摘要:

ABSTRACTSeedlings ofVicia fabaL. were grown in open‐top growth chambers at present (P=350μmol−1) and at elevated (E=700μmol mol−1) atmospheric CO2concentration. The effects of CO2enrichment on the first phase of growth after germination were examined over 45 d. There were no positive effects of CO2enrichment on growth of the seedlings during this early phase. No differences were observed in leaf area or in total dry weight. No differences were found in morphology or anatomy of the leaves. The numbers of stomatal and epidermal cells, thickness of leaf, of epidermis and of mesophyll cell‐layers were unaffected by CO2enrichment. Also, no differences were observed in leaf concentrations of chlorophyll, reducing carbohydrates or starch. These results contrast markedly with results from similar experiments on poplar hybrids andPhaseolus vulgarisobtained in the same growth facility. It seems that the intitial growth is under internal control such that the atmospheric CO2concentration has no effects. The lack of response in this case may be attributed to the presence and longevity of the large cotyledons which provided available substrate f

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1993.tb00849.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTRoots ofPisum sativumL. andZea maysL. were exposed to different moisture gradients established by placing both wet cheesecloth (hydrostimulant) and saturated aqueous solutions of various salts in a closed chamber. Atmospheric conditions with different relative humidity (RH) in a range between 98 and 86% RH were obtained at root level, 2 to 3mm from the water‐saturated hydrostimulant. Roots of Silver Queen corn placed vertically with the tips down curved sideways toward the hydrostimulant in response to approximately 94% RH but did not respond positively to RH higher than approximately 95%. The positive hydrotropic response increased linearly as RH was lowered from 95 to 90%. A maximum response was observed at RH between 90 and 86%. However, RH required for the induction of hydrotropism as well as the responsiveness differed among plant species used; gravitropically sensitive roots appeared to require a somewhat greater moisture gradient for the induction of hydrotropism. Decapped roots of corn failed to curve hydrotropically, suggesting the root cap as a major site of hydrosensin

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1993.tb00850.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTPrimary roots ofZea mayscv. Ageotropic are nonresponsive to gravity and elongate approximately 0.80 mm h−1. Applying mucilage‐like material (K‐Y Jelly) to the terminal 1.5 cm of these roots induces graviresponsiveness and slow elongation 28% (i.e. from 0.80 to 0.58mm h−1). Applying mucilage‐like material to one side of the terminal 1.5 cm of the root induces curvature toward the mucilage, irrespective of the root's orientation to gravity. Applying a 2‐mm‐wideband of mucilage‐like material to a root's circumference 8 to 10 mm behind the root cap neither induces gravicurvature nor affects elongation significantly. Similarly, applying mucilage‐like material to only the root cap does not significantly affect elongation or graviresponsiveness. Gravicurvature of mutant roots occurs only when mucilage‐like material is applied to the root/root‐cap junction. Reversing the caps of wild‐type and mutant roots produces gravitropic responses characteristic of the root cap rather than the host root. These results are consistent with the suggestion that gravitropic effectors are growth inhibitors that move apoplastically through mucilage betwee

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1993.tb00851.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Books reviewed in this article:ALGAE AND SYMBIOSES: PLANTS, ANIMALS, FUNGI, VIRUSES, INTERACTIONS EXPLORED.Edited by W. ReisserNITROGEN METABOLISM OF PLANTS.Edited by K. Mengeland D. J. Pilbeam

ISSN:0140-7791    

DOI:10.1111/j.1365-3040.1993.tb00852.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY