bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nutrient Requirements of Vigna sinensis Callus Cultures
Authors: REDDY K. B. S. MURTHY , NARAYANA R. 
Published: April 2006

AbstractNutrient requirements of callus tissues previously obtained from Vigna sinensis hypocotyl segments were investigated on modified White's (Miller and Skoog) and Murashige and Skoog's media containing 1 mg/1 of each of 2,4‐D and kinetin, 2% sucrose and 1% agar. Yields of tissues on the latter medium were 3 times more than the former. After studying various organic and inorganic nutrients, two synthetic media have been developed for callus cultures. The above modified White's medium further supplemented with 2% sucrose, and 500 mg/1 of urea or asparagine was suitable for a compact callus with a dry‐to‐fresh‐weight ratio around 8% and on this the tissues grew 15‐ to 17‐fold in 5 weeks. Similarly the Murashige and Skoog's medium further enriched with 2% sucrose, 400 mg/1 of urea or a mixture of aspartic acid (750 mg/1), glutamic acid (250 mg/1), asparagine (250 mg/1) and arginine (250 mg/1), was apt for a friable callus with a dry to fresh weight ratio of 3 to 4% and it promoted a 45‐ to 50‐fold increase in growth in 5 weeks.
Supraoptimal Temperature Effects upon Agrostis palustris
Authors: DUFF D. THOMAS , BEARD JAMES B. 
Published: April 2006

Abstract Agrostis palustris sods were grown sequentially in a controlled environment chamber at 20–10, 25–15, 30–20, 35–25, and 40–30°C day‐night temperature regimes. Leaves grown at 40–30°C contained 53% more ethanol soluble and 51% more water soluble carbohydrate than those grown at the 4 lower temperature regimes. The increase in ethanol and water soluble carbohydrate in leaves at 40–30°C could not be attributed to a blockage in translocation of photoassimilate to lower plants parts based on quantitative carbohydrate analyses on stem and stolon tissue.Manometric measurements of photosynthesis indicated that leaf blades grown at the five temperature regimes exhibited different rate capabilities when tested under non‐limiting light and carbon dioxide levels. Oxygen evolution increased directly with temperature from 20 to 40°C and was 8 to 11 fold greater than the rate of carbon dioxide evolution. Both quantitative and qualitative differences in the photosynthetic rate were postulated in the leaf blade tissue tested. The quantitative difference was attributed to a possible difference in the number of cells per unit area and their size. The qualitative difference was attributed to greater thermal stability of leaf proteins when plants were grown at supraoptimal temperatures.Manometric respiratory rate studies did not indicate similar differences in temperature response in leaf blade tissue grown at the five temperature regimes. The cause of decreased shoot growth at supraoptimal temperatures could not be attributed to decreased and limiting C‐6 carbohydrate synthesis.
Growth and Morphogenesis in Tissue Cultures of Anagallis arvensis
Authors: BAJAJ Y. P. S. , MÄDER M. 
Published: April 2006

AbstractMorphogenesis has been induced in excised organs and callus tissue cultures obtained from various parts of the seedling and mature plants of pimpernel (Anagallis arvensis). Vigorously growing cell cultures capable of being periodically subcultured have been established in liquid as well as on the agar‐solidified Murashige and Skoog's medium supplemented with 2,4‐D (0.1 mg/1) + kinetin (0.1 mg/l) + coconut milk (10%). The callus tissue obtained from excised hypocotyl segments is white, soft, friable and fast growing, and has been subcultured over a period of two years without showing any sign of decline in growth. The optimum conditions for growth are at pH 5.9, temperature 27°C, and with 4% sucrose as the carbon source. Under appropriate nutritional supply these cultures can be manipulated to induce rhizogenesis in the suspension cultures, and buds and “embryo‐like” structures on agar‐solidified media.The excised leaves, hypocotyl and stem segments regenerate buds. Of the cytokinins used, 6‐(y,y‐dimethylallylamino)‐purine proved to be the best for the number of cultures producing buds, as well as for the number of buds per culture. Anatomical studies revealed that buds arise from the epidermal and subepidermal layers of leaves and hypocotyl; these buds form shoots which eventually develop into plantlets.
The Influence of NAA, BA and Temperature on Shoot and Root Development from Begonia×cheimantha Petiole Segments Grown in vitro
Authors: FONNESBECH MOGENS 
Published: April 2006

AbstractThe effect of exogenously supplied NAA and BA on the shoot and root formation in isolated petiole segments of Begonia×cheimantha was determined in vitro on a modified White medium at a constant temperature of 24°C. The best development of normally appearing plants was obtained on media containing 0.01 mg × 1−1 of NAA and 0.5 to 1.0 mg × 1−1 of BA. Lower concentrations of BA yielded no shoots, higher concentrations promoted shoot formation, but the shoots were abnormal with malformed leaves. Lower concentrations of NAA resulted in poorer survival rate and no roots, with higher concentrations of NAA many roots developed, but these were thickened and their longitudinal growth inhibited. Temperature proved to be of utmost importance for the induction of shoot formation. Thus significantly fewer shoots were formed at the higher temperature (25°C) than at lower temperatures (15 to 20°C). Temperature immediately after initial transfer was of greatest importance: 25°C, during the first week followed by low temperature, produced very few shoots.
Interrelationship of Abscisic Acid and Gibberellic Acid in the Promotion of Callus Formation in the Abscission Zone of Citrus Bud Cultures
Authors: ALTMAN ARIE , GOREN RAPHAEL 
Published: April 2006

AbstractThe mechanism of ABA‐induced callus formation was studied in sterile bud cultures of Citrus [Citrus sinensis (L.) Osbeck] on defined media. ABA was found to promote callus formation in the abscission zone between the petiole and the branch while inhibiting bud growth. The promoting effect of ABA was dependent on the physiological state of the shoot from which buds were excised, and on the size of the explant. Callus formation was highest in autumn and summer (i.e. younger) buds, and lowest in older buds excised from previous summer flush.GA was only slightly active in promoting callus formation when applied separately, but showed a highly synergistic effect when applied with ABA: maximal callus formation was attained at a combination of 10−5M ABA and 10−6 MGA in the medium. Subcultures of ABA‐induced callus revealed that ABA inhibited the growth of isolated subcultured callus, while IAA and kinetin, and especially GA, promoted its rapid proliferation. A general decrease in protein synthesis was found in the abscission zone during the first 5 days of induction, while total protein content changed only slightly.The results suggest that ABA‐induced callus formation in Citrus bud explants is a multiphasic phenomenon involving, at least, two stages: (1) activation of certain cells in the abscission zone by ABA, resulting in the formation of callus layers, and (2) subsequent proliferation of the callus tissue, which is dependent on the hormonal balance in the explant. This growth‐promoting effect of ABA seems to be a general phenomenon in explants exposing a cut‐surface.
Regulators of Cell Division in Plant Tissues
Authors: LETHAM D. S. 
Published: April 2006

AbstractProcedures were devised for purification of the cytokinins in the milk of mature coconuts (Cocos nucifera fruits). One cytokinin isolated in crystalline form was unequivocally identified as 9‐β‐D‐ribofuranosylzeatin. This compound appeared to account for a large proportion of the cytokinin activity in n‐butanol extracts of coconut milk. The activity which was not extracted by n‐butanol was largely due to unidentified compounds which could be partially purified by adsorption onto and elution from charcoal.
Translocation and Complex Formation of Picloram and 2,4‐D in Rape and Sunflower
Authors: HALLMÉN ULF 
Published: April 2006

AbstractUptake, translocation and complex formation of 14C‐labelled 4‐amino‐3,5,6‐trichloropicolinic acid (picloram) and 2,4‐dichlorophenoxyacetic acid (2,4‐D) in seedlings of rape (Brassica napus L. cv. Nilla) and sunflower (Helianthus annuus L. var. uniflorus) were studied. Sunflower is susceptible both to 2,4‐D and picloram, while rape is susceptible to 2,4‐D but more tolerant to picloram. The uptake of the herbicides through the leaves was almost complete in both species. Translocation of 2,4‐D into the roots took place more readily than that of picloram. In sunflower about 50 per cent of the applied 2,4‐D was extruded through the roots into the nutrient solution after 9 days. In the picloram‐treated sunflower most of the activity was found in the aerial parts, while in picloram‐treated rape most of the activity still occurred in the treated leaf after 9 days. No activity at all was found in the roots or in the nutrient solution of the picloram‐treated rape seedlings.While the major part of 2,4‐D always was found in the state of free herbicide, a large fraction of picloram was rapidly bound into water‐soluble complexes. This binding was especially pronounced in rape. Separation by paper chromatography showed that different radioactive compounds were formed. Most of these could be hydrolyzed, thereby releasing free herbicide.The results support the hypotheses that complex formation could counteract herbicide translocation and toxicity of auxin herbicides.
Root Formation in Pea Cuttings
Authors: MOHAMMED SHAFAAT , ERIKSEN E. NYMANN 
Published: April 2006

