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Relations between Photosynthetic Rate during Low Temperature Period and Over-wintering in Tropical Grasses.

热带草类低温期光合速率与越冬的关系。

基本信息

批准号：
61560016
负责人：
KOJI Ito
金额：
$ 1.22万
依托单位：
Miyazaki University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

项目摘要

In order to obtain fundamental informations for improving the over-wintering abilities of tropical grasses in southern regions of Japan, some investigations were done. Results obtained were summarized as follows. The patterns of the time course changes of population photosynthetic abilities during the period from October to next April were different among 8 grass species from the genus of Panicum, Pennisetum and Setaria. However, the species differences in the levels or patterns of changes of photosynthetic ability during the period before March were not definitely related to the species differences in the photosynthetic abilities at the early period of spring regrowth which commenced at eraly march.In Dallisgrass and Bahiagrass, the plant photosynthetic ability at the early period of spring regrowth was clearly related to the degree of suppression of photosynthetic rate by shading or defoliation during autumn or winter. The more intense the suppression, the lower was the photosynthetic ability at spring. In Rhodesgrass and Makarikarigrasss, however, such relations as seen in the former two grasses, were not observed. In comprison to the latter two grasses, the percentage of the numbers of tillers surviving throughout the winter, was higher in the formers. From these facts, it was infered that the amount of reserve materials, previously produced mainly by photosynthesis, was more liable to limit the rate of early growth of tillers at the regrowth period in the formers than in the latters.Thus, the photosynthetic rate during the low temperature perid affected the photosynthetic ability at spring regrowth in the grasses with a high over-wintering ability, such as Dallisgrass or Bahiagrass.

为了获得提高热带牧草在日本南部地区越冬能力的基础资料，对其进行了调查。所获得的结果总结如下。从10月到次年4月，狗尾草属、狼尾草属和狗尾草属8种牧草群体光合作用能力的时间进程变化规律不同。但3月份以前植物光合作用水平或变化模式的差异与3月初开始的春季再生初期的物种差异并不一定相关。在达利斯草和百喜草中，春季再生初期的植物光合作用能力与秋冬季遮荫或落叶对光合速率的抑制程度有明显的相关性。抑制越强烈，春季的光合作用能力越低。然而，在Rhodesgras和Makarikargrasss中，没有观察到在前两种草中看到的这种关系。与后两种牧草相比，前两种牧草的越冬成活率较高。由此推测，以前主要由光合作用产生的后备物质，前者比后者更容易限制分蘖在再生期的早期生长速度，因此，在越冬能力较强的牧草中，低温时期的光合速率影响了春季再生期的光合作用能力。