摘要:

The herbicide endothall (7‐oxabicyclo 2.2.1 heptane‐2, 3‐dicarboxylic acid) was applied to cotton (Gossypium hirsutumL. cv. Acala SJ‐1) cotyledon discs. Treatment with 10−4Mendothall for 24 h resulted in injury which was expressed by increased leakage of electrolytes, development of necrotic areas, increased level of polyphenols and tissue browning. We examined whether treatments which decrease chilling injury would also decrease injury caused by the herbicide. Tissue from seedlings grown at 28°C was more sensitive to endothall than that from seedlings grown at 15°C. Pretreatment with 10−5Mabscisic acid greatly decreased the leakage of electrolytes, necrotic areas, and tissue browning caused by endothall. Similar pretreatment did not prevent the increase of polyphenols caused by the herbicide. The treatment with abscisic acid was more effective in protection against the herbicide injury when applied several hours prior to the herbicidal treatment. This time requirement indicates that the mechanism by which abscisic acid induces resistance to the herbicide depends, at least partially, on active metabolism. We suggest that the increased resistance to herbicide stress by abscisic acid is another example of a common resistance mechanism to various stresses in which abscisic aci

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00751.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Following ion‐exchange, Sephadex LH‐20 and paper chromatography of the methanolic extracts of young, developing fruits ofAegle marmelosCorrea, cytokinin‐like activity in the soybean callus assay was detected in six fractions. Of the four butanol‐soluble compounds, two were tentatively identified as zeatin and zeatin riboside, and the others as zeatin glucoside and zeatin riboside glucoside. The major cytokinino of the butanol‐insoluble fraction is probably zeatin nucleotide. The levels of compounds with cytokinin‐like activity were high during the early phase, and low in the subsequent period of fruit growth. The activity resembling that of cytokinin glucoside increased with maturation of the fruit. The content of free cytokinins in the fruits was more than that released fr

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00752.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Apple trees (Malus pumila Mill. var.domesticaFuji/Malus prunifoliarootstock) showed a high susceptibility to bitter pit when supplyed with ammonium salt instead of nitrate (control) in the nutrient solution. When apple fruit was affected by bitter pit, a lower calcium as well as a higher nitrogen and ammonium‐nitrogen contents was observed in the fruit flesh near the calyx end. The activity of the mitochondrial Ca2+‐uptake of the fruit flesh near the calyx end was higher when the tree was grown with ammonium salt than when grown with nitrate. Both the activities of succinate: cytochromecoxidoreductase and the mitochondrial Ca2+‐uptake per g of tissue were higher in affected fruit than in healthy fruit. Each of chlorpromazine, N‐(6‐aminohexyl)‐5‐chloro‐l‐napthalenesulfonamide (W‐7) and N‐(6‐aminohexyl)‐l‐naphthalenesulfonamide (W‐5), calmodulin antagonists, was infiltrated into the fruit for 20 min under reduced pressure (about 1 × 104Pa). Few days later, numerous bitter pit‐like spots were observed in both fruit treated with W‐7 and chlorpromazine, while only a few spots were observed after the infiltration with W‐5, a less potent calmodulin antagonist. A possible mechanism for the o

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00753.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The membrane potential in highly coupled potato (Solanum tuberosumL.) mitochondria, as measured by changes in safranine absorbance, was significantly increased by addition of bovine serum albumin. Purification of potato mitochondria on Percoll, in removing 50% of free unsaturated fatty acids, decreased the BSA‐de‐pendent membrane potential. The effect of added linoleic acid and of the natural accumulation of fatty acids during aging was studied. The response of membrane potential to addition of bovine serum albumin appeared to be directly correlated to the amount of free unsaturated fatty acids. Aging in vitro, in releasing free fatty acids, decreased respiratory control and ADP:O ratios and collapsed the membrane potential. During 2–3 h of incubation, addition of BSA completely restored membrane potential and oxidative phosphorylation.It is concluded that both in fresh and in aged potato mitochondria the effect of bovine serum albumin on oxidative phosphorylation can be ascribed to an effect on membrane permeability to ions. BSA, in binding free unsaturated fatty acids, restored maximal membrane potential. The bovine serum albumin‐dependent membrane potential appears to be a sensitive criterion of the functional integrity of the inner mitochondrial m

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00754.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Pitiuba bean [Vigna unguiculata(L.) Walp.] seeds were sown in water or. in 0.1MNaCl. Seedling growth and cotyledon nucleic acid mobilization were delayed by NaCl salinity. The differences in cotyledonary RNase activity between seeds sown in water and in NaCl solutions suggest that salinity delays the activation and/or de novo synthesis of the enzyme. Cotyledon extracts were subjected to gel filtration through Sephadex G‐100, and RNase activity measured. Only one cotyledonary RNase appeared during germination, and salinity did not induce any change in molecular weight of the enzyme. Salinity inhibited 45% of the specific activity of the RNase on the 5th day of the experimental period. The same salt concentration (0.1MNaCl) added in vitro inhibited only 8 % of the specific activity of the enzyme. This difference may indicate that NaCl in vivo affects mainly the de novo synthesis of the RNas

