钙离子对盐胁迫下花生根系发育的调控

Regulation of calcium ion on root development of peanut under salt stress

花生(Arachis hypogaea)种子萌发期根系发育更易受到非生物胁迫的影响,无法正常生长甚至导致植株死亡,钙离子(Ca^(2+))与内源激素能够减轻非生物胁迫对植物造成的伤害。本试验以花生品种‘花育22’萌发期根系为试验材料,通过盐胁迫处理及外源施加乙二醇双(2-氨基乙基醚)四乙酸(EGTA)、氯丙嗪(CPZ)、氯化镧(LaCl_(3))等Ca^(2+)信号抑制剂(处理分别以NE、NC、NL表示)探讨盐胁迫下Ca^(2+)信号通路对花生根系发育的影响,以及对相关激素的调控作用。试验结果表明,外源施加Ca^(2+)信号抑制剂严重抑制根系的生长发育, NE、NC、NL处理后主根长度与盐胁迫处理相比明显缩短,分别缩短了73.17%、69.51%和58.54%,根系中抗氧化酶活性降低,其中SOD的活性变化最为明显,第五天时分别下降到86.68%、81.15%和77.43%,活性氧(ROS)过度积累,其中NL处理后第五天H_(2)O_(2)含量是盐胁迫处理的1.5倍,而根系活力在胁迫处理第一天分别下降了98.88%、96.98%和97.32%;相比盐胁迫, NE、NC、NL处理后花生Ca^(2+)信号通路相关基因以及内源激素相关基因的表达显著受到抑制,相应地,植物内源激素等合成受阻,其中胁迫响应激素ABA含量下降最显著,分别是盐胁迫处理的8.32%、23.62%和27.67%,表明Ca^(2+)信号通路可能通过影响内源激素的合成参与盐胁迫响应。

The development of roots of peanut(Arachis hypogaea) during seed germination were sensitive to abiotic stress, causing roots growth arrested and even death. Calcium(Ca^(2+)) and endogenous hormones were thought to alleviate abiotic stress injury to plants. In the present work, peanut roots of ‘Huayu 22’ were used as the test materials. Ca^(2+) signal inhibitors, i.e. ethylene glycol bis(2-aminoethyl ether) tetra acetic acid(EGTA), Chlorpromazine(CPZ) and Lanthanum(Ⅲ) chloride(LaCl_(3)) were applied under salt stress treatment(expressed by NE, NC, NL, respectively) to explore effects of Ca^(2+) signal on peanut roots development and regulation of related hormones under salt stress. The results showed that exogenous Ca^(2+) inhibitors combined with salt stress can inhibit the growth and development of the roots. The length of the main root treated with NE, NC and NL was absolutely shorter than that of salt stress, which was shorten by 73.17%, 69.51% and 58.54%, respectively. And the activity of antioxidant enzymes of the roots treated by NE, NC, NL also decreased, among which, the activity of SOD changed the most obviously in 5th day, and decreased to 86.68%, 81.15%, 77.43%, respectively. Accordingly, more excessive reactive oxygen species(ROS) accumulated, e.g. especially, the content of H_(2)O_(2) treated with NL was 1.5 times that of salt stress, and the roots activity was reduced by 98.88%, 96.98% and 97.32% respectively on the 1st day of treatment. Simultaneously, compared with salt stress, the expression of Ca^(2+) signal transduction pathway-related genes, and the endogenous hormone-related genes were clearly reduced. Accordingly, the synthesis of plant endogenous hormones were hinderedof which the ABA content decreased evidently(8.32%, 23.62% and 27.67% respectively). These results showed that Ca^(2+) signal pathway may be involved in response to salt stress by affecting the synthesis of plant endogenous hormones.