干旱胁迫对丹参幼苗气体交换特征和保护酶活性的影响

EFFECTS OF DROUGHT STRESS ON GAS EXCHANGE CHARACTERISTICS AND PROTECTIVE ENZYME ACTIVITIES IN TWO VARIETIES OF Salvia miltiorrhiza Bge. SEEDLINGS

以大叶型丹参(SA)和小叶型丹参(SI)为材料,设置了对照正常供水(CK)、轻度干旱胁迫(LD)、中度干旱胁迫(MD)、重度干旱胁迫(SD)4个处理,研究了不同程度干旱胁迫对丹参叶片气体交换特征与保护酶的影响。结果显示:(1)干旱胁迫下2个丹参品种叶片的净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)都有不同程度下降。中度和重度干旱胁迫对SA的Pn影响明显大于SI。(2)干旱胁迫下,2个品种的瞬时水分利用效率(WUE)呈先上升后下降的趋势,SI的WUE高于其相应对照,3个干旱处理下分别是SA的1.2、2.27、2.17倍。(3)轻度干旱胁迫下,2个品种叶绿素(Chl a,Chl b和Chl a+b)含量均升高,中度和重度胁迫下下降。(4)随着干旱胁迫程度的增加,2个品种的电解质渗漏率和丙二醛含量上升,而SI增加的幅度小于SA;轻度胁迫下,过氧化氢酶(CAT)、抗坏血酸氧化酶(APX)、超氧化物岐化酶(SOD)、过氧化物酶(POD)的活性均升高,而在中度和重度胁迫时有所下降,但在中度胁迫时SI的CAT和APX活性分别高出其对照5.92%和8.07%。结果表明小叶型丹参具有更强的干旱适应能力。

Taking the seedlings of Salvia miltiorrhiza cv.sativa（SA） and S.miltiorrhiza cv.silcestris（SI） as test materials,a pot-cultivation experiment was conducted to investigate effects of drought stress on gas exchange parameters and protective enzyme activities under drought stress.Four treatments were designed by controlled irrigation： control（CK）,light drought（LD）,moderate drought（MD）,and severe drought（SD）.The results showed：（1） The net photosynthetic rate（Pn）,stomatal conductance（Gs）,transpiration rate（Tr） of two varieties all decreased gradually under drought stress,and drought stress had more obvious effects on the Pn of SA than of SI.（2） The instantaneous water use efficiency（WUE） of two varieties increased first and then decreased during drought stress,however,WUE of SI was higher than CK with 1.2,2.27,2.17 times higher than those of SA under LD,MD,SD respectively.（3） The contents of chlorophyll（Chl a,Chl b,Chl a ＋ b） increased under LD,and decreased under MD and SD.（4） With aggravating of the drought stress,the electrolyte leakage（EL） and content of malonyldialdehyde（MDA） in leaves of two varieties increased,while,those of SI decreased more slowly than SA.The activity of protective enzyme including catalase（CAT）,peroxidese（APX）,superoxide dismutase（SOD）,and peroxidase（POD） in two varieties all increased under LD,and then decreased under MD and SD,but under MD,the activities of CAT and APX of SI were 5.92% and 8.07% higher than those of CK.These results suggested that SI has a higher drought resistant adaptability than SA.