摘要:

Protoplasts ofBrassica napusL. were cultured individually in a microdroplet system using a synthetic medium with survival rates of more than 70% and division frequencies of up to 65%. Microcallus formation occurred at frequencies of up to 50%. Factors affecting the survival and division of individually cultured protoplasts, such as composition and volume of culture medium, pH, buffering system, osmolarity and genotype, were analyzed.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb01223.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Two cultivars of oat (Avena sativaL. cvs Pendek and Stormogul II) were exposed to short periods of water‐deficit stress on five consecutive days. The plants responded to the stress by decreasing their cuticular transpiration rate. After two stress periods the cuticular transpiration rate was reduced by 30% for Pendek and by 47% for Stormogul II, and after another three stress periods by 30% and 20%, respectively. These reductions were correlated neither to changes in the total amount of what is generally called epicuticular lipids, nor to changes in any of the major individual constituents of the epicuticular lipids (alkanes, free and esterified fatty acids or free primary alcohols). After removal of the epicuticular lipids the long chain free primary alcohols of the leaves were extracted and determined. The amount of these presumably intracuticular alcohols increased after stress and changed to shorter chain length. From these results it is concluded that the intra‐ as well as the epicuticular lipids must be taken into consideration when discussing leaf surface lipids as protecting agents against water l

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb01224.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Hydroxycinnamic acidesters andphotoperiodic flowering induction in vitro ofCichorium intybus.In root tissues ofCichorium intybusL. cv. Witloof cultured in vitro, the photoinductive period occurs between the 8th and the 16th day after the start of the culture. The promotive light conditions are either long days (16 h photoperiod) or daily cycles of 9 h white + 15 h red light applied during the photoinductive period in an otherwise short day treatment. During the photoinductive period and under suitable irradiation conditions, the endogenous hydroxycinnamic acid esters (especially chlorogenic acid) show a regular development as from the 8th day, reaching a maximal level by the 16th day. The amount of these molecules then decreases rapidly, preceding the external expression of floral induction. When we apply non‐inductive conditions [short days (9 h) or daily cycles of 9 h white + 15 h (far‐red + red) light supplied from the 8th to the 16th day in otherwise short day conditions], the metabolic changes indicate the same pattern during the inductive period as mentioned above. However, a fundamental difference exists between the inductive and non‐inductive conditions, so that the production of hydroxycinnamic acid esters is particularly high towards the end of the second week of in vitro development in the induced state. This increase is not primarily due to increased photosynthetic activity in long day conditions, since it occurs both in the long day treatments and in the treatments with daily cycles of 9 h white + 15 h red light, thus revealing the morphogenetic action of light via phytochrome. This accumulation of hydroxycinnamic acid esters is correlated with floral induction, which appears to be ineffective unless there is a certain minimum amount of these molecules in the ti

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb01225.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Long‐distance transport in plants requires precise knowledge of vascular pathways, and these pathways differ among species. This study examines the14C translocation pathways in honeylocust (Gleditsia triacanthosL.) and green ash (Fraxinus pennsylvanicaMarsh.), species with compound leaves, and compares them with those of cottonwood (Populus deltoidesBartr. ex Marsh.), a species with simple leaves. The stem vasculature of honeylocust conforms to a 2/5 helical phyllotaxy and that of green ash to a decussate phyllotaxy. The plastochron is relatively long in both species – 2.5+ days in honeylocust and 4.5+ days in green ash. Consequently, the transition from upward to downward translocation from mature source leaves is abrupt and occurs close to the apex. Export of14C from localized treatment positions within a leaf was found to vary both quantitatively and spatially. To determine export patterns,14CO2was administered to either individual leaflets of once‐pinnate or pinnae of bipinnate leaves of honeylocust, and to either individual veins of simple or leaflets of compound leaves of green ash. Transections of either the petiole or rachis base were then examined for14C by micro‐autoradiography. In all cases, as treatment positions advanced acropetally in the leaves, the bundles translocating14C were situated more dorsally in the basal petiole and rachis vasculatures.14C was confined to the right side of the vasculature when structures on the right side of a leaf were treated. Compound leaves of both species mature acropetally. Thus, mature basal pinnae of honeylocust and basal leaflets of green ash translocate acropetally to younger leaf parts that are still rapidly expanding. All translocation pathways, both in the stem and leaf, conformed with vascular organization previously determined by anatomical a