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00755.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Visual damage is commonly used as the criterion for assessment of salinity resistance in rice breeding programmes. The use of other indicators, such as sodium uptake, is being evaluated: a correlation between initial sodium uptake to the third leaf and varietal survival was established and the physiological basis of this examined.Chlorophyll was used as an indicator of metabolic status and the relationship between leaf sodium and chlorophyll concentrations investigated for nine varieties differing in their resistance to salinity. By sampling a population of leaves having a wide range of salt concentrations, inverse relationships between chlorophyll and sodium concentrations were established. The salt concentration in the leaf tissue which causes equivalent toxicity (50% loss of chlorophyll) differed 3‐fold amongst these varieties. Varieties showing the greatest tolerance to salt within the leaves were not necessarily those showing the greatest overall phenotypic resistance to salinity.The enzymes malate dehydrogenase and nitrate reductase were activated equally by sodium and potassium ions at 60–80 mol m−3in both control and saline grown plants and severely inhibited at higher concentrations. If all the salt in the tissue of leaves with 50% chlorophyll remaining was in solution and uniformly distributed the concentration would be 135–500 mol m−3. This is improbable and some level of compartmentation is likely.It is concluded that while initial sodium uptake has predictive value for salinity resistance of varieties, there are other characteristics which are masked by excess salt entry and require independent assessment; no single factor confers r

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00756.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Iron‐deficient bean plants (Phaseolus vulgarisL. cv. Prélude) exhibited a ferric reducing activity in the roots, with kinetics characteristic for matrix‐bound enzymes: the reaction rate was proportional to substrate (Fe‐EDTA) concentration until 100 μM, and at higher concentrations it leveled off to a maximum; the Lineweaver‐Burk plot yielded a non‐linear relationship between rate−1and substrate−1. The Arrhenius plot yielded apparent activation energies which were dependent on substrate concentration. No evidence was obtained for the secretion by roots of a low molecular weight metabolite involved in the reduction of iron prior to its uptake. The results are interpreted to indicate that the ferric reducing activity in the roots of iron‐deficient bean plants is located in an enzyme in the plasmalemma of the cortex o

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00757.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The relationship between the inhibiting effect of Ca2+and of low turgor pressure on K+release from fresh‐cut discs of carrot (Daucus carotavar. Nantes) storage tissue was studied. A range of Ca2+concentrations in the tissue was obtained by adding 0.5 mMEDTA or CaSO4at different concentrations to the medium. Calcium inhibited K+release in fully turgid cells (2.5 μmol K+g−1h−1in 0.5 mMEDTA vs 0.4 μmol K+g−1h−1in 10 mMCaSO4). Less turgid cells, obtained by equilibration with 0.2Mmannitol, released K+at only 30% of the rate of the turgid cells, yet the pattern of K+release as a function of Ca2+level was similar in both turgid and non‐turgid cells. Removal of calcium by EDTA occasionally injured cell membranes in the fully turgid discs but never in the less turgid ones. In view of the additive effect of Ca2+and low turgor on K+release regardless of the treatment order, it is suggested that the two factors exert their effect on membrane permeability independently

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00758.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

The effect of abscisic acid (ABA) was observed on exudation from roots of sunflower (Helianthus annuusL. cv. Habad) plants whose mineral nutrition was cut off or which were deprived of K+or NO−3for 90 h prior to excision. In spite of a marked decrease in exudation rate, the magnitude of the promotive effect of ABA on both volume flow and release of ions to the xylem was similar to that obtained in roots of plants grown in full nutrient solution. Application of ABA to the medium at different times after excision increased the promotive effect of ABA as the time from excision increased. The magnitude of the ratio ABA‐treated/control in roots which were treated 74 h after excision was twice that in freshly‐excised roots. The effect of ABA lasted up to 50 h and during that period it followed the endogenous rhythm in exudation from the control roots. It is concluded that since a steady promotive effect of ABA persists under a variety of experimental conditions, this may be considered a genera! phenomenon in sunflower

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00759.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Tomato (Lycopersicon esculentumMill.) plants of the non‐ripening mutantnor(3rd backcross to the normal cultivar Rutgers) were grown under water stress induced in two different ways: a) reduction of water supply and b) increase in transpiration rate by adding kinetin to the nutrient solution. Both drought treatments induced fruits of the non‐ripening mutantnorto ripen, that is, the parameters characteristic of ripening – red pigment, taste, pectolytic activity, softening, and the evolution rates of CO2and ethylene – all increased, although not to the normal level. Such an increase does not normally take place in thenormutant under control conditions. It is suggested that fruits of the nor mutant can be induced to ripen by any kind of water stress. The induction mechanism is still to be e

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1983.tb00760.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY