水杨酸和热锻炼诱导的高羊茅幼苗的耐热性与抗氧化的关系

Thermotolerance Related to Antioxidation Induced by Salicylic Acid and Heat Hardening in Tall Fescue Seedlings

研究了水杨酸 (SA)处理和热锻炼 (HH)对高羊茅 (FestucaarundinaceaSchreb .)幼苗耐热性的影响和在耐热性诱导过程中植物体内可溶性蛋白含量与超氧化物歧化酶 (SOD)、过氧化物酶 (POD)和过氧化氢酶(CAT)等 3种抗氧化酶的活性变化。结果表明 :0 .5mmol/L的SA预处理能显著提高高羊茅幼苗在 4 2℃热胁迫 (HS)后转至常温下恢复生长 18d时的苗高、绿叶数和绿叶指数 ;在常温下SA提高高羊茅幼苗的CAT活性 ,降低POD活性 ,而对SOD的影响不显著 ;SA和HH均能降低高羊茅幼苗在HS下细胞外渗液电导率 ,提高可溶性蛋白的含量和SOD、CAT活性 ,但不能显著提高POD活性。因此 。

The influence of salicylic acid (SA) and heat hardening (HH) on heat tolerance and the parallel changes in soluble protein content and the activities of 3 antioxidant enzymes, ie superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), were studied in tall fescue ( Festuca arundinacea Schreb.) seedlings. Results from the tests showed that SA 0.5 mmol/L significantly increased the seedling height, green leaf number per plant and green leaf index of the plants treated under 42℃ for 16 h followed by a 18 d recovery under 25℃ (Table1, Fig.1). SA significantly increased CAT (Figs.6, 7) ,but decreased POD (Fig.5), and do not affect SOD (Fig.4) activities in tall fescue seedlings at 25℃ (HS 0 h). Both SA and HH could alleviate the cellular electrolytic leakage (Fig.2) and increase the soluble protein content (Fig.3) and SOD (Fig.4) and CAT (Fig.7) activities but could not raise POD (Fig.5) activity significantly in the seedlings under heat stress (HS). It suggests that SA or HH enhances thermoprotection by similar mechanisms.