摘要
以干热河谷地区典型乡土树种清香木为试验材料,采用快速植物效率分析仪(PEA),对土壤相对含水量为50%(C_1)、30%(C_2)、20%(C_3)、10%(C_4)、5%(C_5)5种处理下清香木的光系统Ⅱ快速叶绿素荧光诱导动力学参数进行测定,探讨清香木快速叶绿素荧光诱导曲线在不同水分处理下的变化机制。结果表明:(1)清香木经水分胁迫处理后,放氧复合体受到了不同程度的损害,光合电子传递链中Q_A^-大量积累,电子传递能力和量子产额逐渐降低。(2)随着土壤相对含水量的逐渐降低,清香木ABS/CS、TR_o/CS、RC/CS、DI_o/CS均在C_3处理下降到了最低值,而此时ABS/RC、ET_o/RC、DI_o/RC、M_o均达到最大值,V_j在C_2处理下达到了最大值,而此时Ψ_o、ΨE_o、ET_o/CS均降至最低值,ET_o/RC却一直增加。(3)清香木光合性能指数PI_(ABS)对水分胁迫的敏感性比F_v/F_m(φp_o)更强。研究认为,清香木在30%土壤水分处理下已经启动了相应的自我防御机制,质体醌Q_A被还原的速率均减慢,电子在传递过程中受阻;在20%土壤水分处理下天线系统发生了一定程度的降解或者损坏,导致光能的吸收降低,同时将过多的激发能及时散失,减少了活性氧对反应中心造成的伤害;在10%土壤水分处理下,清香木的自我防御机制得以解除,光合作用效率进一步提高。说明清香木的生理状况在水分过多或者过少条件下都会受到明显影响,其健康生长的理论土壤相对含水量应保持在10%左右,清香木能够适应干旱的环境。
We evaluated the change mechanisms of Pistacia weinmannifolia leaves fast chlorophyll under water stress condition,which is typical species in dry and hot valley.The present study was designed to measure fast chlorophyll fluorescence under 5relative soil water contents 50%（C1）,30%（C2）,20%（C3）,10%（C4）and 5%（C5）.The results showed：（1）under the water stress condition,oxygen evolving complex subject of P.weinmannifoliais damaged hardly,and a large number of photosynthetic electron transport chain QA^- are accumulated,electron transfer capability and quantum yield were lower.（2）The minimum and maximum points of ABS/CS,TRo/CS,RC/CS,DIo/CSand ABS/RC,ETo/RC,DIo/RC,Moarrived under C3 level,the minimum and maximum points of VjandΨo,ΨEo,ETo/CSarrived at C2 level,ETo/RC are increased with the relative soil moisture content lower.（3）P.weinmannifolia PIABS（photosynthetic performance index）is more sensitive than Fv/Fm（φpo）.From this reseach,it can be seen that P.weinmannifolia has launched a corresponding self-defense mechanism,plastoquinone QA are slowing the reduced rate,electronic hindered in the transfer process under the C2 level.The antenna system of P.weinmannifolia has been damaged,which leading to reduced absorption of light energy and dissipation of excessive excitation energy in time under the C3 level,and reduce the OEC damage caused by the reaction center,only be lifted at C4,and improve the P.weinmannifoliaphotosynthetic efficiency.Water stress will impact the P.weinmannifoliaphysiological,which will grow health under the relative soil water content keep 10%,the P.weinmannifoliacan adapt the drought conditions.
出处
《西北植物学报》
CAS
CSCD
北大核心
2015年第12期2505-2512,共8页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家自然科学基金(31560237)
