摘要:

AbstractCallus ofArabidopsis thaliana(L.) Heynh. was examined for the kinetics of sulfanilamide inhibition of growth. Two geographic races of this species were compared for relative sulfanilamide sensitivity (as assessed by dry weight increase on drug‐containing medium) and rate of drug uptake.It was found that low concentrations of sulfanilamide in the culture medium (∼ 100 μM) inhibited callus growth and that low concentrations ofp‐aminobenzoate (20 μM) competitively antagonized the sulfanilamide effect.Racial variation for sulfanilamide sensitivity was demonstrated. A partially drug‐resistant race had greater sulfanilamide uptake (per gram fresh weight) than a sensitive race. suggesting that relative drug‐sensitivity was not determined by the capacity to exclude su

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb01588.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe differences in K+uptake of different segments of excised roots of two thermophilic plants (rice,Oryza sativaL. cv. Dunghan Shali and cucumber,Cucumis sativusL. cv. Csemege Fürtös) and a non‐thermophilic plant (wheat,Triticum aestivumL. cv. Aurora) were investigated in the presence and absence of Ca2+, at 0 and 25°C, using radiotracer K+(86Rb+) technique. The K+uptake exhibited different temperature‐ and Ca2+‐dependent distributions along the root axis for the different species studied. In the case of rice and cucumber an extraordinarily large K+uptake occurred in the apical root portion at 0°C if Ca2+was omitted. The presence of Ca2+diminished this anomaly. For wheat normal K+uptake patterns were observed under similar conditions. At 25°C Ca2+‐stimulated K+uptake may appear in each root segment, depending upon species and composition of the uptake solution. The results indicate that there may be considerable differences in the compositions of the cell walls and membranes of root cells of thermophilic and non‐thermophilic plants, and in their ion‐exchange properties, especially in t

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb01589.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractThe effects of Ca2+and temperature on the K+contents of root segments of wheat (Triticum aestivumL. cv. Aurora), rice (Oryza sativaL. cv. Dunghan Shali) and cucumber (Cucumis sativusL. cv. Csemege Fürtös) were investigated with special regard to the low‐temperature anomaly of the K+uptake of thermophilic plants. The anomaly occurred in those root segments where the K+contents turned out to be highest. The K+contents of the apical root sections of thermophilic species responded in general to Ca2+in more pronounced ways than those of wheat, at both 0 and 25°C. The concerted actions of a purely physical process with negative temperature coefficient and of the special thermotropic properties of the membranes are suggested to be responsible for the low‐temperature anomaly. A strict discrimination between the Viets‐effect on the content (classical Viets‐effect) and on the uptake is proposed. The classical Viets‐effect seems to be related to alterations in both active transport and exchan

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb01590.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractInteraction of photoperiodism and zeatin, sucrose and water effects on the flowering of Chenopodium polyspermumRoot removal inChenopodium polyspermum, a quatitative short‐day plant, enhances flowering under non‐inductive conditions. Presence of roots may be mimicked by zeatin applications on buds. Induction of flowering by short days may be counteracted by applications of zeatin, and appearance of flowers depends on the balance between number of inductive short days and zeatin quantity applied. Sucrose added in the culture medium or applied on buds acts as zeatin. Applications of water on buds may also delay flowering. These results show the plurifactorial regulation of the floral development of this plant. The relations between the non‐specificity of the induction and the specificity of the morphogenetic response are disc

