青藏高原药用植物唐古特山莨菪和唐古特大黄光合作用对强光的响应  

The Responses of Photosynthesis to Strong Light in the Medicinal Plants Anisodus tanguticus (Maxim.) Pascher and Rheum tanguticum Maxim. on the Qinghai-Tibet Plateau

作　　者：师生波[1] 王学英[1] 李惠梅[1] 韩发[1] 

机构地区：[1]中国科学院西北高原生物研究所,西宁810001

出　　处：《植物生理与分子生物学学报》2006年第3期387-394,共8页Journal Of Plant Physiology and Molecular Biology

基　　金：国家自然科学基金课题(No.30170154);国际科技合作重点项目计划(No.2002CB714006);中科院知识创新项目(No.KSCX2-1-07);国家中西部专项基金(No.2001BA901A47)资助。~~

摘　　要：与唐古特大黄相比,唐古特山莨菪的表观光合量子效率(AQY)较高,但最大净光合速率(Pmax)较低。在光强小于1200μmolm-2s-1时,后者用于碳同化的电子传递占总光合电子传递的比例(JC/JF)比前者高,而分配于光呼吸的电子传递(JO/JF)及Rubisco氧化和羧化速率的比值(VO/VC)则相反;光强大于1200μmolm-2s-1以后两种植物的这些参数都趋向稳定。随光强增加,后者叶片吸收光能分配于热耗散(D)的增加斜率较前者高,表明两高山植物对强辐射的适应方式略有不同。加强光呼吸途径的耗能代谢和PSII天线热耗散份额是唐古特山莨菪适应高原强辐射的主要方式,而提高叶片光合能力则是唐古特大黄的一种适应方式。Photosynthetic electron transport and light energy allocation were studied in the alpine plants Anisodus tanguticus （Maxim.） Pascher and Rheum tanguticum Maxim. ex Balf on the Qinghai- Tibet Plateau by using gas exchange and chlorophyll fluorescence. The results indicated that apparent quantum yield （AQY） of leaves of A. tanguticus was marginally higher than that of R. tanguticum although it had a lower maximum net photosynthetic rate （Pmax）- The net photosynthetic rate （Pn） of A. tanguticus was higher than R. tanguticum within the range of middle photosynthetic photon flux density （PPFD）. However, the Pn in R. tanguticum increased concomitantly with PPFD and did not appear to show light saturation of P, even under 2 000 μmol·m^-2·s^-1 which is similar to full light in summer （Fig. 1）. Increasing the PPFD to 1 200μmol·m^-2·s^-1 decreased the ratio of carboxylation rate to total photosynthetic electron flow rate （JC/JF） although increased the ratio of photorespiration （JO/JF） for both species. Both JC/ JF and JO/JF stabilized with a PPFD of more than 1200 μmol·m^-2·s^-1（Fig.2）. The changes in the ratios of Rubisco oxygenation to carboxylation （Vo/Vc） were similar to changes to JO/JF （Fig.3）. The increase of thermal energy dissipation （D） in A. tanguticus was higher than R. tanguticum with increased PPFD （Fig.4）. It can be concluded that the two species adopt different mechanisms to cope with increased solar radiation. Increasing the fractions of PSII thermal energy dissipation and electron transport through photorespiration were the main adaptations in A. tanguticus. Enhancement of photosynthetic capacity with increased PPFD to balance the higher light energy absorbed by leaves is considered the main adaptation for R. tanguticum.

关 键 词：青藏高原 高山植物 药用植物 光合电子传递 光能分配 

分 类 号：S567.239[农业科学—中草药栽培]