镉胁迫对二穗短柄草幼苗叶片中无机离子稳态的影响

Responses of Inorganic Ions Homestasis in Brachypodium distachyonSeedling under Cd Stress

为探讨镉胁迫下二穗短柄草（Brachypodium distachyon）叶片对各无机离子的吸收及离子间的平衡机制,测定0~300μmol·L-1 CdSO4溶液胁迫下二穗短柄草叶片中主要无机离子含量的变化。结果表明,随着镉胁迫程度的加剧,二穗短柄草叶片中出现＂吸钠排钾＂现象,即Na^＋和K^＋含量分别增加和下降;Ca^2＋、S2-、Cd^2＋含量逐渐增加,而Mg^2＋、Si^ 4＋含量逐渐降低。叶绿素a、叶绿素b、叶绿素a＋b含量在低浓度镉胁迫时虽有升高趋势,但随着处理浓度的逐渐增加而缓慢降低,叶片含水量也随之逐渐下降。说明二穗短柄草幼苗叶片无机离子吸收和平衡、光合色素合成、含水量均不同程度受到镉胁迫的影响,但植株能通过体内不同无机离子含量的变化来缓解镉胁迫危害,从而提高对其的耐受能力。

To investigate the effect of Cd stress on growth and inorganic ions of Brachypodium dis- tachyon （Bd21）, we treated Bd21 seedlings with various concentration of CdSO4 （0,50,100,150,200 and 300 μmol . L^-1）. Then examined their Chlorophyll and main Inorganic ions contents in the leaves. The result showed that with the CdSO4 concentration increasing, the seedling of Bd21＇s Na＋ content was increase, K^＋ content was reduced, so it appeared the ＂uptake Na prevent K＂ Cd resistance characteristics. Ca^2＋ content participate in content were creased. The resistance in th decrease in the growth and Ch was also increased under Cd stress, it mainly induced to accumulate and e seedlings Cd stress. Along with the Cd stress increase, Mg^2＋ and Si^4＋ leaves, but S2- was increase. The accumulation of Cd itself was in- lorophyll （chla, chlb, chlaq-b） content of Bd21 seedlings were signifi- cantly inhibited by Cd stress. As compared with control, when Cd concentration reached 50 μmol . L^-1 , the Chlorophyll were more than control, but dropped after 100 μmol. L^-1, at the same time, changes of water contents were decrease. These different inorganic ions contents mutually benefit each other and cooperate to promote their resistance to Cd stress.