摘要:

Books reviewed in this article:PHOTOSYNTHESIS BIBLIOGRAPHY, (1976) Volume 7. Edited by Z. SESTAK&J. CATSKYPHOTOSYNTHESIS AND PLANT DEVELOPMENT. Edited by R. MARCELLE, H. CLUSTERS&M. VAN POUCKEWORLD SOYBEAN RESEARCH CONFERENCE. II: PROCEEDINGS. Granada Publishing, St Albans, (Sept. 1980)and ABSTRACTSGranada Publishing, St Albans, (Sept. 1980) edited by FREDERICKT. CORBIN

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1981.tb01055.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11604541

出版商:Blackwell Publishing    

年代:1981

数据来源: WILEY

摘要:

Abstract.In many plant physiological studies, quantitative determination of ethylene in aqueous solutions is necessary. We describe two methods for such measurements based on vacuum extraction, or on stripping ethylene from solution with the carrier gas of a gas chromatograph. The gas‐stripping technique is limited by the small sample volumes that can be used, whereas the vacuum extraction technique can accommodate much larger volumes and is useful when the ethylene concentration in the solution is very low. The use of these techniques will facilitate the treatment of submerged plant tissues with known amounts of ethylene, and also the quantitative determination of ethylene from tissues grown in either static or continuous flow liquid culture

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11604542

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.A conceptual framework is presented for modelling short‐term processes in the plant and its environment as an integrated system. Flows of water, water vapour, heat, momentum, CO2, soluble carbohydrate and phosphorus are all described by equations of the same general type, i.e. in terms of diffusivity‐type parameters, capacities and potential gradients. A representative volume of the crop is divided horizontally into layers and vertically between crop and environment for treatment by a finite‐difference method. Vertical flow occurs in the atmosphere, soil, stems and larger roots, andilateral flow between leaves and air, and between finer roots and soil. The interception of direct sunlight and the flux densities of downward and upward diffuse radiation within layers are calculated by a step‐wise procedure.The conversions of materials within the plant are treated as functions of appropriate state variables. Schemes for carbon and phosphorus provide for flow to and from the translocation system, and for photosynthesis, respiration and growth.A model of a fully‐established lucerne crop is described and the sensitivity of model performance to changes in a number of parameter values explored. Simulation runs under varying conditions indicate realistic prediction of diurn

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11604544

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.Cells of the blue‐green algaCoccochloris peniocystis, grown at air levels of CO2, were exposed to [l4C]bicarbonate in the light for periods of 0.5 to 2.0 s followed by exposure to unlabelled bicarbonate for longer periods of time in the light. The kinetics of tracer movement during these pulse‐chase experiments demonstrate that the principal mechanism of CO2fixation in this alga is the C3‐pathway although an appreciable amount of the C4acid aspartate is found as one of the initial products of photosynthesis. Degradation of the labelled aspartate revealed that after 20 s of illumination, over 95% of the radioactivity was located in the β‐carboxyl of this C4acid. This alga possesses little, if any, capacity for either the enzymatic decarboxylation of C4acids or the regeneration of phosphoenolpyruvate (PEP) from pyruvate mediated by the enzyme pyruvate, Pidikinase. These data further demonstrate the lack of a functional C4‐pathway in

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11604546

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.Phosphate inhibited endogenous as well as 1‐aminocyclopropane‐1‐carboxylic acid (ACC)‐stimulated ethylene synthesis in slices of tomato fruit, segments of carrot root and pea hypocotyls. ACC concentrations of up to 10 mol m−3did not overcome this inhibition. Phosphate inhibited the conversion of14C ACC to ethylene in tomato fruit and vegetative tissue. Enzymatic conversion of ACC to ethylene by pea seedling homogenate was also inhibited by phosphate with a linear concentration dependency. The formation of ACC from S‐adenosylmethionine (SAM) by extracts of pink tomatd fruit was slightly, but not significantly, affected by phosphate. However, the SAM to ACC conversion was greater when extracts from tomato fruit were made in phosphate rather than in HEPES‐KOH buffer. Non‐enzymatic ethylene synthesis from ACC in a model system was stimulated by phosphate. We suggest that phosphate is an inhibitor of ethylene biosynthesis in higher plants and that one site of its control is the conversion of

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11604547

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.The rates of uptake of32P‐labelled orthophosphate by whole root systems of young apple trees (M.9 rootslocks and Worcester Pearmain seedlings) were measured in solution culture. Using a solution depletion technique, the32P‐phosphate uptake rates per unit length, surface area or fresh weight of roots were determined as a function of32P‐phosphate concentration in solution at the root surface over the range 0.25–10 mmol m−3. The effect of P concentration within various plant parts on the relation between uptake rate and external P concentration was studied using plants differing in internal P levels.The apparent minimutn P concentration below which P uptake ceased was of the order of 0.25–0.50 mmol m−3. Fluxes, inflows and unit absorption rates increased approximately proportionately with solution concentration up to 10mmolm−3. Except perhaps in the case of the low‐P M.9 plant, there was no evidence of a diminishing returns type of relationship over the range of solution concentrations examined. The threshold P concentration in solution above which uptake rates cease to increase thus appears to be higher for apples than for other species.At any given P concentration, fluxes, inflows and unit absorption rates were higher for M.9 than for Worcester and for low‐P plants than for high‐P plants. The difference between plants of different P status was more marked for M.9 and seems to be more closely related to shoot P

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11604549

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.The allocation of carbon in a vegetative barley plant is described as an open, three‐compartment model; the three compartments are soluble (which exchanges material with the environment), storage, and structure (both of which exchange material with the soluble compartment). The model shows a good fit with data on14C kinetics following14CO2feeding and some of its assumptions, properties and implications are discusse

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11604551

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.The tempo of rehydration of sunflower (Helianthus animusL.) leaves was measured after dehydration in a pressure bomb down to water potentials of −0.5 to −1.6 MPa. When rehydrated from small water deficits (−0.5 to −0.8 MPa) the plot of log rehydration rate versus time is concave. When rehydration starts from large deficits (−1.2 to −1.6 MPa) the semilog plot has a characteristic shoulder, i.e. a rehydration phase of long half‐time is followed by a phase of short half‐time. The experimental curves were fitted with parallel and series models of rehydration. In the parallel model two compartments are connected by resistances in parallel with the water source and rehydrate independently. In the series model one compartment is connected with the water source via a resistance and the second compartment is connected in series with the first by another resistance so that water entering the second compartment must pass through the first. Amongst nineteen experiments, ten could be fitted very closely by both the parallel and series models and nine could not be fitted

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11604553

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Abstract.The development and cell wall architecture of guard cells in the Cyperaceae were studied with light and electron microscopy. Development occurs along parallel files and results in a stomatal complex that consists of two guard cells each flanked by a subsidiary cell. The developmental pattern and general morphology are thus similar to that in the Gramineae. Several key differences, however, were observed. Wall synthesis in the Cyperaceae, as observed in the polarization and fluorescence microscope, occurs suddenly, within three to four complexes along a file, but is more gradual in the Gramineae. Mature cell walls in the Cyperaceae predominantly contain microfibrils oriented radially relative to the pore, while those in the Gramineae contain axial microfibrils. This difference was demonstrated in numerous species using freshly‐collected as well as preserved material. InCyperus esculentus, however, the alignment of microfibrils appears to be subject to environmental modification. Plants grown in the greenhouse contain guard cells with axial microfibrils, compared to the radial arrangement found in those grown in the field. In the former, wall is deposited gradually, as in the Gramineae. On return to more stressful conditions, radially micellated guard cells again develop. In each case, the cortical cytoplasm adjacent to areas where the wall is to thicken contains microtubules oriented parallel to the microfibril alignment characteristic of that treatment. These results are discussed in terms of the role of varied wall architecture in stomatal mechanics, the regulation of cell wall biosynthesis, and the evolutionary relationship of the Cyperaceae, Gramineae, and other tax

ISSN:0140-7791    

DOI:10.1111/1365-3040.ep11604559

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY