摘要:

AbstractThe time course of the uptake of copper by excised barley roots (Hordeum distichumL.) after 24 h shows other characteristics than after 2 h. A further investigation of the concentration dependent uptake of copper by intact roots and kinetic analysis demonstrates a biphasic pattern for 2 h uptake periods, and possibly monophasic behaviour for uptake periods of 20 min and 24 h.Plasmolysis data of cortex cells of barley roots indicate that concentrations above 80 μM Cu are unphysiological with regard to longer uptake periods

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04415.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe effects of sucrose and abscisic acid (ABA) and their interaction on development and senescence of petals were studied with leafless roses cultivar Super Star. Sucrose and ABA had opposing effects on the cut flowers. Sucrose retarded and ABA promoted processes associated with senescence: wilting, increase in pH, “blueing” and decrease in protein content of petals. These opposing effects are mutually antagonized when both chemicals are applied. ABA applied to flowers cut at the bud stage, promoted the rate of petal growth (but not their final size), increased respiration and caused a decrease in sucrose and an increase in level of reducing sugars.It is suggested that one way by which ABA accelerates senescence of cut roses is by promoting petal growth and respiration, thus decreasing the carbohydrate level in the petals and triggering the chain of metabolic processes leading to ag

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04416.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractHoneydew and leaf extracts fromSalix babylonicaindicate that large quantities of cytokinin are present in the leaves and are transported through the phloem of this plant during late autumn. The active compound in the extracts could be hydrolysed with β‐glucosidase, whereafter it showed the same chromatographic behaviour as zeatin. It is proposed that cytokinins in the leaves are converted to the glucoside and then redistributed to the rest of the plant organs where it is stor

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04417.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractIt is shown that the response of transpiration to light is different in species from Gramineae and Cyperaceae compared to species from other families. Blue light (380–500 nm) causes both a rapid response (rise time 2 min) and a slow response (rise time 5 to 10 min) in species from these two families but induces only a slow response in other families. Red light results only in a slow response in all plants investigated.It is hypothesized that the rapid response to blue light is due to the special anatomy and/or function of the so‐called grass‐like (graminaceous) stomata of plants belonging to Gramineae or Cyper

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04418.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe kinetics of uptake of K+and Mg2+were studied by using intact soybean [Glycine max(L.) Merr. cv. Amsoy] roots. Uptake of K+in the concentration range 1.29 × 10−5to 1.82 × 10−3M can be represented by two phases of a single, multiphasic mechanism. Similarly, uptake of Mg2+in the concentration range 4.10 × 10−6to 2.49 × 10−4Mw

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04419.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractEthylene concentration in sunflower (Helianthus annuusL.) cuttings increased 5‐fold within 6 h after submersion in distilled water and then declined. When only the basal half of the cutting was steeped in water, ethylene concentration was slightly over half the concentration of the completely submerged cutting. Ethylene concentration also increased when cuttings were wrapped with moist paper tissue. When wrapped with Saran transparent plastic film, ethylene concentration increased continuously for 12 h. When part of the stem of an intact plant was wrapped with Saran, ethylene also increased in that part of the stem. When wrapping was removed or submersion was discontinued, accumulated ethylene in the cuttings decreased, much faster from unwrapped cuttings than from previously submerged ones. During 3 h submersion, ethylene production rate in submerged cuttings was approximately 10% of that for the controls and over 97% ethylene escaped out of the control cuttings while only 22‐52% escaped from the submerged cuttings.Water content increased during submersion and decreased when submersion was discontinued. Water content did not change significantly during wrapping, but decreased when the cuttings were unwrapped. High water content in the submerged cuttings was apparently not related to the high ethylene concentration in the cuttings.Causes of ethylene increase in flooded plants were discussed and it was concluded that one of the first and major causes is the accumulation of ethylene in flooded portions of the plants due to the blockade of ethylene escape by wa

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04420.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractExtracts from germinating soybean [Glycine max(L.) Merr.] cotyledons were assayed for aminoacyl‐tRNA formation. This esterification reaction depends on several factors, which must be determined and controlled for each system investigated. The reaction was maximum when the Mg: ATP ratio was 12.5 and concentrations were 9 and 0.72 mM, respectively. The optimum temperature for thein vitroreaction was 25°C. In addition, the reaction was inhibited by inorganic pyrophosphate and magnesium could be replaced by spermidi

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04421.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe hydrolysis of seven peptidase substrates by petal extracts of tulip (Tulipa sp.cv. Guillaume Tell) was assayed at four stages in the life cycle of the petals. During senescence pronounced increases from three‐ to sixfold took place in all the activities. At the same time the amount of soluble protein decreased about 75% and there was a simultaneous increase in free amino acids.The activity levels (on a dry weight basis) in the petals at the beginning of withering were rather similar to those present in normal leaves. Despite their different pH‐optima (5‐9), all the peptidases probably act in the mobilization of protein amino acids in the senescing p

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04422.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractIn the first leaf of wheat (Triticum aestivum L.cv. Capelle) the content of soluble protein diminished to about 50% of the initial value between the 7th and the 19th day after sowing.In order to understand proteolysis in the leaves, the activities of several peptidases were measured in extracts from leaves at four different ages. The carboxypeptidase activities increased during the growth of the leaves, and then began to decrease. The activities of the alkaline peptidases increased, while that of the benzoyl‐DL‐arginine‐p‐nitroanilide (BAPA) hydrolysing enzyme decreased during the whole period studied. The “naphthylamidase” activities showed first a slow rise, but then leveled off. Two bands with naphthylamidase activity could be detected after disc electrophoresis.All the peptidases studied were present in the leaves at rather high concentrations. This indicates that they all may participate in the hydrolysis of leaf proteins into free

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04423.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

AbstractThe activities of several carboxy‐ and aminopeptidases were assayed in extracts prepared from the cotyledons of resting and germinating peanut seeds as well as from growing and fully differentiated peanut leaves.Carboxypeptidases acting on two carbobenzoxydipeptides Z‐Phe‐Ala and Z‐Ala‐Phe at pH 5.2 showed minimal activities in “resting” cotyledons, and only slight increases occurred during 7‐day germination at 28°C. In peanut leaves the corresponding activities were quite high, about 20‐ and 6‐fold compared to “germinating” cotyledons.Peptidases acting on Leu‐Tyr at pH 8.6 and on Ala‐Gly at pH 7.8 were highly active in resting cotyledons, and the activities remained essentially constant during germination; corresponding activities in leaves were much smaller (about 15–25% of those in cotyledons).“Naphthylamidases” hydrolyzing the β‐naphthylamides of Phe, Leu, and Arg at pH 7.2, were also highly active in resting cotyledons; during germination the first activity stayed at a constant level while the other two decreased progressively. Leaves showed relatively high activities on Phe‐bT‐NA and Leu‐β‐NA but only minimal activity on Arg‐β‐NA.It is tentatively concluded that the peptidases acting on Leu‐Tyr and on Ala‐Gly as well as the naphthylamidases function in the mobilization of the reserve proteins of peanut cotyledons during germination. The carboxypeptidases, in con

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1976.tb04424.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY