Physiological and Ecological Analyses of Shade Tolerance of Plants 2. Growth of Dark-treated Green-gram under Varying Light Intensities
Year: 1962
Type: article
Abstract: Four day etiolated green-gram plants, of which stems elongated enormously at the cost of leaf growth, were grown under varying light intensity (100, 75, 50, 30 and 20% of daylight), and their growth response to the shading was determined and compared with that of untreated green-gram plants.1. The trends of growth, in dry weight as well as in leaf area, of the dark-treated DN- and DO-series were similar to those of the untreated N- and O-series.But the final values of plant weight or leaf area were markedly small in the dark-treated as compared with those of the untreated.2. The relations of the relative growth rate (RGR), the net assimilation rate (NAR) and the leaf area ratio (LAR) to the varying light intensity showed in the dark treated plants also the trends similar to those of the untreated.3. The NARs in the earlier stages (Aug. 13-27) were much higher in the dark-treated series (especially in the 100, 75 and 50% plot) than those in the untreated series, while the LARs of the former were smaller in all the plots, and consequently the RGRs were scarcely affected by the dark-treatment. In the later stages, however, no difference in these three measures could be observed between the two series.4. In the initial three days (Aug. 11-13) the RGR of the DN-100 plants was low, 0.14mg/mg/day, as compared to 0.23mg/mg/day of the N-100. Such low RGR may bring about the low final plant weight of the DN- and DO-plants.5. The leaf area/leaf weight ratio (F/F) of the DN- and DO-plants increased markedly with decreasing illumination and gave nearly identical results with those of the untreated plants.6. The N- and O-plants maintained the C/F ratio, the ratio of the non-photosynthetic to the photosynthetic system, of 1.0-1.5 throughout the whole experimental period, while the DN- and DO-plants, placed in full daylight after 4 day dark treatment, dropped rapidly C/F ratio of 7-8 at first and then slowly, it approaching to a level of 1.0. The high C/F ratio should be largely responsible for the low RGR observed in the initial few days following the dark-period.
Source: Shokubutsugaku Zasshi
Institutions: Ibaraki University, The University of Tokyo
Language: English
Topic: Light effects on plants
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: bronze
OpenAlex ID: W2742983