Abstract

The stress-buffering effects of cotyledonary leaves of Ricinus communis and the protection thus offered to the true leaves upon exposure to copper stress was performed by analyzing bioaccumulation of Cu and associated metabolic processes in the presence and absence of cotyledonary leaves. One-month-old seedlings of R. communis were treated with various concentrations of CuSO₄ for 6 d under hydroponics with quarter strength modified Hoagland medium. Even though the photosynthetic pigments showed a decreasing trend with an increase in CuSO₄ concentration and days of exposure in cotyledonary and true leaves, it was significant in true leaves with excised cotyledonary leaves. The results of chlorophyll a fluorescence parameters indicated that toxic levels of CuSO₄ do not impart any major negative effect on the photochemistry of true leaves along with cotyledonary leaves. The analysis of osmolality, malondialdehyde, and metabolites showed a significantly increasing trend in true leaves with excised cotyledonary leaves. The above observations were strongly supported by higher Cu bioaccumulation in true leaves with excised cotyledonary leaves. The results suggest that the cotyledonary leaves have got the potential to evade Cu toxicity and thereby R. communis can be effectively used for the phytoremediation of Cu contaminated lands.

抽象的

通过分析在存在和不存在子叶的情况下铜的生物富集和相关的代谢过程，来进行蓖麻子叶的应力缓冲作用以及在暴露于铜胁迫下对真叶的保护作用。在四分之一强度改良的Hoagland培养基中，在水培条件下，用不同浓度的CuSO ₄处理1个月大的Comm。R. communis幼苗。即使光合色素在子叶和真叶中随CuSO ₄浓度的增加和暴露天数的增加而显示出下降的趋势，但在切去子叶的真叶中却是显着的。叶绿素a的结果荧光参数表明，CuSO _4的毒性水平不会对真叶和子叶叶片的光化学产生任何重大的负面影响。对渗透压，丙二醛和代谢产物的分析显示，带有切去的子叶的真叶具有显着增加的趋势。上述观察结果得到切去子叶的真叶中较高的铜生物积累的强烈支持。结果表明，子叶具有逃避铜毒的潜力，从而可以有效地利用普通R. communis对铜污染的土地进行植物修复。