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb01591.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractA study of nitrate and chlorate uptake byArabidopsis thalianawas made with a wildtype and two mutant types, both mutants having been selected by resistance to high chlorate concentrations. All plants were grown on a nutrient solution with nitrate and/or ammonium as the nitrogen source. Uptake was determined from depletion in the ambient solution. Nitrate and chlorate were able to induce their own uptake mechanisms. Plants grown on ammonium nitrate showed a higher subsequent uptake rate of nitrate and chlorate than plants grown on ammonium alone.Mutant B25, which has no nitrate reductase activity, showed higher rates of nitrate and chlorate uptake than the wildtype, when both types were grown on ammonium nitrate. Therefore, the uptake of nitrate is not dependent on the presence of nitrate reductase. Nitrate has a stimulating effect on nitrate and chlorate uptake, whereas some product of nitrate and ammonium assimilation inhibits uptake of both ions by negative feedback. Mutant B 1, which was supposed to have a low chlorate uptake rate, also has disturbed uptake characteristics for nitrate.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb01592.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractNeedles of 20‐year‐old Scots pine trees (Pinus silvestrisL.) were permitted to photoassimilate14CO2for 1 h on different dates during the growing season. The loss of radioactivity from current, 1‐year‐old, and 2‐year‐old needles was followed, and the translocation of photoassimilated14CO2from older needle age‐classes to the elongating new needles studied. The effects of good mineral and water supply on translocation were also considered.In the spring, 1‐year‐old and 2‐year‐old needles accumulated14C. These reserves, together with current photosynthate, were utilized when the trees started growing. The 1‐year‐old needles exported14C to the current needles during the first weeks of elongation of the later, while no such translocation occurred from the 2‐year‐old needles. Removal of the 1‐year‐old needles resulted in translocation of assimilates from the 2‐year‐old needles to the current needles. The general pattern of translocation observed in the control trees was not changed when the trees were fertilized and irrigated.The new needles started to export assimilates in the middle of July when the photosynthetic rate per needle was comparable with that of the older age‐classes. This occurred about 4 weeks after positive net photosynthesis was first measured for the current shoot. The current needles of trees with good nutrient and water supply seemed to become self‐sufficient in photoassimilates earlier than

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb01593.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractCytokinin (CK), when applied to intact pea plants, considerably lowered endogenous lipoxygenase levels. Furthermore it was demonstrated that the triggering of senescence induced by leaf detachment was invariably accompanied by a significant increase of lipoxygenase activity and the CK application considerably decelerates lipoxygenase increment. It is suggested that the lipoxygenase repression induced by CK is a contributing mechanism to the overall antisenescence action of the hormone, and that this may have biological implications.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb01594.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractTungro virus infection decreased the chlorophyll content in the susceptible rice (Oryza sativa) cultivar ‘Taichung Native 1’, while it increased the pigment in the less‐susceptible cultivar ‘IR 20’ during the later stages of infection. The virus was recovered from the infected susceptibile cultivar as early as 3 days after inoculation. Relatively low amounts of virus were recovered from the less‐susceptible cultivar between 12 and 30 days after inoculation. The senescence of detached leaves of virus‐infected less‐susceptible cultivar incubated in water in darkness was considerably delayed compared to healthy leaves. The cytokinin activity in the extracts from inoculated less‐susceptible cultivar was 69% higher than in the extracts from t

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb01595.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractBenzyladenine (BA) was applied to intact bean (Phaseolus vulgaris) leaves at different stages of their growth. Changes in the amounts of cellular constituents resulting from the different treatments were followed and compared. RNA, protein, and chlorophyll contents, dry weight, fresh weight, and leaf area per single leaf continued increasing when leaves were treated with BA from an early stage, whereas in untreated leaves all these values levelled off or declined with advancing age. Besides these changes, BA treatment induced an increase in the DNA content. Changes in RNA content was more remarkable in response to application or deprival of BA treatment than the corresponding ones in protein and chlorophyll contents. The pattern of response to BA varied greatly according to the age at which the leaf received the treatment. As leaves aged, they lost the ability to increase their area and fresh weight in response to BA. However, continuous treatment with BA from an early stage kept the leaves young and able to respond.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb01596.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

AbstractA technique for C2H2‐reduction assay on intact plants ofAlnus incana(L.) Moench was evaluated. Cloned plants were grown, in pots, on fine gravel. During assay only the pot was inserted into a Perspex incubation chamber of simple construction. The incubation volume was rather small, plants with various shoot heights could be used, and the shoot was not exposed to the C2H4produced. Intact plants showed high and constant C2H2‐reduction rates during several hours of incubation. In comparison, excised nodulated roots conventionally incubated in test tubes showed low and decreasing rates, due to removal of the photo‐synthesizing shoot and injury to the root nodules when drawn from the pot. Repeated nitrogenase activity assays on the same intact individual plants did not affect growth. The technique thus proved useful in studies. where repeated nitrogenase activity measurements are impo

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1978.tb01597.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY