摘要:

AbstractThe initial and subsequent distribution of22Na,43K,86Rb,134Cs,32P,35S,45Ca,65Zn and85Sr in bean plants, following leaf and root uptake was studied under controlled environmental conditions. Autoradiographic and counting methods reveal vascular connections between leaves and roots and two patterns of distribution in the leaves following root uptake are reported. Distribution following treatment of specific parts of the leaves or roots points to a morphological unity in the bean plant. A possible circulation pattern for some ions is discussed.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1968.tb07245.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractProofs of different kind are presented of the existence of highly active bacteria producing IAA from tryptophan on plant surfaces and in plant homogenates.Both homogenates and washing solutions of nonsterile pea plant parts are active in producing IAA from tryptophan. Activity is much enhanced by the addition of glucose or by preincubating the preparations; it is abolished by sterile filtration, by some bactericidic and bacteriostatic substances, by chloramphenicol, streptomycin, and albucid (penicillin being only partly effective). Preparations of sterile plants do not produce IAA from tryptophan within the detection limit of the Salkowski test. The bacteria are even present on seed surfaces, in the air, and in aceton or ammonium sulfate precipitations of homogenates.Main products of the bacterial tryptophan conversion, as demonstrated by paper chromatography, are indolepyruvic acid, indoleacetic acid, indolecarboxaldehyde, and indolecarboxylic acid. In presence of glucose indolepyruvic acid is by far dominating.Many hitherto known results about tryptophan conversion to IAA by higher plants are likely to be falsified by epiphytic bacteria.

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1968.tb07246.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

RésuméUn RNA ribosomal de faible poids moleculaire, distinct du RNA de transfert et analogue à celui qui a été identifie dans les cellules bactériennes et dans certaines cellules animates, a été mis en evidence chez les végétaux. Ce RNA ribosomal de faible poids moléculaire a été séparé du RNA de transfert. Les résultats sont discutés en relation avec des hypothèses récemment émises sur le r

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1968.tb07247.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractWater relations of a number of mangroves and other halophytes were studied. All mangroves had high negative pressure in the xylem (30 to 60 atm) which more than balances the osmotic pressure of the seawater (25 atm). Freezing a short stem section of an attached twig always resulted in wilting caused by eavitation of the tensile sap. Semipemeable membranes in the leaves remained functioning in spite of being iced or healed (50°C), or being poisoned by dinitrophenol and carbon monoxide (13 atm). Chloroform and ether ruptured the membranes.When some 40 atm pressure was applied to the root system of a decapitated seedling potted in seawater, a flow of nearly fresh water ensued. This separation kept on for hours in spile of chilling and poisoning with dinitrophenol or 20 atm carbon monoxide. A reversal of the gradient made roots lose water to the seawater. One may conclude, therefore, that mangroves separate fresh water from the sea by a simple non‐metabolic ultrafiltration process, in a system where high tension obtains in the xylem and where turgor of the living cells is produced by an active maintenance of high solute pressu

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1968.tb07248.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractThe growth characteristics of three types of tissue cultures of tobacco have been investigated. They are (i) pigmented and differentiated teratoma tissue; (ii) pigmented and non‐differentiated habituated tissue and (iii) non‐pigmented and non‐differentiated habituated tissue. All the tissues were grown on a 10 × White's medium without any exogenous supply of auxin.The comparative growth rate of the tissues was related to their nature of differentiation,viz., either organelle differentiation with chloroplast or organ differentiation with buds, leafy appendages,etc. Teratoma and pigmented habituated tissues had normal chlorophyll and carotenoid contents and showed more favorable growth in light than in the dark. The pigmented tissues showed a higher protein content than the non‐pigmented tissues irrespective of whether they were of tumorous or normal origin. The pigmented tissues showed less dependence on sucrose availability in the medium than the non‐pigmented tissues. Recovery after sucrose starvation was higher in the pigmented tissues than in the non‐pigmented tissues.The results indicate that the growth rate of highly differentiated tissues is much slower than non‐differentiated tissues and that the pigmented tissues photosynthesize and survive on reserve food products manufactured as a result of photosynt

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1968.tb07249.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY