几种热带雨林与荒漠植物暗呼吸作用对高CO_2浓度的响应

The response on dark respiration of some tropical rain forest and coastal desert plant species to the elevation of CO 2 concentrations

使用 Ｌ Ｉ６４００ 便携式光合作用测定系统测定了美国生物圈二号内长期生长在高 Ｃ Ｏ２ 浓度（＞ １５００μｍ ｏｌ／ｍ ｏｌ）下 ５种热带雨林植物与 ５ 种荒漠植物暗呼吸强度的变化。结果表明：在 ３５０～４００μｍ ｏｌ／ｍ ｏｌ下 ５ 种雨林植物的平均暗呼吸强度为（０５６±０１９）μｍ ｏｌ Ｃ Ｏ２／ｍ ２·ｓ；荒漠植物平均为（０９８±０７２）μｍ ｏｌ Ｃ Ｏ２／ｍ ２·ｓ。在 Ｃ Ｏ２ 浓度升高时大部分 Ｃ３ 植物暗呼吸作用升高，并呈一定的线形关系。当 Ｃ Ｏ２ 浓度加倍时，雨林植物暗呼吸强度升高６１％ ；荒漠 Ｃ３ 植物升高１３４％ ，而 Ｃ４ 植物变化不明显或略有下降。因而认为，长期高 Ｃ Ｏ２ 浓度可促进 Ｃ３ 植物的暗呼吸作用。

The dark respiration of five tropical rain forest and five coastal desert plant species experienced in very high CO 2 concentrations(>1500μmol/mol)in Biosphere 2 for more than 4.5 years,was studied using a portable LI 6400 Photosynthesis system.The result showed that the average dark respiration of the rain forest species was (0 56±0 19)μmol CO 2/m 2·s under near ambient CO 2 concentration (350～400μmol/mol),and that of the desert species was(0 98±0 72)μmol CO 2/m 2·s.The dark respiration of both the rain forest and the desert C 3 species showed increases of 61% and 134% respectively,when CO 2 concentration was doubled.But the C 4 desert species appeared little change or somehow decrease.This could be ascribed to the fact that more carbohydrate compounds that dark respiration required were produced because of the enhencement of photosynthesis,and more energy and material were needed as a result of the fast growth of the C 3 species under a high CO 2 environment.So the respiration such as the maintenance respiration may be increased in order to provide the energy and material needed.