高温锻炼对干旱胁迫下南方红豆杉生长和生理生化指标的影响

Effects of High Temperature Exercise on Growth and Physiological and Biochemical Characters of Taxus wallichiana var.mairei under Drought Stress

为给干旱半干旱地区高效种植南方红豆杉提供理论依据,本试验以5年生南方红豆杉为材料,设置40、45、50℃高温锻炼8 h后再恢复至25℃培养的处理组和一直处于25℃培养的对照(CK),之后对这4个处理同时进行干旱胁迫,研究其对南方红豆杉生物量、根冠比和叶片含水量、相对含水量、光合色素含量(叶绿素a、叶绿素b、类胡萝卜素和叶绿素总含量)、丙二醛(MDA)含量及叶片过氧化物酶(POD)、过氧化氢酶(CAT)活性的影响。结果表明,与CK相比,干旱胁迫21天时,40、45℃处理南方红豆杉的叶片含水量、相对含水量及生物量随着温度的上升呈现不断下降的趋势,根冠比则不断增大。干旱胁迫21天时,40℃和45℃高温处理南方红豆杉叶片光合色素含量、POD活性显著高于CK和50℃处理,MDA含量显著低于CK;整个干旱胁迫过程中,两处理的CAT活性呈现干旱胁迫前期高后期低的现象;40℃处理南方红豆杉叶片POD活性最高,其叶片含水量、叶片相对含水量、根冠比、生物量与CK相比差异不显著。综之,南方红豆杉存在温度和干旱交叉适应现象,适宜高温锻炼后的南方红豆杉比未经高温锻炼的更能适应干旱半干旱环境。

In order to provide theoretical references for efficient cultivation of Taxus wallichiana var.mairei in arid and semi-arid areas,5-year-old T.wallichiana var.mairei plants were firstly treated under 40,45 and 50℃for 8 h respectively and then cultured at 25℃with those cultured at 25℃all the time as control(CK),then they were subjected to drought stress at the same time.The biomass,root to shoot ratio,leaf water content,relative water content,photosynthetic pigments contents(chlorophyll a,chlorophyll b,carotenoid and total chlorophyll contents),malondialdehyde(MDA)content and leaf peroxidase(POD)and catalase(CAT)activities of T.wallichiana var.mairei were measured.The results were as follows.Compared with CK,the leaf water content,relative water content and biomass of plants treated under 40℃and 45℃decreased with the increase of temperature,while the root-shoot ratio increased.After 21 days of drought stress,the pho-tosynthetic pigments contents and POD activity of leaves under 40℃and 45℃treatments were significantly higher compared with CK and 50℃treatment,and the MDA content was significantly lower than that of CK.During the whole process of drought stress,CAT activity under 40℃and 45℃treatments showed higher at the early stage and lower at the later stage.The POD activity of leaves was the highest under 40℃treatment,and the leaf water content,leaf relative water content,root to shoot ratio and biomass were not significantly different from CK.In summary,there was cross adaptation between temperature and drought in T.wallichiana var.mairei,and the plants after suitable high-temperature exercise were more adaptable to arid and semi-arid environments than those without high-temperature exercise.