Time‐course of uptake of dissolved inorganic carbon through willow roots in light and in darkness
Time‐course of uptake of dissolved inorganic carbon through willow roots in light and in darkness
复制标题
光照和黑暗下柳根吸收溶解无机碳的时间过程
DOI：
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发表时间：
1989
期刊：
影响因子：
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通讯作者：
S. Lapinjoki
中科院分区：
文献类型：
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作者：
A. Vuorinen;E. Vapaavuori;S. Lapinjoki
在光照和黑暗条件下，测定了柳树根系对营养液中溶解无机碳(DIC)的吸收，并测定了DIC在植物体内的分布。还研究了运输系统能否通过与溶解的无机碳预先孵育而被激活。
柳树(Salix cv.)用0.74 mM NaHCO3或不加0.74 mM NaHCO3预培养2天。预培养后，将未标记的或[14C]标记的NaHCO3注入培养基中，在光照或黑暗中分别在1、5、10和24小时后，将植株切成块放入液氮中，冷冻干燥，在燃烧室中燃烧。
在光照和黑暗条件下，~(14)C都通过根运输到新梢和叶片，但在24小时取食结束时，~(14)C在黑暗中的掺入量仅为光中的一半。在光照和黑暗条件下，柳树植株各部位的~(14)C含量均随时间的延长而增加。在光照条件下，插穗和枝条的标签率最高。在黑暗中，在未激活和激活处理的插条中都检测到了总标记的一半以上。
在枝条的中部，在5和10h后标记最强，但在24h后14C向枝条的底部移动。在所有取食时间的叶片中，大部分放射性物质都被合并到枝条上部完全开放的幼叶中。在生长介质中用未标记的NaHCO3预培养对DIC的吸收速率没有明显的影响，无论是在光照还是在黑暗中。
Uptake of dissolved inorganic carbon (DIC) from a nutrient solution by willow roots was measured in light and darkness and the distribution in the plant of DIC taken up by the roots was determined. It was also studied whether the transport system could be activated by preincubation with dissolved inorganic carbon.
Willow plants (Salix cv. Aquatica gigantea) grown in hydroponic culture media were preincubated for 2 days with or without 0.74 mM NaHCO3. After preincubation, either unlabelled or [14C]-labelled NaHCO3 was injected into the media and after 1, 5, 10 and 24 h either in light or in darkness the plants were harvested in pieces into liquid nitrogen, lyophilized and burned in a combustion chamber.
14C was transported through the roots to the shoots and leaves both in light and in darkness, although incorporation of 14C in darkness was only half of that in light at the end of the 24-h feeding period. Both in light and in darkness the amount of 14C increased in all parts of willow plants with time. In light the rate of labelling was highest into cuttings and shoots. In darkness more than half of the total label was detected in cuttings of both the non-activated and the activated treatments.
In the shoots the middle part was most strongly labelled after 5 and 10 h, but after 24 h 14C moved towards the base of the shoot. In the leaves at all feeding times most radioactivity was incorporated into the young, fully open leaves on the upper part of the shoots. Preincubation of plants with unlabelled NaHCO3 in growth media had no clear effect on the rate of DIC uptake either in light or in darkness.