摘要:

Light‐induced absorbance changes were investigated in vivo in the fungusVerticillium agaricinum(Link) Corda. There was a broad light‐induced absorbance decrease in the blue and near UV with a maximum at 384 nm. An action spectrum indicated that the absorbance changes were due to photo‐bleaching of a pigment with an absorption spectrum that was similar to the action spectrum. Neither redox reactions nor energy metabolism were involved in the photo‐bleaching process. A direct comparison of action spectra for light‐induced absorbance changes and photo‐induction of carotenogenesis suggests that the photo‐bleaching may not be related to photo‐induction of

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb02266.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The effect of photoperiod and temperature on growth and induction and development of frost hardiness in cloudberry (Rubus chamaemorusL.) was examined in two experiments. The photoperiods were 8, 12 or 24 h and the temperatures were 18, 15, 12, 9, 4, 3, –3 or –4°C depending on the experiment. The level of hardiness was expressed as LT66or LT50(the lethal temperature for 66 or 50% of the plant material) for percentage of bud break and for the degree of coloring by triphenyltetrazolium chloride for rhizomes. The vegetative growth was clearly affected by daylength; petiole elongation, leaf growth, shoot dry weight and number of shoots per plant were all reduced under short days compared with long days. However, the photoperiod had no significant effect on hardening of buds or rhizomes. Hardening increased with successively decreasing temperatures. To get the maximum hardiness, plants had to be exposed to freezing temperat

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb02267.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Developing cotyledons ofPhaseolus vulgarisL. were labeled for 30 min with [3H] amino acids, homogenized, and the proteins fractionated on sodium dodecylsulfate (SDS) polyacrylamide gels. Fluorographs of these gels showed that the polypeptides of phaseolin, the major reserve protein ofP. vulgaris, were synthesized as precursors which could be distinguished from the polypeptides of mature phaseolin by their slightly lower mobility.When extracts of cotyledons labeled for 45 min with [3H] amino acids were fractionated on isopynic sucrose gradients, radioactive phaseolin banded at the same density (1.14 g cm‐3) as the endoplasmic reticulum (ER)‐marker enzyme NADH‐cytochromecreductase. Fractionation in the presence of 3 mMMgCl2indicated that the newly‐synthesized phaseolin was associated with the rough ER. Pulse‐chase experiments showed that phaseolin was transiently associated with the ER, and later accumulated in the protein bodies.Treatment of isolated ER with proteinase K showed that phaseolin polypeptides were degraded only if Triton X‐100 was present, indicating that phaseolin was membrane‐protected, probably enclosed within the vesicles. ER‐associated phaseolin associated to an 18S form at pH 4.5 in the presence of 0.3MNaCl and 100 mMsodium acetate. The polypeptides of ER‐associated phaseolin had a slightly lower mobility on SDS‐gels than polypeptides of protein body phaseolin. ER‐associated phaseolin had a carbohydrate content of 6.8%, while protein body‐derived phaseolin had a carbohydrate content of 6.2%. When cotyledons were labeled simultaneously with [14C] amino acids and [3H] glucosamine or with [14C] amino acids and [3H] mannose, the [3H]/[14C] ratio of ER‐derived phaseolin was similar to that of protein body derived phaseolin, indicating that the faster mobility on SDS‐gels was not due to the detachment of carbohydrate. Experiments in which the carbohydrate side chains were removed with endoglycosidase H, and the resulting polypeptides subjected to electrophoresis in SDS‐gels showed that the differential mobility of the glycopolypeptides of phaseolin reside

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb02268.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Cyclic adenosine 3′:5′‐monophosphate (cAMP) was extracted fromPhaseolus vulgarisL. cv. Limburg seedlings andChlorellasp. The cAMP was purified by charcoal adsorption, polyvinylpyrrolidone (PVP) and Dowex 50 W × 8 column chromatography and by preparative high‐performance liquid chromatography (HPLC). Quantitation was achieved by combining phosphodiesterase (PDE) treatment with analytical HPLC (reversed phase ion‐pair partition chromatography) and cAMP‐dependent protein kinase activation. This provided a very specific, accurate and sensitive assay for cAMP determinations. The cAMP content found inChlorella(70–90 pmol/g dry wt) was comparable with previous reports using other quantitation methods, whereas the endogenous concentration found in bean seedlings (92 pmol/g dry wt) was considerably lower than previously

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb02269.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

By addition of chloramphenicol (CAP) to the growth medium of green soybean (Glycine maxL.) cells in batch culture, growth is inhibited and the activity of the cytochrome oxidase decreases to 60% of the value found in control cells. The presence of CAP induces an enhancement of the contribution of the alternative pathway to total respiration. This enlarged contribution results both from a higher capacity of the alternative pathway and from a greater part of this capacity being used. Also in mitochondria isolated from cells treated with CAP, a higher capacity of the alternative pathway has been found, while the part of this capacity which is really used is comparable with the values found in control cells.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb02270.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The speciesUrtica dioicaL.,Plantago majorssp.majorL.,Plantago lanceolataL.,Hypochaeris radicataL. ssp.radicataandHypochaeris radicatassp.ericetorumVan Soest were grown under high and low nutrient conditions (1/4 Hoagland and 2% of 1/4 Hoagland further called the 100% and 2% treatment, containing 3.75 mMNO‐3and 0.075 mMNO‐3, respectively). After a certain period half of the plants were transferred from low to high or high to low nutrients, yielding the 100%/2% and the 2%/100% treatments. The kinetics of nitrate uptake in the range of system I of the five species grown under the different nutrient conditions were measured during a three week experimental period. The nitrate uptake of all the species showed the characteristic features of Michaelis‐Menten kinetics. Under low nutrient conditions the apparent VmaxofU. dioicaexpressed per g dry root was lower than under high nutrient conditions. ForH. radicatassp.radicataand forH. radicatassp.ericetorumthe reverse was found. The Vmaxvalues ofP. majorssp.majorwere almost the same for the two treatments. The apparent Vmaxin young plants ofP. lanceolatawas higher in the 100% treatment than in 2%; whereas the reverse was found in mature plants. The results are explained in relation to the relative growth rate, the shoot to root ratio and the natural environment of the species. The apparent Kmvalues were not influenced by the different treatments. Differences in Kmbetween the species, if any, were very small. It is suggested that the Vmaxis a more important parameter for the distribution of plant species in the field than the Km. The rate of nitrogen accumulation was calculated from growth data and the contents of nitrate and reduced nitrogen. It is concluded that the Vmaxof system I for nitrate uptake in most cases was sufficient to explain the observed growth

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb02271.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

The ultrastructural effect of carotenoid deficiency in wheat (Triticum aestivum L.) was studied after adding the herbicide SAN‐9789 to the growth medium. The presence of SAN‐9789 (28 mg I‐1) resulted in an almost complete absence of carotenoids. For plants grown in darkness the lack of carotenoids was accompanied by a reduction in partitions between primary thylakoids as well as a change in appearance of the plastoglobuli from small and black (osmiophilic) to large and greyish white (less osmiophilic). When plants were grown in weak red light (16 mW m‐2), the presence of SAN‐9789 also resulted in an almost complete absence of grana, a decrease in the ratio of chlorophyllb/chlorophyllafrom 0.25 to 0.1, and an almost complete absence of prolamellar bodies. The greatest differences in carotenoid content, in amount of grana, in chlorophyllb/chlorophyllaratio, and in number of prolamellar bodies, all occurred between 0.28 and 2.8 mg I‐1of SAN‐9789. The change in appearance of plastoglobuli occurred at a lower SAN‐9789 concentration, between 0.028 and 0.28 mg I‐1. The ultrastructural responses to the SAN‐9789 treatment could be related to the effect on the carotenoid synthesis in different ways. The disappearance of thylakoid partitions was connected to a structural role of carotenoids, while the disappearance of the prolamellar bodies was dependent on the photoprotective role of carotenoids. The change in shape and size of plastoglobuli was not correlated to the presence of carotenoids. However, a connection to the accumulation of the carotenoid precursor

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb02272.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

It has been suggested previously that Japanese larch (Larix kaempferi) exhibits characteristics of C4photosynthesis. To further evaluate this suggestion, stable carbon isotope ratios were determined for leaf and bark tissue ofLarix gmelini, L. kaempferi, L. laricina, L. Iyallii, L. occidentalis, andL. sibirica.All δ13C values were more negative than –22‰. Short‐term labeling with14CO2showed that phosphoglyceric acid and other phosphorylated compounds were the first products of photosynthesis inL. sibirica.Both of these results strongly suggest that the initial fixation of atmospheric CO2in these sixLarixspecies is accomplished solely via the C3photosynthetic p

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb02273.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

A molecular mechanism is proposed for unitary multiphasic uptake in which the carrier has two binding sites for the substrate. The first site binds n‐1 molecules of substrate, and then one additional substrate molecule can become bound at the second binding site. Only this last molecule is transported in the operation of the carrier molecule. In the free state, the carrier can be activated to successive states with increasing affinities for the substrate in the two binding sites. The mechanism is resolved for the steady state conditions, obtaining a simple uptake rate equation, which fits the experimental data. Methods for determining the parameters of the equation are presented. Evidence other than kinetics is discussed for the mechanism. The mechanism also provides a physiological interpretation for multiphasic uptake: the active transport mechanisms (energy‐requiring mechanisms) are prevented from operating at high substrate concentrations, thus preventing a waste of energy by the ce

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb02274.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

Four varieties of maize differing in drought resistance and geographical origin (Swabi White and Shaheen from Pakistan, Garbo and Goldprinz from Germany) were analyzed for their proline and abscisic acid (ABA) accumulation during a prolonged water stress period. Proline levels increased continuously during the stress period in all the four varieties, but to different amounts. The drought‐susceptible varieties Shaheen and Goldprinz produced higher levels of proline than the drought‐resistant varieties Swabi White and Garbo. A negative correlation was also found between maximal ABA contents and degree of drought resistance during prolonged stress of younger plants. ABA levels did not increase steadily, but reached a maximum long before the end of the stress phase, and then declined. The results are discussed in relation to the possibility of using proline and ABA levels as biochemical indicators of resistance against drou

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1982.tb02275.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY