of days to bud break in the LD environment. Similarly, the cold requirement for breaking bud dormancy was measurable in the SD environment. The use of such rest intensity indices is illustrated in the close relationship established between bud dormancy development and stem cutting rooting ability.
In vitro Plant Formation from Stem Explants of Rape (Brassica napus cv. Zephyr)
Authors: KARTHA K. K. , GAMBORG O. L. , CONSTABEL F. 
Published: April 2006

AbstractInternodal segments from 6‐weeks‐old rape plants (Brassica napus L. cv. Zephyr) were induced to differentiate in vitro producing shoots or shoots and roots on synthetic nutrient medium under controlled conditions. Benzyladenine (BA) alone (5 × 10−6 M) induced multiple shoot formation on all stem explants. Roots were induced on shoots when recultured on nutrient medium supplemented with auxins such as naphthalene‐acetic acid (NAA) or indoleacetic acid (1AA) or when planted in vermiculite. Complete plant formation was obtained when NAA (2 × 1−6, 5 × 10−6 and 10−5 M) was employed in conjunction with BA at 5 × 10−6M. At higher concentrations (10−5M) NAA retards the shoot development while 1AA suppresses it totally. Lower levels of auxins along with the cytokinin did not retard or inhibit shoot differentiation.
Factors Affecting the Sexual Reproduction of a Dermatophyte, Arthroderma benhamiae, in Synthetic Media
Authors: DAVIDSSON MAJVOR , UNESTAM TORGNY 
Published: April 2006

AbstractSexual reproduction of many dermatophytes is easily induced in complex media such as soil plus keratin. In Arthroderma benhamiae this process could be initiated also in synthetic agar media. A number of carbon sources (glucose, fructose, galactose, mannose, maltose, lactose, sorbose, sucrose) had about the same stimulatory effect on reproduction, while xylose was inhibitory. Organic sulphur was not crucial for the process in contrast to the nitrogen supply. The nitrogen sources could be divided into four groups; I. very stimulatory (arginine, citrulline, isoleucine, leucine, ornithine, phenylalanine, proline, valine, glutathione); II. stimulatory (alanine, asparagine, lysine, serine); III. slightly stimulatory (aspartic acid, cysteine, glutamic acid, glycine, histidine, urea, NH4Cl, NH4‐tartrate); IV. inhibitory (hydroxyproline, methionine, threonine, tryptophan). Synergistic effects were shown between some amino acids. Generally a combination between 5 g/l glucose and 300–400 mg/l nitrogen induced the largest number of cleistothecia, regardless of the nitrogen source used. The level varied between the sources, however. A C/N ratio of about 10 was optimal while a value above 20 gave no cleistothecia. The optimal temperature for the process was 30°C. Sexual reproduction occurred between pH 4.4 and 8.0 (final values). However, at a final pH above 7.2 the number of ascospores/cleistothecium was reduced.
Extracellular Lytic Enzymes of Myxococcus virescens
Authors: HASKÅ GUNO 
Published: April 2006

AbstractAn easy and rapid method for the purification of a bacteriolytic endopeptidase produced by Myxococcus virescens is described. The bacteria were grown in casitone media and the cells were sedimented by centrifugation. About 1.2 g of montmorillonite were added per liter of cell‐free culture solution. The clay was sedimented by centrifugation and the enzyme was then eluted by 0.05 M Na‐phosphate buffer pH 6.0, containing 0.4 M NaCl. The enzyme was diluted with water and chromatographed on carboxymethyl‐cellulose columns.The purified enzyme liberated free amino groups but no reducing sugars or N‐acetylhexosamines when acting on purified N‐acetylated cell walls of Micrococcus lysodeikticus. Analysis of N‐ and C‐terminal amino acids in the digestion products showed that the enzyme had liberated about 110 nmoles of lysine ε‐amino groups and 60 nmoles of alanine carboxyl groups per mg of cell wall. When it acted on a bisdisaccharide pentapeptide dimer isolated from M. lysodeikticus cell walls, it cleaved about 30% of the alanyl‐lysine linkages. Consequently the enzyme was an alanyl‐lysine endopeptidase. It had no muramyl‐alanine amidase activity.
Effects of Moderate Water Deficit (Stress) on Wheat Seedling Growth and Plastid Pigment Development
Authors: DUYSEN MURRAY E. , FREEMAN THOMAS P. 
Published: April 2006

AbstractEtiolated 6‐day‐old wheat (Triticum aestivum L. cv. Chris) seedlings were subjected to osmotic stress by an application of polyethylene glycol 12 h prior to the exposure to a continuous 72‐h light period. The water potential of the primary leaf of stressed seedlings was between –9 and –14 bars throughout the light period.Stress impaired seedling growth, leaf unfolding, and the increase in leaf area. The imposed osmotic stress reduced total chlorophyll accumulation, particularly after 9 h light, suggesting that this is the approximate time period for the depletion of the protochlorophyll(ide) pool and the pool of an essential protochlorophyll(ide) precursor. The chlorophyll a/b ratio of extracts from stressed and non‐stressed plants was the same during the 72‐h greening period. Water deficit stress impaired carotenoid accumulation sooner than the impairment of chlorophyll production suggesting either a smaller carotenoid pool size of precursors or that the metabolic pathway of carotenoid synthesis was more sensitive to stress. Shifts from the usual plastid pigment absorbance maxima were not observed in these studies.
Occurrence of Endogenous Indol‐3yI‐Aspartic Acid in Light and Dark‐Grown Bean Seedlings (Phaseolus vulgaris)
Authors: TILLBERG ELISABETH 
Published: April 2006

