Research on biosynthesis of UV absorbing substances in epidermis of plant leaves and their function to protect the plants from injury by UV radiation.

植物叶片表皮紫外线吸收物质的生物合成及其保护植物免受紫外线伤害的功能研究。

基本信息

批准号：
63540543
负责人：
KONDO Noriaki
金额：
$ 1.41万
依托单位：
The National Institute for Environmental Studies
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

项目摘要

Radiation of ultraviolet-B (UV-B) region (280-320nm) causes growth retardation of plants and visible injury such as chlorosis on leaf surface. These damages seem to be under the control of the environmental conditions during plant growth. The extent of damage is thought to depend on the differences of content of ultraviolet (UV) absorbing substances in the epidermis of plant leaves. In the present studies, the content of UV absorbing substances in leaf epidermis of pea mutant and broad bean was compared with resistance of these plants to ultraviolet-C (UV-C). In the next experiments, effects of UV-B radiation on first leaves of cucumber plants and effects of environmental conditions on the sensitivity of plant to UV-B were examined. Effects of UV-B radiation on enzymic properties of glutathione reductase (GR), rate-limiting enzyme in metabolic pathway to detoxify hydrogen peroxide, were also examined. Outline of the results obtained are as follows.(1)Epidermis of pea leaves has flavono … More id-like substances, which have absorbance peaks at 260 and 320 ns and little absorbance in visible region. The content of these substances showed a parallelism with resistance to UV-B radiation.(2)UV-B irradiation caused the growth retardation of cotyledons and first leaves of cucumber seedlings and chlorosis on first leaves at 20ﾟC. But, the growth retardation could not be found on the irradiation at 25ﾟC, though chlorosis was observed.(3)high intensity of ultraviolet-A (UV-A) restored the retardation of growth of first leaves when it was given together with UV-B. But, chlorosis caused by UV-B was not restored by UV-A radiation.(4)UV-B radiation lowered the affinity of GR in cotyledons to substrates. It was clarified in the present work that the sensitivity of cucumber plants to UV-B was dependent on temperature and light condition at the time of UV-B radiation. Mechanism of plant damage caused by UV-B radiation, defense mechanism to UV-B and, in addition, effects of environmental conditions on biosynthesis of UV absorbing substances must be more investigated. Less

紫外线B（UV-B）区域（280-320nm）的辐射会导致植物生长迟缓和明显的损伤，例如叶面失绿，这些损伤的程度似乎受到植物生长期间环境条件的控制。据认为，植物叶片表皮中紫外线吸收物质含量的差异决定了其对植物的损害。将菜豆与这些植物对紫外线 C (UV-C) 的抗性进行了比较。在接下来的实验中，研究了 UV-B 辐射对黄瓜植物第一片叶子的影响以及环境条件对植物对 UV-B 敏感性的影响。还检查了 UV-B 辐射对谷胱甘肽还原酶 (GR) 的酶特性的影响，谷胱甘肽还原酶是代谢途径中过氧化氢解毒的限速酶，所得结果概述如下。 (1)豌豆叶表皮含有类黄酮类物质，在260和320 ns处有吸收峰，在可见光区吸光度很小，这些物质的含量与UV-B辐射的抵抗力呈平行关系。 (2)20℃下UV-B照射导致黄瓜幼苗子叶和初生叶生长迟缓,初生叶失绿。但是，在25°C的照射下，虽然观察到了失绿现象，但并未发现生长迟缓。(3)高强度的紫外线A(UV-A)与同时给予时，恢复了第一片叶子的生长迟缓。但是，UV-A辐射不能恢复UV-B引起的失绿。(4)UV-B辐射降低了子叶中GR对基质的亲和力。目前的工作表明，黄瓜植物对 UV-B 的敏感性取决于 UV-B 辐射时的温度和光照条件，UV-B 辐射对植物造成伤害的机制、对 UV-B 的防御机制，此外。，环境条件对紫外线吸收物质生物合成的影响必须更多地研究。