干旱胁迫对不同类型红花品种（系） 苗期生理生化特性的影响

为筛选抗旱品种提供依据，本试验从14份红花品种中筛选出2个抗旱品种（PI401470和PI401477 ）和2个干旱敏感型品种（系）（PI560169和川红1号），并以此4份品种（系）为材料，研究干旱胁迫对红花幼苗光合、渗透调节物质和抗氧化物保护酶等生理生化特性的影响。结果表明，干旱胁迫下，4个红花品种（系）叶片净光合速率（Pn）、气孔导度（Gs）、胞间CO2浓度（Ci）和蒸腾速率（Tr）均呈不同程度的下降趋势，且品种间差异显著（P﹤0.05）；抗旱红花品（系）的各光合特性指标降幅均低于敏感型红花品种（系）。干旱胁迫条件下，渗透调节物质可溶性糖、可溶性蛋白质、脯氨酸含量均上升，保护性酶SOD、POD和CAT活性也均呈升高趋势，且抗旱型红花品种（系）的增长率高于敏感型品种（系）；抗旱型品种（系）MDA含量增长率低于敏感型品种。对11项指标进行主成分分析，提取了2个主成分，以净光合速率、气孔导度、胞间CO2 浓度、蒸腾速率、SOD活性和CAT活性为第一主成分，以可溶性蛋白质和脯氨酸为第二主成分的抗旱性鉴定指标，累计贡献率达89.50％。

Effect of drought stress on photosynthetic characteristics and physiological and biochemical traits of different safflower varieties (lines)

To screen the drought-tolerant Carthamus tinctorius L. genotypes growing in Sichuan Province of China, the influences of drought stress on photosynthetic characteristics, contents of osmoregulation substance, protective enzyme activities and the other physiological characteristics of two drought-tolerant and two drought-sensitive varieties were studied at safflower seedling stage by drought stress. The results showed that the net photosynthetic rate, stomatal conductance, intercellular CO2 concentration and transpiration of 4 safflower varieties declined under the drought stress, and the difference among the different varieties was significant (P﹤0.05). The decrease of photosynthetic characteristics of drought-tolerant varieties (lines) was lower than that of the drought-sensitive varieties (lines). The contents of permeability regulation substance of leaves such as soluble sugar, soluble protein, proline and the protective enzyme activities of SOD, POD and CAT were all increased in 4 varieties (lines) under drought stress. Moreover, the increase rate of drought-tolerant varieties was higher than that of drought-sensitive. The increase rate of MDA content in drought -tolerant varieties was also lower than that in drought-sensitive varieties. Two principal components were obtained by principal component analysis of 11 indexes, and the cumulative contribution rate was 89.50%. The net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, transpiration rate, SOD and CAT activities were used as the primary principal components of drought resistance index, while soluble protein and proline were used as the secondary principal component of drought resistance identification index.