马尾松不同叶型幼苗对干旱及复水的生长及生理响应

摘要

To understand the responses of seedlings with different leaf shapes to drought stress and re-watering, we studied the one-year seedlings of Pinus massoniana in common garden simulating soil drought condition.We compared the growing rate, photosynthetic pigments contents, osmotic adjustment substances contents, MDA molality and protective enzyme ac-tivities by drought stress (last for 0, 7, 14, 21 and 28 d, respectively) and re-watering (at the 14, 21 and 28 d after drought stress treated) treatments.Drought resistance of the three types of seedlings was evaluated by membership function method.The contents of chlorophyll and carotenoid dropped when the drought stress was going on.While the free proline, MDA molality, soluble sugar and soluble protein contents increased, significantly higher than the control check ( CK) .The SOD and POD activities increased under the drought treatments and reached on the peak in the moderate drought dress, and then decreased.The growth rates of protective enzymes activities were different on the seedlings indicating variations on capability to elimination of peroxide.The responses to the drought and re-watering showed differences on the levels of drought dress.With the membership function method, the list of drought resistance from high to low for the three types of seedlings was typeⅠ, typeⅢand typeⅡunder the slight drought.That ranked in descending order as typeⅡ, typeⅠand typeⅢunder the moderate drought, as that for typeⅢ, typeⅡand type Ⅰunder the heavy drought dress.%为了探讨马尾松不同叶型幼苗对持续干旱胁迫及复水处理的适应能力,采用温室盆栽方法模拟土壤干旱条件,分别对干旱胁迫0、7、14、21、28 d及胁迫14、21、28 d复水后幼苗生长速率、叶片中光合色素质量分数、渗透调节物质质量分数、MDA质量摩尔浓度及保护酶活性的变化进行分析,并采用模糊数学隶属函数法对3种叶型幼苗抗旱性进行综合评价,以期为马尾松苗木质量评价及干旱立地造林幼苗的选用提供理论支撑.结果表明:随着干旱胁迫持续进行,3种叶型幼苗生长所受抑制程度不同;叶绿素、类胡萝卜素质量分数显著下降;游离脯氨酸、MDA质量摩尔浓度、可溶性糖和可溶性蛋白质量分数均呈现升高趋势,显著高于对照,其中游离脯氨酸质量分数增幅最大;SOD、POD活性呈先升后降变化,在中度干旱胁迫(21 d)时均达到最高,但3种叶型幼苗保护酶活性增幅不同,表现出不同的清除过氧化物能力;随着干旱胁迫的持续,幼苗复水后各指标恢复能力各异.通过隶属函数法分析得出:3种叶型幼苗对不同干旱处理的主动响应及适应能力不同,在轻度干旱胁迫下,幼苗抗旱性由强到弱的顺序为Ⅰ类型、Ⅲ类型、Ⅱ类型;中度干旱胁迫下,幼苗抗旱性由强到弱的顺序为Ⅱ类型、Ⅰ类型、Ⅲ类型;重度干旱胁迫条件下,幼苗抗旱性由强到弱的顺序为Ⅲ类型、Ⅱ类型、Ⅰ类型.