Showing papers in "Plant Science Letters in 1982"
TL;DR: Small plants from the pea cross-inoculation group were selected for rapid nodulation on agar in test tubes and strains from the genus Vicia were best, making the culture tube system ideal for genetic studies of Rh.
Abstract: Small plants from the pea cross-inoculation group were selected for rapid nodulation on agar in test tubes. Plants from the genus Vicia were best; strains of the species hirsuta , tetrasperma , sativa and lathyroides nodulated respectively 4, 5, 4 and 7 days after inoculation with Rhizobium leguminosarum RBL 1. Rapid nodulation, visibility of the root system and in situ acetylene reduction makes the culture tube system ideal for genetic studies of Rh. leguminosarum . A number of bacteria including Agrobacterium tumefaciens containing a Sym-plasmid from Rh. leguminosarum formed root nodules. A Vicia sativa strain formed thick and short roots (Tsr) when inoculated with a bacterium harbouring a Sym-plasmid from Rh. leguminosarum . Crown gall formation could also be investigated by wounding of axenic Vicia hirsuta in test tubes.
119 citations
TL;DR: The suitability of root protoplasts for genetic manipulations in the genus Brassica is discussed and plant regeneration was obtained from protoplast derived tissues of B. napus and B. oleracea, but only rhizogenesis was observed with B. campestris.
Abstract: Protoplasts isolated enzymatically from roots of Brassica alba (White Mustard), B. campestris (Turnip), B. napus (Rape) and B. oleracea (Cabbage), divided to form callus. Plant regeneration was obtained from protoplast derived tissues of B. napus and B. oleracea , but only rhizogenesis was observed with B. campestris . Tissues of B. alba remained undifferentiated. The suitability of root protoplasts for genetic manipulations in the genus Brassica is discussed.
116 citations
TL;DR: The embryogenic nature of the callus was maintained for more than a year through 18–20 subcultures and Regenerated plants were shown to have the normal tetraploid chromosome number of 2 n = 4 x = 28.
Abstract: A white and compact embryogenic tissue was obtained from young inflorescence segments of Pennisetum purpureum (Napier or Elephant Grass) cultured on Murashige and Skoog's (MS) and N6 medium containing various concentrations and combinations of 2,4-dichlorophenoxyacetic acid (2,4-D), naphthaleneacetic acid (NAA) and 6-benzylaminopurine (BAP). Somatic embryogenesis was observed in more than 70% of the cultures on media containing 2,4-D. The embryogenic nature of the callus was maintained for more than a year through 18–20 subcultures. Regenerated plants were shown to have the normal tetraploid chromosome number of 2 n = 4 x = 28.
104 citations
TL;DR: Isolated buds of the normally difficult-to-root cultivars Jonathan and Delicious were cultured with 6-benzyladenine (BA) to produce a proliferating shoot culture and there was a progressive improvement in the rooting of microcuttings with increasing numbers of subcultures.
Abstract: Isolated buds of the normally difficult-to-root cultivars Jonathan and Delicious were cultured with 6-benzyladenine (BA) (10 μM) to produce a proliferating shoot culture The shoots were either (i) made into micro-cuttings (50 mm), treated either with α-naphthalene acetic acid (NAA) (10 μM) applied to the medium or with γ-(indole-3)-butyric acid (IBA) (750 μM) applied to the base of the stem and were then tested for formation of adventitious roots in vitro or (ii) were subcultured with BA as before to produce successive generations of shoots The duration of each subculture was 5 weeks When shoot cultures were grown at 26±2°C with continuous illumination (90–100 μE m−2 s−1) there was a progressive improvement in the rooting of microcuttings with increasing numbers of subcultures Freshly cultured materials did not form roots After 9 subcultures 95% of Jonathan microcuttings formed roots With Delicious the percentage rooting was 21 after 4 subcultures and 79 after 31 subcultures
100 citations
TL;DR: Heritable quantitative and qualitative changes can be observed in the nuclear DNA of doubled-haploid (D.H.) plants obtained by pollen culture of Nicotiana sylvestris.
Abstract: Summary Heritable quantitative and qualitative changes can be observed in the nuclear DNA of doubled-haploid (D.H.) plants obtained by pollen culture of Nicotiana sylvestris . D.H. plants resulting from consecutive androgenic cycles contain on the average increasing amounts of total DNA and increasing proportions of highly repeated sequences. All the results suggest that both A-T rich and G-C rich regions are amplified in the D.H. genome. Some hypotheses on the origin of the changes are discussed.
97 citations
TL;DR: Variability in callus growth rate within B. oleracea was as great as that between the species of Brassica and intra-varietal variability asgreat as the variability between species.
Abstract: Callus growth and plant regeneration from callus were studied for 6 species of Brassica differing in chromosome number and ploidy level and for 17 cultivars of B. oleracea having constant chromosome number and ploidy level. Callus was initiated from young hypocotyl explants and was maintained on media supplemented with various concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D), naphthaleneacetic acid (NAA), kinetin and coconut milk (CM). The rate of callus growth and the appearance of this tissue depended upon both the genotype examined and the growth medium. Variability in callus growth rate within B. oleracea was as great as that between the species of Brassica. Callus growth was less vigorous on a medium containing CM and high levels of 2,4-D than on a medium lacking CM and with a low concentration of 2,4-D; however, 2,4-D was shown to be necessary for callus formation. Organogenetic response of calluses tested on two regeneration media demonstrated intra-varietal variability as great as the variability between species. Rate of root and shoot organogesis was enhanced by a 1-week exposure to callus medium lacking 2,4-D.
96 citations
TL;DR: Growth and podophyllotoxin production of callus tissues were examined under various culture conditions as discussed by the authors, showing that IAA and/or NAA in the presence of kinetin and casamino acids promoted callus growth.
Abstract: Growth and podophyllotoxin production of callus tissues were examined under various culture conditions. IAA and/or NAA in the presence of kinetin and casamino acids promoted callus growth, while 2,4-dichlorophenoxyacetic acid (2,4-D) yielded maximum podophyllotoxin. With respect to kinetin, the optimum concentration for callus growth and podophyllotoxin formation was 0.2 ppm, with higher concentrations inhibiting podophyllotoxin biosynthesis. The accumulation of podophyllotoxin was primarily restricted to the rapid growth phase of callus tissues and was strongly affected by the light quality and intensity. The results also indicated that the contents of podophyllotoxin and other lignanes were dependent on the conditions used for callus initiation as well as on the plant part frrm which they were derived.
94 citations
TL;DR: The results indicate that there are no inherent limitations in the C4 mechanism or in the efficiency of energy utilization for carbon assimilation which prevents C4 plants from adapting to low light conditions.
Abstract: Microstegium vimineum, a C4 plant of the family Poaceae, is shown to be extremely adaptable to growing under shade conditions. The capacity for dry matter production of the species was similar from 18% to 100% full sunlight. Even at 5% full sunlight substantial growth occurred (17% of that at full sunlight). In comparison, growth of the C4 species Digitaria sanguinalis and Sporobolus airoides declined rapidly below full sunlight with no growth occurring at 5% full sunlight. A number of measurements on leaves of M. vimineum grown under 5% of full sunlight versus full sunlight reflects the ability of this species to adapt to low light. Under low light there was a 2-fold increase in leaf area per leaf with an approx. 2-fold decrease in leaf thickness. The soluble protein/ chlorophyll ratio increased about 3.5-fold in the low light-grown plants due to an increase in chlorophyll/leaf area and a decrease in soluble protein/leaf area. Under both light regimes the plants had Kranz anatomy and high levels of phosphoenolpyruvate (PEP) carboxylase which are known features of C4 plants. The results indicate that there are no inherent limitations in the C4 mechanism or in the efficiency of energy utilization for carbon assimilation which prevents C4 plants from adapting to low light conditions.
93 citations
TL;DR: In this article, the authors demonstrated a protective effect of glycine betaine against heat destabilization of membranes by using red beet root disks as a model and showed that the magnitude and duration of the response are concentration-dependent and in addition, they are quite similar to those obtained with calcium chloride.
Abstract: A protective effect of glycine betaine against heat destabilization of membranes is demonstrated by using red beet (Beta vulgaris) root disks as a model. The magnitude and the duration of the response are concentration-dependent and in addition, they are quite similar to those obtained with calcium chloride. Significant stabilizing effects are obtained with an external concentration of glycine betaine of 50 mM. At lower concentrations betaine can exert a synergistic effect with CaCl2 and also with NaCl and KCl. The physiological relevance of these results, in respect to salt and stress tolerances, is discussed.
79 citations
TL;DR: Temperature-dependence of the spermine and calcium effect on ethylene biosynthesis was correlated with specific changes induced by them in the microviscosity of microsomal membranes of apple tissue.
Abstract: Inhibition of ethylene biosynthesis in apple fruit discs by calcium and spermine differed in character in at least three respects: (i) as the fruit ripened inhibition due to spermine decreased whereas that by calcium increased; (ii) inhibition by calcium was transitory, whereas that by spermine was persistent; (iii) at temperatures below 12°C calcium inhibited more than spermine whereas above 12°C the reverse was true. Temperature-dependence of the spermine and calcium effect on ethylene biosynthesis was correlated with specific changes induced by them in the microviscosity of microsomal membranes of apple tissue. Pretreatment with calcium resulted in lower microviscosity of the membranes compared to those of buffer-treated discs and in both cases microviscosity increased with increase in temperature of incubating solution containing fruit discs. Spermine stabilized membrane fluidity in apple discs incubated at temperatures above 4°C, thereby preventing the natural increase in microviscosity which occurred with increasing incubation temperature. These effects of calcium and spermine on membrane microviscosity required preincubation of fruit discs with the test compound since addition of spermine or calcium directly to microsomal membranes immediately before assay had no effect on their microviscosity.
72 citations
TL;DR: Leaf-protein analysis of two reciprocal hybrids of Nicotiana glutinosa × N. debneyi revealed that they contain a protein which is not normally present in the uninfected parent species, which may have a relationship to the high level of resistance to TMV in these plants.
Abstract: Leaf-protein analysis of two reciprocal hybrids of Nicotiana glutinosa × N. debneyi, grown either in a greenhouse or in vitro, revealed that they contain a protein which is not normally present in the uninfected parent species. This protein has the same charge and the same mol. wt. of 13 800 as the b1″ protein induced in N. glutinosa and in N. debneyi during the hypersensitive reaction to tobacco mosaic virus (TMV) and tobacco necrosis virus (TNV), respectively (Ah et al., Phytophatology, 72 (1982) 80); it is not present in root extracts. Both hybrids are highly resistant to TMV, as compared to N. glutinosa, even though they are heterozygote for the resistance gene (N) of this species. Following inoculation, they develop smaller local lesions, from which only an extremely low level of infectivity can be obtained, and at higher temperatures (31°C) no generalization of the TMV infection occurs after 2 days, in contrast to N. glutinosa. The presence of b-proteins as constitutive components in these interspecific hybrids and the different possible pathways leading to their appearance are discussed, together with their possible relationship to the high level of resistance to TMV in these plants.
TL;DR: A method is described which allows the determination of cell number in the wheat endosperm in the presence of large numbers of starch granules and the numbers of nuclei are estimated after deposition on millipore filters.
Abstract: A method is described which allows the determination of cell number in the wheat endosperm in the presence of large numbers of starch granules. Following fixation, heating water at 60°C for 10 min causes the starch granules to swell. After staining and cellulase treatment, the sample is macerated and then incubated with α-amylase which breaks down the granules. The numbers of nuclei are estimated in these samples after deposition on millipore filters. Such samples could be kept at room temperatures for at least 120 h without any reduction in the numbers of nuclei counted.
TL;DR: Efficient precocious germination of somatic embryos was dependent on the presence of 6-benzylaminopurine (BA) and naphthaleneacetic acid (NAA) in the growth medium.
