摘要:

Abstract.Anthocyanin biosynthesis in red cabbage seedlings has been shown to be under a red/far‐red (R/FR) reversible phytochrome control. The ‘escape’ of anthocyanin synthesis from FR photoreversibility occurred between 12 and 20 h. However, a similarity exists between the escape curve and the temporal change in sensitivity to FR alone, which suggests that some of the ‘escape’ may be due to the promotive effect of FR. Some escape times may not therefore be a true measure of the duration of Pfr action, contrary to the traditi

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11587400

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Abstract.The influence of indol‐3yl‐acetic acid (IAA) and abscisic acid (ABA) on the capacities of the cytoplasm and vacuole and their effects on unidirectional sodium fluxes across the plasmalemma and the tonoplast of aged red beet storage tissue was investigated. After loading the tissue in a labelled NaCl solution the efflux of radio‐activity was measured in unlabelled NaCl. By means of compartmental analysis the capacities and fluxes were determined and compared with those obtained after loading and elution in the presence of IAA or ABA.It was established that both IAA and ABA affect sodium transport across the principal cell membranes. Both hormones inhibited the efflux across the plasma‐lemma, possibly by affecting a Na+for H+exchanging system. Efflux across the tonoplast was stimulated by IAA and influx across the same membrane was enhanced by ABA. It was suggested that IAA stimulated a proton pump at this level while the influence of ABA remained difficult to

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11587403

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Abstract.Seedlings ofBetula pendulawere grown in a controlled environment chamber at quantum flux densities of 50, 250 and 600 μmol m−2s−1. The relationship between the flux densities of absorbed CC2and quanta was determined for shoots of whole seedlings. Rates of both light‐saturated andin situ(measured under the growing conditions) net photosynthesis were determined and the pholosynthetic quantum yields under light‐limiting conditions were calculated. Anatomical leaf characteristics, chlorophyll contents and sizes and densities of the photosynthetic units (chlorophyll/P700) were determined. Chloroplasts were isolated and their rates of 2,6‐dichlorophenol indophenol photoreduction were measured together with their pool sizes of the electron transport carriers plastoquinone and cylochrome ƒ.Although acclimated to different quantum flux densities, the three birch populations showed the same quantum yield of net photosynthesis. This was approximately 0.028 in normal air (21.2 kPa oxygen) and about 0.040 when photorespiration was largely inhibited in 2.0 kPa oxygen. In addition, thein situnet photosynthesis rates were limited by the absorbed quantum flux density for low, intermediate and high light grown seedlings. It was concluded that birch acclimated to the three light regimes at different levels of organization (metabolic and anatomical). Thus, the quanta which were absorbedin situcould be transferred into chemical equivalents at an optimal and constant efficiency. The use of different reference bases for expressing rates of net photosynthesis are als

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11587416

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Abstract.Net photosynthesis, photosynthetic electron transport, and leaf area density of photosynthetic units have been studied in developing, mature, and old leaves of seedlings ofBetula pendula. The photosynthetic quantum yield under light‐limiting conditions and the leaf area related rale of light‐saturated net photosynthesis were lower in developing than in mature and old leaves. Developing leaves also had more oxygen inhibition of photosynthesis, a lower pool size of plastoquinone in the electron transport chain, a lower chlorophyll content and a lower leaf area density of photosynthetic units than mature and old leaves. The photosynthetic properties of The oldest leaves resulted partly from acclimation to shade and partly from a different ontogeny to that of younger lea

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11587561

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Abstract.Droopy mutant of potato (Solanum tubero‐sumL., groupPliureja) wilts because of excessive stomatal opening (Waggoner&Simmonds, 1966). Progeny of the cross between potato clones C.P.C. 4461 and C.P.C. 4463 showed characteristics similar to those of the original droopy potato. These plants wilted at high vapour pressure deficit and their stomatal conductances in the light and the dark were higher than those of normal plants. Conductances were reduced by applied abscisic acid (ABA), but stomata remained partially open even when guard cells were plasmolysed. Leaves of droopy plants accumulated very little ABA when water‐stres

