Showing papers on "Plant physiology published in 1971"

The nodulation and nitrogen fixation of isolated roots ofPhaseolus vulgaris L.

Abstract: At a concentration of 3%, carbon dioxide completely inhibits nodulation. Ethylene at concentrations of 0.4 ppm and above is extremely inhibitory towards nodulation. The gaseous emanations from isolated root cultures, when permitted to accumulate, completely prevent nodulation and also inhibit the nitrogen fixation of existing nodules. Evidence is presented which suggests that ethylene is the active principle of the gaseous emanations.

Physiology of Oil Seeds: II. Dormancy Release in Virginia-type Peanut Seeds by Plant Growth Regulators

Abstract: Germination, ethylene production, and carbon dioxide production by dormant Virginia-type peanuts were determined during treatments with plant growth regulators. Kinetin, benzylaminopurine, and 2-chloroethylphosphonic acid induced extensive germination above the water controls. Benzylaminopurine and 2-chloroethylphosphonic acid increased the germination of the more dormant basal seeds to a larger extent above the controls than the less dormant apical seeds. Coumarin induced a slight stimulation of germination while abscisic acid, 2,4-dichlorophenoxyacetic acid, and succinic acid 2,2-dimethylhydrazide did not stimulate germination above the controls. In addition to stimulating germination, the cytokinins also stimulated ethylene production by the seeds. In the case of benzylaminopurine, where the more dormant basal seeds were stimulated to germinate above the control to a larger extent than the less dormant apical seeds, correspondingly more ethylene production was induced in the basal seeds. However, the opposite was true of kinetin for both germination and ethylene production. When germination was extensively stimulated by the cytokinins, maximal ethylene and carbon dioxide evolution occurred at 24 and 72 hours, respectively. Abscisic acid inhibited ethylene production and germinaton of the seeds while carbon dioxide evolution was comparatively high. The crucial physiological event for germination of dormant peanut seeds was enhancement of ethylene production by the seeds.

Nematodes and other pathogens in auxin-related plant-Growth disorders

Abstract: INTRODUCTION .................................................................................................. 1 BACTERIA, FUNGI, VIRUSES ................................................................................ 1 INSECTS ................................................................................................................... 2 NEMATODES .......................................................................................................... 2 AUXIN LEVELS IN MODIFIED HOST TISSUE .................................................. 5 Bacteria, Fungi, Virus ......................................................................................... 5 Insects .................................................................................................................... 6 Nematodes ............................................................................................................. 7 OTHER PLANT-GROWTH REGULATORS ......................................................... 11 ORIGIN OF AUXIN ................................................................................................. 12 ETIOLOGY .............................................................................................................. 17 LITERATURE CITED .......................................................................................... 19

Effect of moisture stress on metabolic products and ions accumulation

Abstract: Estimations of the metabolic products and accumulated ions were made at the different stages of development of a number of native and introduced plant species grown under different conditions of moisture stress corresponding to different levels of water supply equivalent to 125, 200, 275 and 350 mm.

On the mechanism of nitrate uptake by plant roots: I — Nitrate influx and nitrogen compounds efflux as affected by some factors

Abstract: A study has been made on the influx and outflux of nitrogen compounds by the excised roots of barley, wheat and peas. A two way movement of nitrogen compounds was found to occur between root and external medium. Factors such as initial N content in the roots, species of plant and external concentration of N highly affect the extent to which this two-way movement proceeds. Further investigations are needed for more understanding of the nitrogen balance between plant roots and external medium.