镉胁迫对吊兰及银边吊兰生长及镉富集特性的影响

Effects of cadmium stress on growth and cadmium enrichment of Chlorophytum comosum and Chlorophytum comosum var. variegatum

选择吊兰和银边吊兰为试验材料,采用水培法研究其在不同Cd^(2+)处理浓度(0、20、80、200μmol·L^(-1))下生长及生理特性的变化。结果表明:20μmol·L^(-1)镉对两种吊兰的影响较小,单叶面积、总叶面积、叶绿素(Chl)a含量、总叶绿素[Chl (a+b)]含量、类胡萝卜素含量、Chl a/Chl b值、胞间二氧化碳浓度(Ci)和蒸腾速率(Tr)与对照(CK)基本无显著差异;80μmol·L^(-1)镉胁迫下两种吊兰叶片初始荧光(F_(o))和非光化学淬灭系数(NPQ)升至最高水平;200μmol·L^(-1)镉胁迫下,两种吊兰生物量、叶绿素含量、最大净光合速率(P_(n))、气孔导度(g_(s))、最大光化学量子产量(F_(v)/F_(m))、实际光化学量子产量Y_((II))、转移系数(TF)以及各部分生物量均降至最低水平,而两种吊兰的过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)及过氧化氢酶(CAT)活性和银边吊兰的丙二醛(MDA)含量均有不同程度的增加。随着镉处理浓度的增加,两种吊兰各器官Cd含量持续升高,且主要富集在根部;吊兰各器官Cd含量及富集系数(BCF)在胁迫处理下均高于银边吊兰。研究表明,两种吊兰对镉具有一定的耐性,其中吊兰对Cd的耐受能力强于银边吊兰,可考虑作为绿化植物用于修复镉污染水体或土壤。

We examined the growth and physiological characteristics of Chlorophytum comosum and Chlorophytum comosum var. variegatum by hydroponics at different Cd^(2+) concentrations(0, 20, 80, 200 μmol·L^(-1)). The results showed that 20 μmol·L^(-1) Cd^(2+) did not affect those two varieties, with no changes of single leaf area, total leaf area, chlorophyll(Chl) a content, Chl(a+b) content, carotenoid content, Chla/Chlb value, intercellular carbon dioxide concentration(Ci) and transpiration rate(Tr) compared with the control(CK). Under the 80 μmol·L^(-1) Cd^(2+) stress, the initial fluorescence(F_(o)) and non-photochemical quenching coefficient(NPQ) were the highest for both varieties. As for Cd^(2+) at 200 μmol·L^(-1), the biomass, chlorophyll content, maximum net photosynthetic rate(P_(n)), stomatal conductance(g_(s)), maximum photochemical quantum yield(F_(v)/F_(m)), actual photochemical quantum yield Y_((II)), the transfer factor(TF) of both varieties and all parts biomass decreased to the lowest, while peroxidase(POD), ascorbic acid peroxidase(APX) and catalase(CAT) activities of two varieties and MDA content of C. comosum var. variegatum increased in different degrees. With the increases of Cd^(2+) stress, the Cd content in organs of two varieties showed an increasing trend, with higher Cd accumulation in roots. C. comosum had higher Cd content and bioconcentration factor(BCF) in all organs than C. comosum var. variegatum. It suggested that two varieties had the ability to resist Cd stress. The tolerance of C. comosum was stronger, and thus could be considered as a green plant to remediate Cd contaminated water or soil.