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11587567

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Abstract.Aging of chloroplasts bothin vivoandin vitrocauses a considerable loss in the 2,6‐dichlorophenol indophenol (DCPIP)‐Hill reaction with water as electron donor. The loss can be reduced by exogenous electron donors like diphenyl carbazide (DPC). suggestive of aging‐induced damage of the oxygen evolving system. Aging also brings about a considerable loss in methylviologen (MV) reduction mediated by Photosystem I (PS I) of chloroplasts with an ascorbate‐DCPIP couple as the electron donating system.The loss in the electron transport ability of the plastids is faster duringin vitrocompared toin vivoaging of the chloroplasts.Light protects the photo‐electron transport ability of chloroplasts during aging of intact leaves in contrast to its action during aging of the isolated o

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11587573

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Abstract.In white light(W) stem elongation of green plants is stimulated when some far‐red light (F) is added to W (Holmes&Smith, 1975, 1977b). The effect of adding F to a background W was quantified usingVigna sinensisL. plants and relatively high fluence rate W. F was given selectively to the 1st internode and the internode elongation rate (E.R) was recorded using linear voltage displacement transducers. Results confirm that adding F to background W stimulates internode E. R. The stimulation is very quickly measurable after switching F on and falls off rapidly after switching F off. The stimulation is not dependent on F fluence rate perper sebut is strictly dependent on the quantum flux ratio F/W. These data are strongly in favour of phytochrome as the receptor, whose activity is controlled by the PFRcontent or the [PFR]/[P]ratio. A common mode of action for phytochrome in W and in darkness is suggested. The results indicate independence and additivity of the E. R.modulation by W light quantity and of the modulation by light qualit

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11587578

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Abstract.Endosperm tissue from developing grains of a line of wheat (Triticum dicoccoides) which accumulates up to 30% protein in the mature grain, was examined by electron microscopy to establish the ontogeny of the storage protein bodies. Ultrastructural evidence suggests that storage proteins of wheat may be transported from their site of synthesis on the rough endoplasmic reticulum (ER) to protein bodies by two different routes within the endomembrane system. The first route, which probably functions throughout protein deposition, involves the transport of protein from the cisternal rough ER to the protein vacuolesviathe Golgi apparatus. The second route, observed 20 d after anthesis, appears to lead directly from dilated regions of the rough ER to protein vacuoles, bypassing the dictyosomes. Phytin inclusions are found in protein vacuoles of starchy endosperm cells adjacent to the aleurone layer of developing grain.

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11587585

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Abstract.A comparison is made of the relative effectiveness of light quality and light quantity on the elongation growth ofSinapis albahypocotyls. The results show that hypocotyl extension rate in plants which have not previously been exposed to light is controlled primarily by the prevailing photon fluence rate when the phytochrome photostationary state lies between ∼0.033 and ∼0.81. Below ∼0.033, changes in photostationary state also have a marked effect on extension rate. Elongation growth in light‐adapted plants is controlled by both photon fluence rate and the spectral quality of the incident radiation at all photoequilibria. Photosynthesis can modify these responses but is not essential as a prior condition for a green plant to respond to changes in light quality and q

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11587590

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Abstract.When artichoke tuber tissue was cultured in mineral salts, the induction of DNA synthesis and subsequent cell division was dependent upon the presence of auxin in the incubation medium. Evidence is provided that an obligatory set of metabolic events precedes auxin‐induced DNA synthesis, and previous work has associated these with protein synthesis. As a consequence the auxin‐induced changes in nuclear and cytoplasmic proteins have been investigated. Using 2D gel electrophoresis, qualitative alterations in nuclear non‐histone proteins have been detected from the earliest treatment times with auxin. These changes were progressive, starting with four novel proteins after 3 h auxin treatment and ending with about forty when DNA synthesis commences some 18–21 h later. Qualitative alterations in phosphorylated nuclear proteins due to auxin treatment were only detectable when DNA synthesis commenced. In contrast, few qualitative alterations in cytoplasmic proteins were detectable, with the major change being in phosphorylated proteins at the onset of DNA synthesis.A possible model of auxin action is outlined which involves sequential and progressive changes in the synthesis of nuclear proteins and the control of gene expression eventually leading to DNA sy

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11587596

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY