黄腐酸和甜菜碱预处理对干旱胁迫下平邑甜茶生理特性及光合的影响

该研究以平邑甜茶Malus hupehensis(Pamp.)Rehd.]2年生实生苗为材料,通过盆栽试验于干旱处理前3d分别连续喷施黄腐酸(FA)、甜菜碱(GB)和复配(FA+GB),并以清水为对照(CK)进行预处理,比较分析不同预处理对干旱胁迫下平邑甜茶的生理及光合特性变化,探讨FA和GB对平邑甜茶的抗旱生理机制。结果显示:(1)与对照相比,FA、GB和FA+GB预处理均能够显著提高平邑甜茶叶片相对含水量,且FA的保水性效果最佳。(2)3种预处理均可显著促进干旱胁迫下叶片可溶性蛋白、可溶性糖和脯氨酸含量增加,且FA+GB预处理后在干旱胁迫下叶片可溶性糖和脯氨酸累积量显著高于单施FA或GB。(3)3种预处理均可显著提高干旱胁迫下平邑甜茶幼苗的SOD、POD、CAT活性,并显著降低MDA的积累速度及其累积量,且以FA+GB预处理的MDA含量最低、抗氧化酶活性最高。(4)GB和FA+GB预处理下平邑甜茶的净光合速率、瞬时水分利用率显著高于CK和FA,且FA+GB处理下改善光合特性的效果最佳,GB次之。研究表明,单独喷施黄腐酸和甜菜碱及两者配施预处理均能够增加干旱胁迫下平邑甜茶的渗透调节物质和相对含水量,提高叶片的保水性,调节抗氧化物酶活性,降低丙二醛含量,增加细胞膜稳定性,改善光合性能,进而提高平邑甜茶的抗旱能力,且以复配喷施(FA+GB)预处理的效果最好。

Effects of Fulvic Acid and Betaine Pretreatment on Physiological Characteristics and Photosynthesis of Malus hupehensis under Drought Stress

The pot experiment was conducted to compare and analyze the changes of the physiological and photosynthetic characteristics of 2 year old Malus hupehensis (Pamp.) Rehd. seedlings of different pretreatments by three consecutive days spraying fulvic acid(FA), glyeine betaine(GB) and combination of fulvic acid and glyeine betaine (FA+GB) and with water as control (CK) pretreatment before drought treatment to explore the physiological drought mechanism of FA and GB for M. hupehensis. The results showed that: (1) compared with the control, FA, GB and FA+GB pretreatment can significantly improve the relative water content in leaves of M. hupehensis, and the water retaining effect of FA was the best. (2) Under drought stress, the three pretreatments could significantly increase the contents of soluble protein, soluble sugar and proline; and the soluble sugar and proline accumulation of the FA+GB were significantly higher than that of the single application of fulvic acid and betaine treatment. (3) Under drought stress, all the three pretreatments could significantly increase the SOD, POD and CAT activities of seedlings and significantly reduce the accumulation rate and content of MDA. While the pretreatment of FA+GB had the lowest MDA content and the highest antioxidant enzyme activity. (4) The net photosynthetic rate and instantaneous water use efficiency of M. hupehensis treated with GB and FA+GB pretreatments were significantly higher than those of CK and FA. And the photosynthetic characteristics of FA+GB were the best, followed by GB. The results showed that under the drought stress, spraying fulvic acid, glyeine betaine and combination of fulvic acid and glyeine betaine on M. hupehensis leaves could increase the osmotic adjustment substance, the water holding capacity and the relative water content, regulate the activities of antioxidant enzymes, reduce malondialdehyde content, increase cell membrane stability, and could also improve the photosynthetic performance; thereby enhance the drought resistance of M. hupehensis, and effect of pretreatment with compound spraying (FA+GB). Was the best Pamp.