摘要:

AbstractPhycochromes b and d, two types of photoreversibly photochromic pigments previously extracted from the blue‐green algaTolypothrix distorta, which contains phycoerythrocyanin, have now been found in threeAnabaenastrains also containing phycoerythrocyanin. Tests for the presence of phycochromes b and d in a number of blue‐green algae lacking phycoerythrocyanin have been negative. The possibility that phycochrome b‐type absorbance changes are due to changes in the α‐subunit of phycoerythrocyanin is d

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb03290.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractCoumarin induced root formation and stimulated fresh weight production in hypocotyl explants ofGlycine maxL. culturedin vitro. All stimulatory effects caused by coumarin were induced within a relatively narrow range of concentrations between 1–500 μM, yielding optimum dose response curves. When coumarin was combined with kinetin fresh weight increased considerably, at optimum concentrations to a level almost as high as that obtained with NAA (10 μM) and kinetin (10 μM). Root formation was almost completely inhibited when kinetin was added in combination with coumarin. NAA + coumarin had small stimulatory effects on fresh weight. but were inhibitory in root formation. The frequency of rooting per explant, texture and pigmentation were also affected by different treatm

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb03291.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractThe effects ofcis. transabscisic acid on response to chilling was investigated in callusedNicotiana tabacumL. pith explants. Explants pretreated with 10‐4MABA underwent approximately 50% less cellular leakage when chilled at 2°C under short‐day conditions for 10 d than the comparable non‐treated tissue. Growth in terms of fresh and dry weights, although poor in comparison to non‐chilled (20°C, long days) treatments, was more than twice that of the non‐ABA‐treated material. On an absolute dry weight basis proline content increased on chilling from 0.7 to 3.4 mg g‐1in non‐ABA‐treated explants, but rose to nearly 17 mg g‐1in the tissue treated with ABA. Only in the case of cold‐hardened. ABA‐treated tissue could some cells survive subzero temperatures and regenerate callus again. It is suggested that at least part of the ameliorating effects of ABA result from an increas

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb03292.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractLeaves of twelve C3species and six C4species were examined to understand better the relationship between mesophyll cell properties and the generally high photosynthetic rates of these plants. The CO2diffusion conductance expressed per unit mesophyll cell surface area (gCO2cell) cell was determined using measurements of the net rate of CO2uptake, water vapor conductance, and the ratio of mesophyll cell surface area to leaf surface area (Ames/A). Ames/A averaged 31 for the C3species and 16 for the C4species. For the C3species gCO2cellranged from 0.12 to 0.32 mm s‐1, and for the C4species it ranged from 0.55 to 1.5 mm s‐1, exceeding a previously predicted maximum of 0.5 mm s‐1. Although the C3speciesCammissonia claviformisdid not have the highest gCO2cell, the combination of the highest Amesand highest stomatal conductance resulted in this species having the greatest maximum rate of CO2uptake in low oxygen, 93 μmol m‐2s‐1(147 mg dm‐2h‐1). The high gCO2cellof the C4speciesAmaranthus retroflexus(1.5 mm s‐1) was in part attributable to its thin cell wa

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb03293.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Abstract4‐Chloroindole‐3‐acetic acid methyl ester was identified unequivocally inLathyrus latifoliusL.,Vicia fabaL. andPisum sativumL. by thin layer chromatography, gas chromatography and mass spectrometry. The gas chromatographic system was able to separate underivatized chloroindole‐3‐acetic acid methyl ester isomers.The quantitative determination of 4‐chloroindole‐3‐acetic acid methyl ester in immature seeds of these three species was performed by gas chromatography – mass spectrometry using deuterium labelled 4‐chloro‐indole‐3‐acetic acid methyl ester as an internal standard.P. sativumcontained approximately 25 mg kg‐1,V. faba1–2 mg kg‐1andL

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb03294.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractExtracellular invertase ofRhizobium japonicumand its role in free sugar metabolism in the developing root nodules ofSesbania grandifloraL. was studied. The enzyme hydrolysed sucrose extracellularly, and its release was substrate inducible. 0.1Mβ‐mercaptoethanol released the cell‐bound form of this enzyme. The production of invertase was low when glucose, galactose, mannose, fructose and raffinose were used as carbon sources in the growth medium. In the developing nodules sucrose was the major sugar. The content of fructose was low in comparison with that of glucose – suggesting that in the nodules, fructose is converted to glucose prior to its entry into the bacterial cell. The content of glucose synchronised with the pattern of change in the activity of invertase in the n

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb03295.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractEthylene losses from the gas phase of various container‐seal systems were studied to develop acceptable methods for containing ethylene during experiments. Ethylene at an initial amount of 104 μI I‐1was stored in glass vials at near atmospheric pressure for 20 h at 25–27°C and at 35% relative humidity external to the vials. Crimped serum vials sealed with saturated (NH4)2SO4solution, neoprene rubber septa, nitrile rubber (Hycar) septa, butyl rubber septa, and brown translucent silicone rubber septa lost ethylene at the rate of 1.8, 10.2, 16.2, 16.5, and 40.2 nl m‐2s‐1, respectively, over the 20‐h period. Screw‐capped reaction vials sealed with white silicone rubber septa lost ethylene at the rate of 30.2 nl m‐2s‐1. The (NH4)2SO4solution was utilized as a seal by inverting a vial so that the salt solution covered the internal surface of the vial septum. Saturated (NH4)2SO4solution is an effective seal. Silicone rubber should be avoided as a seal in systems for containing ethylene. Ethylene production values in the literature may be underestimates where silicone rubber s

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb03296.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractHourly development during a normal day of photosynthesis, transpiration, leaf and root respiration, and of N.P.K nutrition in Zea mays.Metabolism ofZea maysL. cv. INRA F7×F2can be measured hourly with the “C23A system”, under favourable and constant growth conditions. The photosynthesis is especially stable and is submitted only to a development linked with the leaf surface growth. During the vegetative stage the leaf surface increases regularly both in the day and in the night. The water loss does not change during the diurnal period and remains important during the night if humidity is less than 100%. The leaf respiration is nearly stable. The root respiration, measured with O2and CO2, fluctuates according to a typical rhythm with two maxima. Day and night mean rates were about the same. The respiratory quotient is about one during the vegetative stage. There is no decrease in the rate of phosphate absorption during the night, and a very small decrease in the rate of nitrate absorption. Ammonium is totally consumed in the first hours after renewal of the nutrient solution. At the same time the potassium consumption is decreased, and then presents a maximum followed by a night reduction. Under our conditions, all of the observations allowed us to assume the presence of an adequate reserve of assimilates and suggest the existence of a precise regulation process, which can ensure an even day night functioning of the plant metabolism, but which does not preclude the presence of internal rhythms, as indicated by the oscillation of the root respira

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb03297.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractWe examined ethylene effects on root regeneration in tomato leaf discs culturedin vitro. Applied ethylene or Ethephon did not stimulate rooting in the leaf discs. In the presence of indoleacetic acid. 5 × 10‐6M, these substances significantly inhibited root formation. Ethylene production (nl C2H4· (24 h)‐1.flask‐1) was positively correlated with increased IAA concentrations at various times during the culture period and, as a consequence, with the rooting response after 168 h. However, separate testing of equimolar concentrations of seven different auxins and auxin‐like compounds showed no positive correlation between the rate of ethylene production and subsequent rooting response. Aeration of gas‐tight flasks containing leaf discs and absorption of ethylene evolved from the discs by mercuric perchlorate in gas‐tight flasks or pre‐treatment of leaf discs with AgNO3significantly enhanced IAA induced root regeneration. Thus, these studies indicate that ethylene is not a rooting hormoneper se. Furthermore, ethylene (whether applied externally or synthesized by the tissue) does not appear to account for the ability of auxin to st

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb03298.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

AbstractNet photosynthesis of seedlings ofPinus silvestrishas been measured and compared with the activities of photosynthetic electron transport and extracted RuBP carboxylase. The effects of prolonged frost hardening (photoperiod 8 h, + 3°C) followed by winter stress at subzero temperatures were analysed. There was a parallel effect of frost hardening and winter stress on the photosynthetic properties of both intact seedlings and isolated chloroplast thylakoids. The activity of extracted RuBP carboxylase was less affected by the treatments. In relation to earlier works we conclude that the decay of net photosynthesis in winter climate is determined by the electron transport properties of the chloroplast thylakoids,i.e.by the pool sizes of photosynthetically active plastoquinone.The results of this work justify the definition of two phases in the response of conifers towards autumn and winter climates: I. Frost hardening occurs at temperatures slightly above zero and it does not affect the efficiency of photosynthesis as defined by the quantum yield at rate limiting light absorption. II. Winter stress occurs at subzero temperatures and it is characterized by a suppression of the photosynthetic efficiency as a result of damage within the photosynthetic apparatus

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1980.tb03299.x

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY