Cd、Pb、Cr三元胁迫对小麦幼苗生理生化特性的影响

用小麦幼苗做材料,采用溶液培养方法,研究了Cd、Pb、Cr共同胁迫对小麦性状的影响.结果表明,由于Cd、Pb、Cr 3种不同重金属之间互作的存在,三元污染胁迫对叶绿素总量抑制的联合作用和降低渗透势的幅度一直大于单独作用之和;三元污染胁迫下的气孔阻力、可溶性蛋白质含量、MDA含量联合作用一直小于单独作用之和.联合作用随胁迫时间的增加,从小于单独作用之和转变为大于单独作用之和的有叶与根的质膜透性;联合作用从大于单独作用之和转变为小于单独作用之和的有Cd、Pb、Cr三元污染胁迫下的根系活力.对小麦幼苗POD同功酶的影响是:Cd、Pb、Cr三元污染胁迫出现了与单一污染胁迫不同的新酶带,也消失了不同的酶带.该结果可为进一步了解Cd、Pb、Cr污染对小麦的影响机制,为农业生产上早期检查Cd、Pb、Cr对小麦幼苗生长的有害效应和丰富小麦重金属复合污染胁迫研究提供一些理论依据.

Influences of multiple stress by Cd, Pb and Cr on physiological-biochemical characters of wheat seedlings

The coexisting and independent stress effects were studied of three heavy metals of Cd, Pb and Cr on the physiological and biochemical characters of wheat seedlings. The results showed that there were five patterns of joint actions (JA) because of their interactions, comparing with the sum of independent actions (SIA) by three heavy metals. Under exposure to triplicate heavy metal stresses, JAs were always larger than SIAs for the decreases in leaf chlorophyll content and osmotic potential, whereas JAs were smaller than SIAs all the time for leaf stomatal resistance, soluble protein and MDA contents. With the prolongation of stress time, JAs in the solute leakage of roots and leaves presented dramatic changes so that the trend that JAs were smaller than SIAs in early stage was inversely changed in late stage. In contrast, changes in JAs related to SIAs showed the pattern from highness to lowness through the exposure course. POD enzymogram changes were obvious so that triplicate heavy metal stresses induced some new bands and inhibited other bands, compared to individual metal stresses. The findings will serve as a theoretical basis for stress mechanism in crop physiology, and for early monitoring harmful effects of heavy metals in wheat production and deserve to be further explored in the context of pollution ecology.