Abstract: Carica papaya L. ovules were cultured on sterile White's medium modified by the addition of 60 g/l sucrose, 400 mg/l glutamine, 20% (v/v) filter-sterilized coconut milk and 8 g/l agar. Compact highly embryogenic calli were obtained from 10–20% of the cultured ovules after several weeks and were subcultured either on the same medium or on medium without coconut milk. Somatic embryogenesis occurred on both media, but at a much greater frequency on solid or in liquid White's medium without coconut milk. Efficient precocious germination of somatic embryos was dependent on the presence of 6-benzylaminopurine (BA) and naphthaleneacetic acid (NAA) in the growth medium. Plants have been successfully established in the greenhouse.
TL;DR: Protoplasts isolated from leaves of Nicotiana sylvestris show dramatic changes in their gene expression, which are in part due to the high osmotic strength of the isolation medium necessary to obtain viable protoplasts.
Abstract: Because protoplasts isolated from leaves of Nicotiana sylvestris show dramatic changes in their gene expression, the proteins they synthesized were compared to those synthesized by cells incubated in hypertonic or isotonic medium. These comparisons led to the conclusion that the changes are in part due to the high osmotic strength of the isolation medium necessary to obtain viable protoplasts. The protoplasts responded to this environmental change very much as other types of cells respond to stresses.
TL;DR: Indole-3-acetic acid in concentrations from 10 −12 M to 10 −9 M does not stimulate elongation when applied to intact roots of maize and suggests that auxin-induced ethylene biosynthesis may account, at least in part, for auxin inhibition of root growth at high concentrations and for the failure of auxin to stimulate intactRoot growth at low concentrations.
Abstract: Indole-3-acetic acid (IAA) in concentrations from 10 −12 M to 10 −9 M does not stimulate elongation when applied to intact roots of maize ( Zea mays L Bear Hybrid WF 9 × 38). Higher concentrations are inhibitory. In roots pretreated with the ethylene biosynthesis inhibitors, cobalt and aminoethoxyvinylglycine (AVG), IAA from 10 −10 M to 10 −8 M promotes growth. High concentrations of IAA (eg. 10 −6 M) strongly inhibit growth in either pretreated or non-pretreated roots. The data indicate that low concentrations of auxin are capable of stimulating the growth of intact roots in which ethylene biosynthesis is suppressed. This suggests that auxin-induced ethylene biosynthesis may account, at least in part, for auxin inhibition of root growth at high concentrations and for the failure of auxin to stimulate intact root growth at low concentrations.
TL;DR: In this paper, 1 mM sodium vanadate and 10 −4 M abscisic acid (ABA) were applied to Vicia faba epidermal peels.
Abstract: Summary Stomatal opening in isolated Vicia faba epidermal peels was blocked by 1 mM sodium vanadate and by 10 −4 M abscisic acid (ABA). Light-induced hydrogen ion release and potassium accumulation were also inhibited by vanadate. Vanadate-treated guard cells could still respond to fusicoccin (FC) after removal of the inhibitor. ABA inhibited light-induced guard cell opening within 20 min of treatment. ABA also prevented guard cell potassium accumulation, but only partially inhibited hydrogen ion release (~50%) during the first 90 min of treatment. The possible modes of action of vanadate and ABA are discussed.
TL;DR: A simple procedure is described for the aseptic manual isolation of individual heterokaryons, identified with bright field illumination using an inverted microscope and isolated by means of micro-manipulator and capillary pipette coupled to a specially constructed syringe.
Abstract: A simple procedure is described for the aseptic manual isolation of individual heterokaryons. Heterokaryons were identified with bright field illumination using an inverted microscope and isolated by means of a micro-manipulator and capillary pipette coupled to a specially constructed syringe. When cell suspension protoplasts were labelled with fluorescein isothiocyanate and fused with mesophyll protoplasts, the heterokaryons exhibited an apple green cytoplasmic fluorescence (from cell suspension protoplasts) and a red chloroplast fluorescence (from mesophyll protoplasts). By this double fluorescence procedure, these manually isolated heterokaryons, identified initially using brightfield could be confirmed as heterokaryons.
TL;DR: Three barley mutants, designated as R5201, R6102 and R6902, selected for resistance to 4 mM trans -4-hydroxyproline (Hyp) accumulated proline in the soluble fraction of the leaf to three times the normal amount.
Abstract: Three barley ( Hordeum vulgare L.) mutants, designated as R5201, R6102 and R6902, selected for resistance to 4 mM trans -4-hydroxyproline (Hyp) accumulated proline in the soluble fraction of the leaf to three times the normal amount. Resistance in each case was due to a single semi-dominant gene. Genetic analysis showed that the genes ( Hyp 1a, Hyp 1b and Hyp 1c ) in R5201, R6102 and R6902 were allelic. The response of R5201 to water- and salt-stress was compared with the parental cultivar Maris Mink. The growth of R5201 was less inhibited by low concentrations of NaCl (under 100 mM) and also under conditions in which the NaCl concentration was raised to 200 mM over a period of 3 days. At constant NaCl concentrations above 100 mM and in polyethylene glycol (PEG) (0–40%), the growth of R5201 and Maris Mink plants was equally inhibited.
TL;DR: The results showed that the method used for induction of adventitious buds strongly affected the ability of the induced buds to develop into vigorous adventitious shoots which could be rooted.
Abstract: A method is described for multiple shoot and plantlet formation on embryos of Picea abies (L.) Karst. Adventitious bud primordia were induced by culturing newly isolated embryos on media containing cytokinin. Further development of the bud primordia required transfer to cytokinin-free media. Adventitious shoots with a distinct stem were isolated from the embryos. After a couple of months the shoots were given a root-inducing treatment. When the roots had started to elongate the shoots were transferred to unsterile conditions. The capacity for bud production varied depending on the background of the seeds. The results showed that the method used for induction of adventitious buds strongly affected the ability of the induced buds to develop into vigorous adventitious shoots which could be rooted. The most critical factors which are discussed are: basal media concentration, cytokinin concentration, choice of cytokinins, and photoperiod.
TL;DR: It is proposed that external and internal injuries signal activation of an endogenous control mechanism which blocks the H + channel of the plasma-lemma ATPase and that FC acts to bypass the block.
Abstract: The electrogenic H + efflux of washed corn root tissue is completely inhibited by brief exposure to ice temperatures, hypertonicity and gentle rubbing. Fusicoccin (FC) will partially restore the H + pumping, and an uncoupler will nullify the effect of FC. Oligomycin and ethidium bromide, known to block H + transport by mitochondrial ATPase, will very rapidly block H + efflux from roots and FC will partially restore it. The previously reported inhibition of H + efflux by protein synthesis inhibitors occurs before amino acid incorporation is much affected. Use of the pH indicator dye, bromocresol purple, shows that cutting injury leads to H + influx in cells around the wound surface; cold shock leads to a general H + influx. It is proposed that external and internal injuries signal activation of an endogenous control mechanism which blocks the H + channel of the plasma-lemma ATPase and that FC acts to bypass the block.
TL;DR: In this paper, active uptake of nitrate into barley seedlings ( Hordeum vulgare L. cv. Fergus) was examined over the concentration range 0-0.6 mM NO 3 − in relation to the nitrate concentration during the previous growth period.
Abstract: Active uptake of nitrate into barley seedlings ( Hordeum vulgare L. cv. Fergus) was examined over the concentration range 0–0.6 mM NO 3 − in relation to the nitrate concentration during the previous growth period. The highest rate of uptake was found when plants were grown at 10μM NO 3 − at which concentration there was no net uptake (nitrate compensation point). Furthermore there was no lag in NO 3 − uptake from test solutions. There was no apparent relationship between rates of nitrate uptake and hydroxyl efflux; moreover, when seedlings which had been grown at the NO 3 − compensation point were used some acidification of the uptake medium occurred. The uptake of both 45 Ca 2+ and 86 Rb + into barley seedlings was independent of the nitrate concentration of the external media and thus did not account for the discrepancy between NO 3 − uptake and OH − efflux. The hypothesis that alkalinization during NO 3 − uptake is related to nitrate reduction rather than uptake is put forward.
