干旱胁迫下外源物质对番茄幼苗活性氧代谢及光合作用的影响

Effects of exogenous substances on active oxygen metabolism and photosynthesis in tomato seedlings under drought stress

以番茄品种‘金棚一号’为试验材料,研究不同外源物质(10mmol/L CaCl2、5mmol/L GABA、0.5mmol/L Put、0.5mmol/L Spd)对干旱胁迫下番茄幼苗活性氧代谢及光合作用的影响。结果表明:与对照相比,干旱胁迫处理抑制了番茄幼苗的生长,使幼苗光合系统Ⅱ(PSⅡ)能力降低,叶片可溶性蛋白质含量降低,游离氨基酸及可溶性糖含量升高,活性氧代谢的变化造成MDA积累;外源物质CaCl2、GABA、Put、Spd均可提高幼苗的株高、茎粗、干重和鲜重以及叶片中可溶性蛋白质、游离氨基酸、可溶性糖含量,通过提高抗氧化酶(SOD、POD、CAT)活性,降低了O2.-产生速率、H2O2和MDA含量,维持较高的叶绿素荧光参数Fv/Fm、ΦPSⅡ、qP、ETR,从而在一定程度上缓解干旱胁迫对幼苗的伤害。平均隶属函数分析表明,不同外源物质缓解干旱胁迫的途径不同,外源添加Put处理缓解干旱胁迫的作用主要体现在促进植物生长方面,GABA处理则主要体现在减缓干旱胁迫对叶片光系统Ⅱ和活性氧代谢的伤害,Ca2+处理在增加渗透调节物质含量方面更为明显。

In this paper, the authors investigated the effects of different exogenous substances, 10 mmol/L CaC12, 5 mmol/L GABA, 0.5 mmol/L Put, 0.5 mmol/L Spd, on active oxygen metabolism and photosynthesis in tomato seedlings ＇Jin Peng No. 1 ＇ under drought stress. The results showed that, compared with CK, when tomato seedlings were grown under drought stress, plant growth, photosynthesis system Ⅱ（PSⅡ） and soluble protein content were re- stricted or reduced, and the contents of free amino acids and soluble sugar were increased. Meanwhile, the variation of active oxygen metabolism leaded to MDA accumulation. Seedlings grown with exogenous substances of CaC12, GABA, Put, and Spd under drought stress im- proved plant growth in height, stem diameter and root, and increased fresh weight, dry weight together with the contents of soluble protein, free amino acids and soluble sugar. The exoge- nous substances reduced the 02- production rate, decreased the contents of H202 and MDA byincreasing the activity of SOD, POD and CAT, and kept Fv/Fm, cI）psn , qp, ETR at high lev- els, so as to relieve the seedling damage under drought stress. The average subordinate func- tion analysis showed that different exogenous substances reacted drought stress in different ways： Put relieved the damage of drought stress mainly through improving plant growth, and GABA mainly through weakenning the harm to photosystem Ⅱ and active oxygen metabolism in leaves, however, Ca2＋ mainly through increasing the contents of osmoregulation substances.