大豆叶片CO_2补偿点和光呼吸的关系  

Relationship Between the CO_2 Compensation Point and Photorespiration in Soybean Leaves

作　　者：蔡时青[1] 许大全[1] 

机构地区：[1]中国科学院上海植物生理研究所,上海200032

出　　处：《植物生理学报（0257-4829)》2000年第6期545-550,共6页Acta Phytophysiologica Sinica

基　　金：国家重点基础研究发展规划项目 (No .G19980 10 10 0 );国家自然科学基金重点项目 (No .3 973 0 0 40 )资助

摘　　要：为了探讨CO2 补偿点 (Г)与光呼吸 (Rp)的关系 ,用CI 30 1光合气体分析系统观察了光强等因素对大豆叶片CO2 补偿点的影响。在高于生长光强的强光下 ,Г和Rp随着光强的增高而升高 ,实验表明这可能与强光下发生的无机磷限制有关 ;经 10mmol/L的甘露糖、0 .2 %PEG 6 0 0 0和 10mmol/L的DL 甘油醛处理后 ,Г显著上升 ,前两者使Rp下降 ,而后者使Rp上升 ;给叶片喂 5mmol/L的KH2 PO4 后 ,Г和Rp都降低。并且 ,衰老叶片的Г比刚完全展开的叶片高 ,但前者的Rp却比后者低。这些结果表明 ,光呼吸是影响CO2 补偿点的一个重要因素 ,但不是唯一因素 。Effects of several factors on the CO 2 compensation point (Γ) in soybean leaves were observed by using a CI 301 photosynthetic gas analysis system to elucidate the relationship between the CO 2 compensation point and photorespiration (Rp). Both the CO 2 compensation point and photorespiratory rate increased with increasing light intensities above growth light intensity (Fig.2). The change in the CO 2 compensation point was mainly due to phosphate limitation occurring under strong light as demonstrated by the phosphate feeding experiment (Fig.3). Mannose 10 mmol/L (Table 1), 0.2% PEG 6000 (Fig.5), and DL glyceraldehyde 10 mmol/L (Table 3) all raised the CO 2 compensation point in soybean leaves, but photorespiratory rate was decreased by mannose (Table 1) and PEG (Fig.5) treatment, and increased slightly by DL glyceraldehyde treatment. KH 2PO 4 5 mmol/L lowered both the CO 2 compensation point and photorespiratory rate in soybean leaves (Fig.4). Moreover, the CO 2 compensation point was higher in aging leaves than that in those just fully expanded, but photorespiratory rate was lower in the former than that in the latter (Table 2). These results indicate that photorespiration is an important factor affecting the CO 2 compensation point, but is not the sole one in C 3 plant leaves. The CO 2 compensation point always changes with the ratio of photorespiratory rate to carboxylation efficiency (CE) in the same direction.

关 键 词：CO2补偿点 磷限制 光呼吸 水分胁迫 大豆 

分 类 号：S565.1[农业科学—作物学]