摘要:

The roles of phytohormones and fusicoccin in H+extrusion by isolated protoplasts from rape leaves (Brassica napusL. cv. Belinda) were investigated and compared to results obtained with leaf segments of the same plants. Net H+release by protoplasts, which was at least partly due to ATPase activity, was enhanced by 10 μMindole‐3‐acetic acid and reduced by 20 μMabscisic acid, whereas fusicoccin (10 μM), brassinosteroid (3 μM), kinetin (20 μM) and gibberellic acid (10 μM) had no effect. Hormone effects and H+release were not detectable with leaf segments from the same plants. However, using field‐grown plants, indole‐3‐acetic acid and especially fusicoccin stimulated the acidification of the external medium by leaf segments. Hormonecontrolled H+release by leaf cells is interpreted as the first step in acid‐triggered and turgor‐re

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb03341.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Since ferredoxin‐dependent sulfite reductase (EC 1.8.7.1) and nitrite reductase (EC 1.7.7.1) can both catalyze the reduction of SO2‐3and NO−2, physiological and biochemical evidence is needed for properly classifying the two enzyme activities. They were therefore compared during ontogeny of pea leaves and in the effect of their products, sulfide and ammonium, on their catalytic activity. In the crude extract of the young second leaf of pea plants,Pisum sativumL. cv. Vatters Frühbusch, no ferredoxin‐nitrite reductase activity could be detected, but ferredoxin‐sulfite reductase and ATP‐sulfurylase (EC 2.7.7.4), measured for comparison, were at 24 and 14%, respectively, of their maximal activity per leaf. After 11 and 12 days, respectively, ATP‐sulfurylase and ferredoxin‐sulfite reductase were no longer detectable, whereas ferredoxin‐nitrite reductase was still at more than 30% of its maximal activity per leaf. Ferredoxin‐sulfite reductase was inhibited by 50% with 18 μMand 100% with 30 μMsulfide produced by this enzyme during its assay. Sulfide at 100 μMadded to the assay mixture completely inhibited ferredoxin‐sulfite reductase activity in the crude extract, the 30000 g pellet and its supernatant. The same addition reduced ferredoxinnitrite reductase activity by 20% in the crude extract and by 100% in the 30000 g pellet. NH+4at 100 μMdid not affect ferredoxin‐sulfite reductase or ferredoxin‐nitrite reductase activity.The inhibition by sulfide and the changes in activity during ontogeny similar to ATP‐sulfurylase (which catalyzes the first step of assimilatory sulfate reduction) represent biochemical and physiological evidence for the correct classification of ferredoxin‐sulfite reductase. The complete inhibition of ferredoxin‐nitrite reductase activity in the 30000 g pellet by S2‐indicates that this activity was

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb03342.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Net photosynthesis, transpiration, dark respiration rates and stomatal and mesophyll resistances were studied in young potted seedlings ofPinus halepensisMill. under gradually decreasing soil and leaf water potentials. Stomatal resistance under non‐limiting xylem water potentials was 6–7 times higher than mesophyll resistance. Stomata started to close at threshold xylem water potentials of −0.8 MPa, whereas mesophyll resistance started to increase at about −1.4 MPa. Decreasing xylem water potentials increased the CO2compensation point and decreased the water use efficiency (expressed by the photosynthesis to transpiration ratio) and dark respiration rate. It is concluded that at least part of the drought resistance characteristics ofP. halepensisare associated with a sensitive stomatal mechanism which enables an efficient control of wat

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb03343.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Four major basic proteins termed C, K, N and Q, which are synthesized very late in grain development, have been isolated from barley (Hordum vulgareL.) mutant Bomi 1508. Immunoelectrophoretic monitoring assured a high degree of purity after a few ion exchange and gel filtration steps. Charge microheterogeneity of two of the four antigenically distinct proteins was observed. Some physico‐chemical properties were determined, including molecular mass (C ∼ 28 000; K ∼ 30 000; N ∼ 11 000; Q ∼ 60000), isoelectric point(s) (C ∼ 9.7; K ∼ 10.1–10.3; N ∼ 9.3; Q ∼ 8.9–9.1 at 25°C), and amino acid composition. In total, the four proteins represent ∼ 5% of the salt‐soluble protein in grains of some cultivated barleys. The most basic protein K is rich in lysine (∼ 7.9 mol %) and may account for ∼1% of the grain l

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb03344.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The response ofSuaeda aegyptiaca(Hasselq.) Zoh. to various salinity treatments was tested in sand culture. Growth was promoted by NaCl and by Na2SO4at all tested concentrations, but not by KCl. The effect of NaCl on growth was stronger than that of Na2SO4and it increased gradually up to a 125 eq. m−3optimum. Ion uptake was also affected by the different salts. Cl−was taken up in similar quantities from KCl and from NaCl solutions and the content of the respective cations was also similar to one another. The presence of Na+in the medium lowered the content of K+in the plants and at the same time increased growth by as much as 900%. Transpiration was reduced and water use efficiency increased by Na+‐salts. Highest water use efficiency was exhibited by plants which were treated with 125 eq. m−3NaCl. It is concluded that Na+at the macronutrient level has a specific promotive effect on the physiological processes ofS. aegyptiaca.This effect is not due to replacement of K+by Na+; neither can it be achieved by increasing the K+concentration. Cl−has an additional positive effect on growth of S.aegyptiaca.This effect is only expressed in the presen