AbstractAuxin was applied to the upper part of the cuttings, which were both decapitated and disbudded on the same day. The applied auxin was removed by redecapitating the cuttings at different time intervals. In a second experiment, auxin was applied either to the upper or lower part of the decapitated and disbudded cuttings at different time intervals.In cuttings, which were redecapitated after 1 and 2 days, the root formation was reduced considerably. The redecapitation after 3 days had no adverse effect on the root formation. Cuttings treated with auxin at different time intervals showed a weaker root promotion on days 0 and 1 than on the subsequent days.The results emphasize the fact that auxin is active only during the first part of the root initiation phase. A continuous flow of auxin for a period of the first 3 days during the root initiation is of overriding importance. There appears to be at least two different stages of the root initiation phase, (ia) auxin active stage, and (ib) auxin inactive stage. The results also seem to indicate that some other factors, in addition to auxin, are active during the first stage of the root initiation phase.
Kinetic Studies of a (Na++ K++ Mg2+) ATPase in Sugar Beet Roots
Authors: LINDBERG SYLVIA , HANSSON GUNNAR , KYLIN ANDERS 
Published: April 2006

AbstractKinetic studies of a microsomal, dithiotreitol treated, homogenate from sugar beet roots led to the following conclusions about its ATPase activity: (1) MgATP in complex appears to be the primary substrate for the reaction. The reciprocal equilibrium constant for the binding to the enzyme is estimated to be approximately 0.2 × 10−3M. (2) Free ATP acts as a competitive inhibitor of the MgATP. The binding constant is about twice as high as for MgATP. Consequently the enzyme has less affinity for ATP than for MgATP. (3) Free Mg2+ has little influence on the velocity, as the binding affinity of the enzyme for Mg2+ is almost negligible.
DNA Synthesis, Mitosis and Ploidy of Dividing Cells in Early Crown Gall
Authors: KUPILA‐AHVENNIEMI SIRKKA , THERMAN EEVA 
Published: April 2006

AbstractDNA synthesis, mitosis and ploidy of dividing cells were studied during 30 h after wounding around wounds inoculated with Agrobacterium tumefaciens, around sterile wounds and in control stems of Vicia faba. DNA synthesis was examined by counting nuclei labelled with 3H‐thymidine in slides in which mitoses had been counted and analyzed before autoradiography.The main results were that around inoculated wounds, DNA synthesis and the number of mitoses showed a peak between 12 and 22.5 h. Both types of wounding induced mitoses, many of them polyploid (DNA content higher than 4C), both in the pith and the cortex, whereas in the control stems only diploid mitoses, mostly in the stelar area, were seen. The first polyploid (8C) mitoses around the inoculated wounds took place at 12 h and at 15.5 h 32C mitoses were seen; around the sterile wounds the first 8C divisions occurred at 26 h. The frequency of polyploid mitoses and their degree of ploidy continued to be considerably higher around the crown gall than around the control wounds. When a cell with a higher than 4C content is induced to divide, the 12 chromosomes, as a rule, consist of four, eight, 16 or 32 chromatids, instead of the normal two.The early division of highly polyploid cells around the inoculated wounds is obviously caused by growth factors which are known to be produced by the bacteria. It appears possible that this ability to synthesize excessive amounts of growth factors is subsequently transferred to the host cells through bacterial DNA.
On the Metabolism of Tortula ruralis Following Desiccation and Freezing: Respiration and Carbohydrate Oxidation
Authors: BEWLEY J. DEREK , THORPE TREVOR A. 
Published: April 2006

AbstractRecovery from desiccation by Tortula ruralis (Hedw.) Gaertn., Meyer and Scherb was accompanied by an immediate, rapid increase in respiration (measured as oxygen uptake) at 25.5°C or 3.5°C. The respiratory burst was greater on rehydration of moss which had been rapidly desiccated over silica gel than that which had been more slowly desiccated in atmospheres of high relative humidity. No respiration was observed in dry moss. Dried moss which had been placed in liquid nitrogen resumed respiration on rewarming and rehydration but moss which had been frozen in the hydrated state respired to a lesser extent and showed signs of freeze damage. In the initial stages of slow drying a slight increase in respiration was noted, followed by a gradual decrease as drought became more severe.In contrast to observations made on many higher plants under drought stress, this moss did not exhibit any changes in its starch and sugar content during or following desiccation, nor were there any changes in free proline levels. Using (1‐14C)‐glucose and (6‐14C)‐glucose, the relative activities of the Embden–Meyerhof–Parnas and pentose phosphate pathways in hydrated and rehydrated moss were determined, as were the activities of specific enzymes involved in these pathways. An increased activity of the Embden–Meyerhof–Parnas pathway of glucose oxidation on rehydration of Tortula was observed. The possible significance of this latter observation is outlined.
Hormone‐Induced Reversal of Color Change and Related Respiratory Effects in Ripening Apricot Fruits
Authors: ABDEL‐GAWAD HESHAM , ROMANI ROGER J. 
Published: April 2006

AbstractPreharvest applications of N6‐benzyladenine and gibberellic acid caused a lowering of respiratory rates and a transient reversal in the color changes normally associated with the postharvest ripening of apricot fruits (Prunus armeniaca L.) Light transmission at 589 and 657 nm were used to detect color change. A physiological and metabolic link is implied by the close temporal coincidence of both the reversal in color change and the reversal in respiratory rate that occurs at the climacteric minimum. Postharvest treatments with the same phytohormones had generally similar but much less pronounced effects.
Root Formation of Pea Cuttings in Relation to the Irradiance of the Stock Plants
Authors: HANSEN JÜRGEN , ERIKSEN ERIK NYMANN 
Published: April 2006

AbstractPea plants were grown at different irradiances for eleven days. At this stage they were used for cuttings. The irradiance during the rooting period (155 mW · dm−2) was the same in all the experiments, Cuttings from stock plants cultivated at the weakest irradiance obtained the highest number of roots, and the poorest rooting appeared in cuttings from stock plants grown at the highest irradiance. The results indicate that the nutritional status of the stock plant is an important factor for root formation in the cutting. Light may influence the production of inhibitors which directly or indirectly affect root formation. The possible role of carbohydrates and growth promoters in the process of root formation is discussed.
Proline‐Dehydrogenase from Pumpkin (Cucurbita moschata) Cotyledons
Authors: RENA ALEMAR B. , SPLITTSTOESSER WALTER E. 
Published: April 2006

AbstractA NAD specific proline‐dehydrogenase was found in pumpkin (Cucurbita moschata Poir. cv. Dickinson Field) which oxidized proline to Δ1‐pyrroline‐5‐carboxylate. NADP did not substitute for NAD and L‐proline‐methyl‐ester and thiazolidine‐4‐carboxylate were substrates in the reaction, at a rate of 107% and 33% respectively, of the rate with L‐proline. Pumpkin cotyledons contained the bulk of the enzyme activity with 90% of the activity being in the soluble fraction. Proline‐dehydrogenase, which was not treated at high temperature, was stable at –10°C for 4 months in the presence of high ammonium sulfate concentration. The Michaelis constant for NAD was 2.2 mM and for L‐proline was 2.5 mM. At 5 mM NADP, a 40% non‐competitive inhibition of proline‐dehydrogenase was obtained, while 50 μM NADP was sufficient to induce 20% inhibition.
Effect of Age on Adenosine Triphosphatase Activity from Tobacco Chloroplasts
Authors: SCHERINGS G. , KUIPER P. J. C. 
Published: April 2006

AbstractAdenosine triphosphatase activity of tobacco leaf chloroplasts in the dark was measured, using leaves of different age as determined by the position of the leaves along the stem. The activity of the chloroplast preparations strongly decreased with age, regardless of the addition of Mg2+ or Ca2+. Opposite effects of Mg2+ and Ca2+ on the activity of the chloroplasts were noted in experiments where different ratios of Mg2+/Ca2+ were applied. They were related to the age of the leaves, Ca2+ strongly stimulated the activity of the preparations from old leaves but was practically without effect in young, just expanded leaves. Mg2+ slightly stimulated the activity from old leaves while it invariably inhibited the hydrolytic activity of preparations from young leaves.
Effect of (2‐Chloroethyl)phosphonic Acid on Flower Induction in Juvenile Mango (Mangifera indica) Seedlings
Authors: CHACKO E. K. , KOHLI R. R. , SWAMY R. DORE , RANDHAWA G. S. 
Published: April 2006

AbstractSpray applications of 1000 mg/l (2‐chloroethyl)phosphonic acid (CEPA) five times, at weekly intervals, during November and early December induced heavy flowering in ringed and nonringed juvenile mango seedlings. The treated plants produced flower buds which opened by the end of December, while the control and ringed seedlings produced only a new flush of vegetative growth. The results show that CEPA could be profitably used for early evaluation of hybrid seedlings in mango breeding programme.
Partitioning of Cytokinins between Ethyl Acetate and Acid Water Phases
Authors: HEMBERG TORSTEN 
Published: April 2006

AbstractModel‐experiments to determine the quantitative yield in purification of cytokinin extracts have been performed with kinetin, isopentenyladenine and zeatin and with their ribosides. When these substances in water solution of pH 3 are shaken three times with equal volumes of ethyl acetate, most of the kinetin and isopentenyladenine and their ribosides go over to the ethyl acetate phases. Zeatin and its riboside stay in the water phase. The unsuitability of using ethyl acetate to purify cytokinin extracts is pointed out.
Control of Aromatic Amino Acid Biosynthesis in Cultured Plant Tissues: Effect of Intermediates and Aromatic Amino Acids on Free Levels
Authors: WIDHOLM J. M. 
Published: April 2006

AbstractShikimate, anthranilate, indole, l‐tryptophan, phenylpyruvate, l‐p henylalanine, p‐hydroxyphenylpyruvate or l‐tyrosine were added to suspension‐cultured Nicotiana tabacum (tabacco) and Daucus carota (carrot) tissues and incubated for 24 hours. Uptake of each compound was substantial as measured by its decrease in the medium.The levels of free tryptophan, phenylalanine and tyrosine were determined in the tissues after the 24 hours incubation. Shikimate did not change the aromatic animo acid levels in carrot tissue, but did increase all three in tobacco (3‐fold or more), indicating a less stringent feedback control in tobacco.Anthranilate and indole increased the tissue tryptophan levels in both species by at least 17‐fold, showing that the flow from anthranilate and indole to tryptophan was apparently unhindered by enzymatic control mechanisms.When tryptophan levels were elevated in both carrot and tobaccotissues by anthranilate, indole or tryptophan addition, there was also an increase in free phyenylalanine and tyrosine. This might be due to the reversal of phenylalanine and tyrosine feedback inhibition of chorismate mutase by the high tryptophan in the tissue. Chorismate mutase activity in tobacco crude extracts could be inhibited by 66–90% by 1 mM phenylalanine and /or tyrosine. Tryptophan at 1 mM stimulated the enzyme activity by 1/3 and completely reversed the phenylalanine and/or tyrosine inhibition of enzyme activity. Chorsimate mutase activity amino acids under a variety of conditions.Phenylpyruvate increased the phenylalanine levels and p‐hydroxyphenylpyruvate increased the tyrosine levels in carrot and tobacco tissues indicating that there was no feedback control of the last step in phenylalanine and tyrosine biosynthesis.
Effects of Four Temperature Regimens on the Gibberellin Content of Winter Wheat cv. Kharkov
Authors: REID D. M. , PHARIS R. P. , ROBERTS D. W. A. 
Published: April 2006

AbstractKharkov 22 M.C. winter wheat was grown continuously from seed under four temperature regimens; 2°C; 2°C then transferred to 20°C; 6°C, and 20°C. Plants were harvested at the 4‐leaf stage (except the 2°C plants which were harvested at the 3‐leaf stage) and the levels of endogenous gibberellins (GAs) were measured and their cold hardiness determined. The GA content of 20°C and the 6°C seedlings were about equal and greater (by 4‐ to 30‐fold) than the GA content of 2°C seedlings that had been transferred to 20°C (i.e. vernalized). The GA content of the 2°C seedlings was least of all, being 28‐ to 320‐fold less than the 20°C seedlings. At harvest the leaves of the 20°C seedlings were somewhat larger than those of the seedlings grown at 2°C and transferred to 20°C. The leaves of the 6°C seedlings were very much smaller and the leaves of the 2°C seedlings were smallest of all.It is concluded that while GAs may play a role in controlling leaf size and level of cold hardiness of wheat, they are not the most important factor.