TL;DR: The large contents of DGTS in Ochromonas and Chlamydomonas parallel low contents of phosphatidyl choline (PC), from this it is suggested that DGTS may substitute for PC in these algae.
Abstract: Diacyglyceryl- O -4′-( N , N , N -trimethyl) homoserine (DGTS), a lipid which is typical of Ochromonas (Chrysophyceae) and Chlamydomonas (Chlorophyceae), has also been detected in Polytoma and Fritschiella (Chlorophyceae), but not in Chlorella and Prototheca (Chlorophyceae), Euglena (Euglenophyceae) and Fucus (Phaeophyceae) The large contents of DGTS in Ochromonas and Chlamydomonas parallel low contents of phosphatidyl choline (PC) From this it is suggested that DGTS may substitute for PC in these algae DGTS is formed by algae of different taxonomic positions and by both photosynthesizing and non-photosynthesizing species A correlation between the presence of DGTS and cellular organization has not been detected
TL;DR: In this paper, Shamouti cells of "Shamouti" (Citrus sinensis Osb.) capable of growing in the presence of 0.2 M NaCl were obtained by exposure of the cultured cells to a medium containing salt.
Abstract: Callus cells of ‘Shamouti’ (Citrus sinensis Osb.) capable of growing in the presence of 0.2 M NaCl were obtained by exposure of the cultured cells to a medium containing salt. The growth curve of the selected salt-tolerant line (R-10) in the presence of NaCl showed a prolonged lag period, slightly slower rate of increase in fresh weight and about 50% yield as compared with the situation in the absence of salt. However, non-selected cells (L-5) did not grow in the presence of 0.2 M NaCl. The increased tolerance for salt of the R-10 cell line was retained after four consecutive transfers in medium without salt. This stability indicates that during the selection procedure a true genetic variant was isolated. R-10 cells selected for tolerance towards NaCl were also tolerant to other sodium salts.
TL;DR: Findings are consistent with the acid-growth theory of auxin action and provide further evidence that the decrease in the mass-average MW of the cell wall xyloglucans is involved in the critical process responsible for the auxin-induced cell extension growth.
Abstract: Summary Acid pH, like indole-3-acetic acid (IAA), induced a decrease in the mass average molecular weight (MW) of xyloglucans in the hemicellulose fraction when it induced cell wall loosening and cell extension of epicotyl segments of light-grown Vigna angularis Ohwi et Ohashi cv. Takara seedlings, The effect of acid pH on the xyloglucan appeared without a lag period and the molecular weight decreased linearly with time in acidic pH solution. This effect of acid pH on the xyloglucan was completely reversed by subsequent treatment with neutral pH solution. These findings are consistent with the acid-growth theory of auxin action and provide further evidence that the decrease in the mass-average MW of the cell wall xyloglucans is involved in the critical process responsible for the auxin-induced cell extension growth.
TL;DR: Protoplasts isolated enzymatically from roots of germinating soybean seeds divide to form callus and the ability to culture protoplasts of a more meristematic type is discussed with respect to genetic manipulations in this crop species.
Abstract: Protoplasts isolated enzymatically from roots of germinating soybean seeds divide to form callus. The ability to culture protoplasts of a more meristematic type is discussed with respect to genetic manipulations in this crop species.
TL;DR: Growth during recovery of water-stressed barley plants was enhanced by proline and betaine treatments, while no effect on growth during stress was noted Cucumber plants were not similarly affected by Proline, although it was taken up by the plants as mentioned in this paper.
Abstract: Growth during recovery of water-stressed barley plants was enhanced by proline and betaine treatments, while no effect on growth during stress was noted Cucumber plants were not similarly affected by proline, although it was taken up by the plants
TL;DR: The drastic effect of antimycin A on the release of peroxidase indicates the need of energy for transport to proceed, probably via the Golgi apparatus.
