外源亚精胺对高温胁迫下萝卜幼苗生长发育的影响

Effects of Exogenous Spermidine on Growth and Development of Radish Seedlings Under High Temperature Stress

为探索亚精胺(Spd)对高温胁迫下萝卜幼苗生长的影响,解决萝卜高温生长受抑制的问题,以‘满身红’(耐热型)萝卜为试验材料,采用水培培养,在3叶1心时,将幼苗放入温光培养箱中进行昼夜40℃/30℃的高温胁迫处理,并在不同的处理时间里喷施1 mmol/L Spd。通过测定幼苗生长量、叶片叶绿素含量、丙二醛、抗氧化酶活性等抗逆指标,研究高温对萝卜幼苗生长发育的影响以及Spd对幼苗生长的促进作用。结果表明,随着高温处理时间的延长,植株生长受到极大地抑制,叶绿素、可溶性蛋白质出现大幅度下降,MDA含量升高,过氧化酶活性出现先升高最后降低的规律。喷施Spd能有效促进萝卜幼苗的生长,提高叶绿素和可溶性蛋白质含量,降低MDA的含量,增强过氧化酶的活性,达到清除细胞内产生的活性氧、维持细胞膜结构和细胞内物质的稳定的目的,最终提高萝卜抗高温能力。

The experiment was carried out to study the mitigating effects of spermidine（Spd） on radishseedling growth under high temperature stress, thus to solve the inhibition of radish growth under hightemperature. The heatproof radish‘Manshenhong’was investigated with its water culture seedlings in threeleaves and one half leaf period. The radish seedling was exposed to high temperature（40℃/30℃） dayalternating with night in TPS incubator, and 1 mmol/L Spd was sprayed on the radish seedling in different time.By measuring the stress physiological index of the seedling growth, the photosynthetic pigments content inleave, MDA, and the activity of antioxidant enzymes, the authors investigated the impact of high temperaturetreatment on radish seedling and the accelerating effect of Spd on radish seedling. The results showed that withthe increasing duration of high temperature stress, the seedling growth was significantly inhibited, the amountof photosynthetic pigments content in leaves and soluble protein content of seedlings decreased, the amount ofMDA increased, and the antioxidant enzyme activities increased first, and decreased finally. Exogenous Spdspray could promote the seedling growth. Suitable Spd concentration increased the amount of photosyntheticpigments content in leaves and soluble protein content, decreased the content of MDA, enhanced the activities of photosynthetic pigments. The Spd concentration also obliterated the reactive oxygen species in the cell, andmaintained the stability and integrity of cell membrane structure and the materials in the cell. The resultsabove indicated that Spd enhanced high temperature tolerance of radish seedlings.