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb03345.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The effects of ethylene and auxin on the morphology and anatomy of root organ cultures ofPinus mugoTurra var.mugowere investigated to test the hypothesis that changes in root morphology associated with formation of ectomycorrhizae may be related to ethylene produced by ectomycorrhizal fungi or by host plant roots in response to fungus‐produced auxin. Morphological changes characteristic of mycorrhizal infection include dichotomous branching of lateral roots, inhibition of root hair formation and enlargement of cortical cells. Lateral roots on non‐mycorrhizal root organ cultures, grown in a defined medium, underwent dichtotomous branching while root hair formation was inhibited in response to the ethylene released by 50 and 100 μMethephon (2‐chloroethylphosphonic acid), but no effect on cortical cell dimensions was observed. The auxin, naphthaleneacetic acid (1 and 10 μM) also stimulated dichotomous branching and inhibited root hair formation, but to a lesser extent and with a greater lag time than ethephon. Auxin‐stimulated ethylene production by root organ cultures was demonstrated. This appeared to be responsible, at least in part, for the auxin‐induced dichotomous branching since the ethylene action inhibitor, silver thiosulfate (0.1 mM) inhibited the response to a

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb03346.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The effect of light on anthocyanin production in apple (Malus pumilaMill. cv. Jonathan) skin disks was investigated, with prolonged irradiation from different light sources. High fluence rates of white light provided from a xenon lamp were unable to produce large amounts of anthocyanin, and anthocyanin production became saturated at about 30 W m−2. When UV‐B light, provided by a fluorescent lamp which had an emission peak at 312 nm, was combined with the white light, anthocyanin production was synergistically stimulated and increased up to the highest fluence rates of white light tested (44 W m−2). This UV‐B light was more effective than red and blue light provided from fluorescent lamps, but anthocyanin production became saturated at about 1.7 W m−2. However, simultaneous irradiation with red and UV‐B light had a synergistic effect. UV‐B light was also effective in increasing anthocyanin production in whole fruit. Therefore this synergism seemed to have an important role in the development of the desirable red skin color under field light conditions. The results of aminoethoxyvinylglycine treatment suggested that ethylene was not involved in the stimulative effect

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb03347.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Cytokinin‐like activity in extracts of leaf laminae, petioles, shoots, roots and flowers of young plants of the water hyacinth,Eichhornia crassipesS. was analyzed following Sephadex LH‐20 column chromatography using the soybean callus bioassay. In all plant parts analyzed, two prominent peaks of cytokinin activity having elution volumes similar to zeatin and zeatin riboside were detected. Putative cytokinin gluco‐side‐like activity was detected only in leaves and flowers. The cytokinin complements of the leaves and the roots were qualitatively different. It would appear that cytokinins supplied by the roots are metabolized in the leaves or certain cytokinins are synthesized in the leaves themselves. The possible significance and distribution of cytokinins in different plant parts in relation to roots is di

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb03348.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Freezing or desiccation of winter rape leaves (Brassica napusL. var.oleifera(cv. Górczanski) stimulated both lipoxygenase (EC 1.13.11.12) activity and ethylene formation during the post‐stress period. The effect depended on the degree of membrane injury. In tissues showing injury less than 50% (as checked with the electrical conductivity method) both activities increased according to the degree of stress‐induced damage. In leaves injured to a higher degree both activities decreased. Light and low temperature (5°C) inhibited the development of both lipoxygenase activity and ethylene formation in leaf disks stored for 20 h. Ethylene formation was also observed in a model system where soybean lipoxygenase was added to a mixture containing 1‐aminocyclopropane‐1‐carboxylic acid and linoleic or linolenic acid as substrate for lipoperoxide formation. Changes in pH and temperature conditions of the incubation mixture caused similar differences in the lipoxygenase activity and ethylene formation. We propose that the stimulation of lipoxygenase‐catalysed oxidation of polyunsaturated fatty acids (increasing free radical formation) leads to an increased ethylene produc

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb03349.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Clones ofRosa damascenaMill. cv. Gloire de Guillan, selected for growth in solid medium containing 56 mMNaClO3, were studied to determine the reason for their resistance to this toxic salt. The cells grew on medium containing nitrate as the only nitrogen source, and they synthesized nitrate reductase (EC 1.6.6.2) in the presence of nitrate. The cells were resistant in the presence of nitrate. However, their resistance was greatly increased by the presence of glutamate in the medium. The cells took up [36Cl]‐ClO3‐ and reduced it to ClO2−, but the fraction of ClO3−that they reduced under our experimental conditions was less than that reduced by wild type. The slower production of ClO2−apparently accounted for the resistance of the cells to ClO3−. We suggest several possible reasons for the low rate of reducti

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1985.tb03350.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY