混合中性盐胁迫对金盏菊幼苗生长及光合生理的影响

Effects of Mixed Neutral Salt Stress on Growth and Photosynthetic Physiology of Calendula officinalis Seedlings

摘要:

为了解金盏菊（Calendula officinalis）幼苗对混合中性盐胁迫的响应，采用盆栽砂培法，对在NaCl和Na₂SO₄（摩尔比为9∶1）胁迫下其生长和光合特性的变化进行了研究。结果表明，低盐胁迫下（≤100 mmol L^-1），金盏菊幼苗通过提高抗氧化酶即超氧化物歧化酶（SOD）、过氧化物酶（POD）与过氧化氢酶（CAT）活性，降低膜酯过氧化产物丙二醛（MDA）含量，维持活性氧的代谢平衡与膜结构的完整性，使其可进行正常的光合作用，进而维持正常生长；当盐浓度≥200 mmol L^-1时，金盏菊幼苗的SOD、POD和CAT活性迅速下降，MDA含量迅速升高，显著影响其光合能力与生长发育。因此，金盏菊幼苗耐混合中性盐的阈值为100 mmol L^-1，可通过调节自身保护酶系统维持正常代谢平衡。

Abstract:

In order to understand the response of Calendula officinalis seedlings to mixed neutral salt stress, the growth and photosynthetic physiology of seedlings was studied under stressed with NaCl∶Na₂SO₄ at mole ratio of 9∶1. The results showed that the balance of active oxygen metabolism and the integrity of cell membrane structure were maintained by enhancing activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and decreasing content of malondialdehyde (MDA) in leaves of C. officinalis seedlings under lower than 100 mmol L^-1 salt concentration, which could maintain normal photosynthesis and growth of seedlings. When salt concentration was more than 200 mmol L^-1, the activities of SOD, POD and CAT decreased rapidly, and content of MDA increased rapidly, which significant influnced on photosynthetic capacity and growth. Therefore, the threshold salinity of C. officinalis seedlings to mixed neutral salt stress was 100 mmol L^-1, the seedlings could maintain normal metabolic balance by regulating protective enzyme system.