AbstractAn acid ether‐soluble, strongly growth‐stimulating substance revealed by the Avena coleoptile straight‐growth test in methanol extracts from bean seedlings (Phaseolus vulgaris L.) was identified as indol‐3yl‐aspartic acid (IAAsp). Points of agreement between synthetic IAAsp and the investigated growth stimulator were indicated by chromatographic behavior, elution volume in gel filtration, mobility in paper electrophoresis, “colour reaction” with DMCA reagent, ability to form indol‐3yl‐acetic acid (IAA) and aspartic acid after hydrolysis and, finally, biological activity in the Avena test. Furthermore, some experiments demonstrated the occurrence of an inhibitor in extracts from light‐grown tissue. This masked the stimulation of IAAsp in the Avena test when the extracts had been chromatographed in isopropanol: NH3:H2 O. A comparison of the levels of IAAsp between green and etiolated tissue did not reveal any distinct difference, demonstrating that the IAA conjugate IAAsp does not participate in the regulation of the photomorphogenesis.
Regulation of Leaflet Photosynthesis by Developing Fruit in the Pea
Authors: FLINN A. M. 
Published: April 2006

AbstractChanges in the net photosynthesis of leaflets of Pisum sativum L. (cv. Onward) were found to reflect closely the pattern of assimilate demand in subtended fruit during development. An early peak in leaflet photosynthesis corresponded with the rapid elongation of the fruit; a second peak with the inflation of the pod and initiation of seed growth. However, where the subtended fruit was removed at anthesis, the pattern of fluctuation in leaflet photosynthesis was altered, while leaflets at vegetative nodes maintained a lower photosynthetic rate which fluctuated little. The pattern of net photosynthesis in the fruit appears to reflect the high respiration rates associated with pod elongation and seed growth. This closely coupled system, where fruit assimilate demand modulates the photosynthesis of adjacent leaflets, provides a scope for study of source‐sink relationships with the minimum of experimental manipulation.
Studies on the Nitrogen Metabolism in Ectomycorrhizae
Authors: KRUPA SAGAR , BRÄNSTRÖM GUNNAR 
Published: April 2006

AbstractConcentrations of free and bound amino acids were determined in 1) the mycorrhizal fungus Boletus variegatus Fr. 2) nonmycorrhizal root systems of aseptically grown Pinus sylvestris L. seedlings, and 3) mycorrhizal root systems of seedlings developed aseptically using the two symbionts.Arginine (total) was the major amino acid constituent in the mycelium of B. variegatus (18%–22%) during the exponential phase of growth. While 59%–86% of the available arginine was bound during the acceleration phase of growth, in the logarithmic phase 63%–75% was in the free pool. There were differences in the proportions between the individual amino acids in the bound fraction at different stages of growth suggesting production of diverse proteins.Twenty per cent of the amino acid content of uninfected P. sylvestris root systems was arginine. Infection of the root systems by the fungal symbiont did not result in an increase but a slight decrease in the free arginine content of the composite structure. Almost all other amino acids in the free pool were found in higher concentrations in the mycorrhizal root system. It is suggested that arginine synthesis in B. variegatus is repressed by the arginine available in the host. The mycorrhizal fungus possibly metabolizes the host arginine pool ultimately resulting in more efficient protein synthesis in both the partners.
Effect of Potassium on Proline Accumulation in Maize during Wilting
Authors: MUKHERJEE ILABANTA 
Published: April 2006

AbstractLeaf discs from maize (Zea mays) grown at high as well as low level of potassium, were treated with different concentrations of KC1 for 2 h in light before exposing to wilting conditions. An enhanced accumulation of free proline effected by wilting was observed in potassium treated discs. Although proline accumulation was much less in leaf discs exposed to short‐term severe wilting conditions than in those exposed to long‐term mild wilting conditions, the effect of potassium was still evident. Under long‐term mild wilting conditions, the enhanced effect was greater in leaf discs from plants grown at high level of potassium than in those from plants grown at low levels of potassium. Treatment with NaCl instead of KC1 did not lead to extra accumulation of proline.
Rhamnose Bound Indole‐3‐Acetic Acid in the Floral Parts of Peltophorum ferrugineum
Authors: GANGULY T. , GANGULY S. N. , SIRCAR P. K. , SIRCAR S. M. 
Published: April 2006

AbstractThe presence of rhamnose bound indole‐3‐acetic acid (IAA) was reported from acetone extract of anthers and carpels of the flowers of Peltophorum ferrugineum. Hydrolysis of the sugar ester gave IAA and rhamnose. Identification of IAA was based on physical measurements supported by bioassay. Bound and free IAA were not detected in petals, seeds and seed coats.