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2011年4—10月在山东省林业科学研究院试验苗圃,选取欧美I-107杨扦插苗为试材,采用盆栽控水试验,研究了不同水分处理(正常水分、轻度干旱、中度干旱和重度干旱)对杨树幼苗生长和气体交换、叶绿素荧光特性、活性氧代谢的影响.结果表明:与正常水分处理相比,轻度、中度和重度干旱胁迫下的地径生长量分别下降12.8%、44.5%和65.6%,苗高生长量分别下降12.2%、43.1%和57.2%;随着胁迫强度的增加和胁迫时间的延长,杨树幼苗叶片的PSⅡ光能转化效率、实际量子产量、光化学猝灭系数、净光合速率和气孔导度在轻度胁迫下缓慢下降,而在中度和重度胁迫下迅速下降;非光化学猝灭系数在轻度胁迫下显著升高,而在中度和重度胁迫下先升高后降低;叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性均先升高后降低,但对干旱胁迫和活性氧的响应存在一定差异;叶片相对电导率、丙二醛含量显著增加,质膜受损,大量离子外渗,且重度胁迫下质膜的损害最严重.轻度干旱胁迫下,I-107杨树幼苗具有较高的光合效率和较强的抗氧化保护酶系统;而中度和重度干旱下,其光合效率显著下降,抗氧化保护酶系统明显遭到破坏.
From April to October in 2011, the experiment nursery of Shandong Academy of Forestry, selected the European and American I-107 poplar seedlings as the test material, using the potted water control experiment to study the effects of different water treatments (normal moisture, mild drought, moderate drought And severe drought on the growth, gas exchange, chlorophyll fluorescence and active oxygen metabolism of poplar seedlings.The results showed that compared with normal water treatment, the growth of seedlings under mild, moderate and severe drought stress decreased 12.8%, 44.5% and 65.6% respectively. The growth of seedling height decreased by 12.2%, 43.1% and 57.2% respectively. With the increase of stress intensity and prolongation of stress time, the photosynthetic rate of PSⅡ light energy conversion, the actual quantum yield , The photochemical quenching coefficient, net photosynthesis rate and stomatal conductance decreased slowly under mild stress, but decreased rapidly under moderate and severe stress; the non-photochemical quenching coefficient increased significantly under mild stress, while in moderate (P <0.05) and the activity of CAT (POD) and catalase (CAT) increased firstly and then decreased, but the activities of drought stress and reactive oxygen species There is a certain difference in response; The relative electrical conductivity, malondialdehyde content increased significantly, the plasma membrane damaged, a large number of ions extravasation, and under severe stress the plasma membrane damage is the most serious.With mild drought stress, I-107 poplar seedlings have higher photosynthesis Efficient and strong antioxidant protective enzyme system; while moderate and severe drought, photosynthetic efficiency decreased significantly, the antioxidant protective enzyme system was significantly damaged.