Abstract: The major increase of peroxidase activity in the medium of a suspension culture of peanut ( Arachis hypogaea , L) cells occurs between day 4 and 9 of a biweekly subculture period. This assumed release of peroxidase into the medium parallels the period of most active peroxidase synthesis in these cells. The biosynthesis and subsequent release of peroxidase were monitored more precisely by the incorporation of [ 35 S]methionine and immunoprecipitation with antibodies raised against the most abundant peroxidase isozyme. Pulse-chase experiments were used to illustrate the transport system. The drastic effect of antimycin A on the release of peroxidase indicates the need of energy for transport to proceed, probably via the Golgi apparatus.
TL;DR: The contention that nocturnal malic-acid accumulation in the vacuoles of crassulacean acid metabolism (CAM) plants is an energy-dependent process was confirmed by experiments on excised phyllodia with the inhibitors 2,4-dinitrophenol, m-chlorocarbonylcyanide phenylhydrazone and diethylstilbestrol.
Abstract: The contention that nocturnal malic-acid accumulation in the vacuoles of crassulacean acid metabolism (CAM) plants is an energy-dependent process was confirmed by experiments on excised phyllodia of Kalanchoe tubiflora with the inhibitors 2,4-dinitrophenol (DNP), m-chlorocarbonylcyanide phenylhydrazone (CCCP) and diethylstilbestrol (DES). Levels of ATP, ADP and Pi were also measured in bulk-tissue extracts of phyllodia during the normal CAM rhythm. ATP levels increased during the dark period and decreased during the light period, whereas ADP and Pi levels did not show any significant changes. In some plants the ATP levels started to decrease before the end of the dark period. It is suggested that the changes in ATP levels are a reflection of the changing flux through glycolysis towards malate in the dark period. The results were used to estimate the free energy available from ATP hydrolysis (ΔGATP), which was compared with the H+-electrochemical potential difference ( Δ μ H + ) across the tonoplast. This permitted consideration of the stoichiometry of the H+-ATPase that is postulated to be responsible for malic-acid accumulation in the vacuole.
TL;DR: The induction of sustained cell divisions and of cell colony formation also seemed to depend on the physiological condition of the seedlings and on the progenies used as starting material for the isolation of protoPlasts.
Abstract: Summary Mesophyll protoplasts were isolated from leaves of Alnus glutinosa (L.) Gaertn. and A. incana (L.) Moensch using enzymatic digestion of cell walls. The protoplasts slowly synthesized new cell walls and 5–10% of the cells divided after 3 weeks. Ornithine (0.025 mM) and putrescine (0.05 and 0.1 mM) were found to stimulate cell division and colony formation in both Alnus species tested. A low concentration of spermidine (0.025 mM) induced slight cell division in A. glutinosa , but spermine and higher concentrations of spermidine were inhibitory and no cell colony formation was observed. The induction of sustained cell divisions and of cell colony formation also seemed to depend on the physiological condition of the seedlings and on the progenies used as starting material for the isolation of protoPlasts. After the cell colonies had been transferred to agar media with the same composition as the media inducing cell divisions, but lacking mannitol, the protoplasts of two A. glutinosa progenies formed actively growing calluses, which turned green in light.
TL;DR: A combination of cold pretreatment and high temperature shock was essential in inducing embryogenesis in cultured anthers of Brassica juncea var.
Abstract: Pollen embryogeny was induced in cultured anthers of Brassica juncea var. TM-4. A combination of cold pretreatment and high temperature shock was essential in inducing embryogenesis. Pollen grains developed directly into embryos on a high sucrose medium. However, further growth of the embryos was not normal and resulted in abnormal plantlets. From the abnormal plantlets obtained in vitro, hypocotyl explants were excised and were induced to regenerate numerous shoot buds on a medium supplemented with NAA and BA. The shoot buds developed into normal plants. Among the population of pollen plants both haploids and diploids were observed.