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb01226.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Hot pepper (Capsicum annuumL. cv. Chooraehong) fruit underwent a respiratory climacteric during ripening. However, the rate of ethylene production was low, reaching a maximum of approximately 0.7 μl kg−1h−1at the climacteric peak when the surface color was 30 to 40% red. Ripening was accompanied by a loss of galactose and arabinose residues from the cell wall. The content of uronic acid and cellulose in the wall changed only slightly during ripening. The average molecular weight of a cell wall hemicellulosic fraction shifted progressively toward a lower molecular weight during ripening. Total β‐galactosidase (EC 3.2.1.23) activity increased 50‐fold from the immature green to the red ripe stage. No polygalacturonase (EC 3.2.1.15) activity was detected at any stage of ripeness. Thus, the loss of galactose and arabinose residues from the cell wall, as well as the observed modification of hemicelluloses during ripening, seem to be unrelated to active polygalacturonase. Soluble polyuronide content remained relatively constant at approximately 60 μg (g fresh weight)−1as fr

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb01227.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Long‐ or short‐term far‐red light given before a dark treatment modified the water status and the potassium and malate contents in cotton (Gossypium hirsutumL. cv. Bou) leaves. Upon a long‐term treatment, the leaf water content and the leaf water and osmotic potentials were lower whereas stomatal resistance was greater with a decrease in daily transpiration. There was a parallel increase in potassium and malate, but the calcium content was not significantly changed. This resulted in better water economy with an increase in drought resistance. Upon a short‐term treatment, the accumulation of potassium and malate was reversible and the drought resistance was modified accordingly. There was a positive correlation between the ability of a plant to resist water stress and the content of potassium a

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb01228.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Excised cotyledons of radiata pine (Pinus radiataD. Don) were cultured in the presence or absence of benzyladenine and two concentrations of dicyclohexylamine, a potent inhibitor of spermidine synthesis in animals and bacteria. Cellular levels of the drug and of putrescine, spermidine and spermine were determined by dansylation followed by thin layer chromatography. The rate of uptake of the drug was rapid during the first 6 h of incubation and then diminished; nevertheless, its cellular content increased with time in culture and uptake was greater if more was present in the medium. Cotyledons cultured on benzyladenine‐containing media accumulated more dicyclohexylamine than on benzyladenine‐free media and this resulted in toxic side‐effects. The drug had no significant effect on the elongation growth occurring in the absence of the hormone. In cotyledons treated with the drug, spermidine levels fell to zero after a 5‐ to 10‐day exposure. Putrescine increased transiently at 24 h and then declined significantly. Spermine levels also declined to 11% of control values by day 5 and remained low throughout. Except for a marked decrease in all three polyamines during the first 24 h of culture, all control cotyledons maintained significantly higher polyamine levels than dicyclohexylamine‐t

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb01229.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

A wild pea (Pisum sativumL.) native to Afghanistan normally known to be resistant to nodulation with European strains ofRhizobium leguminosarumwas nodulated early and effectively in field soil in Denmark. Isolates from nodules formed effective nodules abundantly on ‘Afghanistan’ on reinfection under aseptic conditions. Five types differing in isoenzyme composition pattern were found among 15 isolates from ‘Afghanistan’ nodules. None were identical with the ‘Tom’ strain from Turkey, which also forms effective nodules with ‘Afghanistan’. The five types were also different with respect to isoenzyme pattern fromRhizobium leguminosarumstrains isolated from a modern pea variety cultivated in

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb01230.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

A relatively high concentration of 2,4‐dichlorophenoxyacetic acid (45 μM) in solid culture medium stimulated the formation and secretion of mucilage polysaccharides by callus tissues ofArabidopsis thalianaL. Heynh. (line Estland). The mucilage was composed of at least two polysaccharides as revealed by gel chromatography on Sepharose 4B: the major component (87%) eluted in the void volume (molecular weight 2 × 106or greater) and the minor component (13%) eluted in the molecular weight range from 2 × 104to 4 × 105. Both polysaccharide components contained small amounts of uronic acids. The major polysaccharide consisted mostly of galactose (49%), arabinose (28%) and fucose (10%), whereas the minor one consisted of galactose (44%), xylose (18%), arabinose (14%) and rhamnose (14%). One of the components of the secreted mucilage seems to be an arabinogal

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb01231.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

The rate of oxygen uptake was measured on sections of mature leaf tissue derived from two populations ofLolium perenneL. cv. S23, selected for contrasting rates of mature leaf respiration. Under conditions of sufficient nutrient supply, GL72 had a lower rate of respiration and a greater yield than GL66. The populations were exposed to important management variables to investigate their effect on the selection criterion, the two variables being nutrient supply and defoliation. Conditions of low nutrient supply were characterized by a similarity in respiration rate and a change in the regulation of respiration. Enzyme levels, rather than adenylates, controlled respiration. Weekly cutting induced activity of the otherwise latent alternative pathway.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1986.tb01232.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY