UV-B 辐射对番茄花粉生活力的影响与内源激素和多胺的关系

以成熟期不同的两个番茄品种同辉(早熟型)和霞光(晚熟型)为试材, 模拟兰州地区12%和20%臭氧层减薄时增强的UVB辐射(分别为T1=2.54 KJ.m-2.d-1和T2=4.25 KJ.m-2.d-1), 研究了大田条件下增强UV-B辐射对其花粉生活力的影响以及雄蕊中4种内源激素(IAA、GAs、ZR和ABA)和多胺(Put、Spm和Spd)及脯氨酸的变化。结果表明: 辐射抑制了同辉的花粉萌发和花粉管伸长, 但只降低了霞光的花粉萌发率; 两种辐射明显降低了两品种番茄雄蕊中的GAs含量, 同时造成同辉雄蕊中Put和Spd含量明显增加, Spm和Put/Spd+Spm比值显著降低; 霞光中3种多胺含量都显著减少, 导致高辐射时Put/Spd+Spm比值上升; 同辉番茄雄蕊的脯氨酸含量不受影响, 但高辐射使霞光番茄雄蕊的脯氨酸含量降低。实验表明, 两品种番茄花粉生活力的变化与增强UV-B 辐射下雄蕊中GAs水平、Spm含量以及脯氨酸含量的减少有关。雄蕊中多胺和脯氨酸含量变化对UVB辐射的响应说明霞光品种对UV-B辐射更敏感。

Effects of Enhanced UV-B Radiation on Pollen Activities of 2 Tomato Cultivars in Terms of Endogenous Hormone,Polyamine and Proline Levels in Stamens

The effect of enhanced UV-B radiation on pollen activities, endogenous hormone .(indole-3-acetic acid (IAA), gibberellic acid (GA), zeatin riboside (ZR), abscisic acid (ABA)) content and free polyamine and proline levels was studied in stamens of 2 tomato cultivars, Tonghui (TH) and Xiaguang (XG), which differ in ripening date. Cultivars were exposed to UV-B radiation at ambient (as a control), ambient plus 2.54 KJ.m-2.d-1 (T1) and ambient plus 4. 25 KJ.m-2.d-1 (T2) levels (simulating a 12% and 20% ozone depletion, respectively, at Lanzhou, 36°N, 103°E, at summer solstice) under field conditions. Both pollen germination and pollen tube growth were inhibited in TH, whereas only pollen germination was affected in XG with 2 doses of UV-B radiation. Endogenous GA level declined markedly in stamens of both cultivars. In stamens of TH, both Put and Spd levels increased, whereas Spm level and the ratio of Put to Spd+Spm decreased. In stamens of XG under T2 treatment, Decreased Put, Spm and Spd content resulted in a high ratio of Put to Spd+Spm in stamens of XG under T2 treatment. The proline level did not change in stamens of TH but decreased in stamens of XG with high UV-B radiation. Thus, change in pollen activity was associated with reduced GA, Spm and proline levels caused by enhanced UV-B radiation in stamens of both tomato cultivars. Change in polyamine and proline levels in response to UV-B radiation indicated that XG might be more sensitive to UV-B stress.