摘要
以4年生曼地亚红豆杉扦插苗为试材,实验前1个月将苗木移栽至花盆中置于大棚内进行正常水分管理。将苗木分为3组,每组10株,3个重复,分别进行干旱胁迫。重度干旱(从试验开始时停止浇水),中度干旱(试验期间3 d浇1次水,浇水量为对照的50%),对照(充足供水)。在重度干旱和中度干旱下分别胁迫35 d,研究曼地亚红豆杉对不同程度干旱胁迫的生理响应,以分析曼地亚红豆杉的抗旱性及抗旱机理。结果表明,水分胁迫下曼地亚红豆杉Pn、E、Gs与对照相比显著下降,Ci在胁迫初期升高,胁迫21 d后下降。水分利用效率(RWUE)先升高后下降,羧化效率(RCE)显著下降。叶绿素a、叶绿素b和总叶绿素含量在胁迫后与对照没有显著差异;Fv/Fm在胁迫期间没有显著变化,而IPI随胁迫强度增加和胁迫时间延长显著下降。推测曼地亚红豆杉在干旱胁迫下叶绿素含量和光系统II(PSII)光能转化能力保持相对稳定,对水分有较高的利用效率,引起光合下降的主要是非气孔因素,即羧化效率的显著下降。在水分胁迫条件下,曼地亚红豆杉SOD活性、POD活性,MDA含量、Pro含量都呈现先升后降的变化,说明曼地亚红豆杉在水分胁迫初期能通过增加保护酶活性来提高对逆境下产生的过氧化物的清除能力,同时增加细胞中游离脯氨酸等渗透调节物质来提高植株的吸水保水能力,维持自身水分平衡,具有较强的抗旱性。
Cuttages of Taxus media cv. hicksii were treated with serious draught and moderate draught for 35 days to study the changes in their photosynthesis andfluorescence parameters under water stress. The results show that the net photosynthesis （Pn）, transpireationcoefficient （E）, stomatal conductance （GS） decreased evidently compared with the contrast. The intercellular CO2 concentration （Ci） at the early stage increased and the decreased 3 weeks after stressed. The water utilization efficiency （RWUE） increased at the early stage andthen decreased, the carboxylation efficiency （RCE） decreased evidently. Chlorophyll a, Chlorophyll b and total chlorophyll content didn＇t change evidently compared with the contrast. And the intrinsic photochemical efficiency （Fv/Fm） didn＇t change evidently during waterstress, but the photosynthesis performance index （IPI） decreased evidently with the water stress increased and the stress time expanded. All the results suggested that the chlorophyll content, the light convert capability of PSII kept relative stabilization, and could use waterwith relatively high efficiency. The main factors that led to the decrease of photosynthesis were the non-stomatal limitations, namely the evident decrease of the carboxylation efficiency. The results also show that all the physiologyical and biochemical indexes increased atthe prophase of water dress, and then decreased. It suggested that Taxus media cv. hicksii had a comparatively high draught resistance. It could increase the eliminate ability of peroxides by increasing the activity of SOD and POD. It also could increase the ability of watersucking and keeping by increasing the contents of Pro.
出处
《中南林业科技大学学报》
CAS
CSCD
北大核心
2012年第12期147-153,共7页
Journal of Central South University of Forestry & Technology
基金
四川省教育厅重点研究项目"曼地亚红豆杉水分
光照
温度胁迫生理响应研究"(2006B014)
关键词
曼地亚红豆杉
水分胁迫
生理响应
叶绿素荧光
Taxus media cv. hicksii
water stress
physiology response
chlorophyll fluorescence
