title: Protective effect of chitosan on photosynthesis and antioxidative defense system in edible rape (Brassica rapa L.) in the presence of cadmium.
abstract: Chitosan (CTS) induces plant tolerance against several abiotic stresses, including salinity and drought exposure. However, the role of CTS in cadmium (Cd)-induced stress amelioration is largely unknown. In the present study, a hydroponic pot experiment was conducted to study the roles of CTS with different molecular weight (Mw) (10kDa，5kDa and 1kDa) in alleviating Cd toxicity in edible rape (Brassica rapa L .). The results showed that Cd stress significantly decreased plant growth, leaf chlorophyll contents and increased the malondialdehyde (MDA) level in rape leaves. Foliar application of CTS promoted the plant growth and leaf chlorophyll contents, and decreased the malondialdehyde (MDA) level in edible rape leaves under Cd stress. The alleviation effect of CTS on toxicity was depended on its Mw and CTS with Mw of 1kDa showed the best activity. Spraying 1kDa CTS onto the leaves of edible rape under Cd-toxicity could decrease shoot Cd2+concentration and improve photosynthetic characteristics of edible rape. Moreover, 1kDa CTS also significantly enhanced non-enzymatic antioxidants (ascorbic acid) and enzyme activities (superoxide dismutase, catalase and guaiacol peroxidase) under Cd stress. Based on these findings, it can be concluded that application of exogenous CTS could be an effective approach to alleviate the harmful effects of Cd stress and could be explored in an agricultural production system.
authors.affiliation: Key Laboratory Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China. Electronic address: u571zhy@126.com.
authors.forename: Haiying
authors.initials: H
authors.lastname: Zong
authors.affiliation: Key Laboratory Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China. Electronic address: sliu@qdio.ac.cn.
authors.forename: Song
authors.initials: S
authors.lastname: Liu
authors.affiliation: Key Laboratory Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China. Electronic address: xingronge@qdio.ac.cn.
authors.forename: Ronge
authors.initials: R
authors.lastname: Xing
authors.affiliation: Key Laboratory Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China. Electronic address: chenxl@qdio.ac.cn.
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Chen
authors.affiliation: Key Laboratory Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China. Electronic address: pcli@qdio.ac.cn.
authors.forename: Pengcheng
authors.initials: P
authors.lastname: Li
mesh_terms: D001205:Ascorbic Acid / Q000378:metabolism; D029741:Brassica rapa / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D002104:Cadmium / Q000032:analysis / Q000494:pharmacology*; D002374:Catalase / Q000378:metabolism; D048271:Chitosan / Q000737:chemistry / Q000494:pharmacology*; D002734:Chlorophyll / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D008970:Molecular Weight; D009195:Peroxidase / Q000378:metabolism; D010788:Photosynthesis / Q000187:drug effects*; D018515:Plant Leaves / Q000378:metabolism; D018520:Plant Shoots / Q000737:chemistry; D065840:Protective Factors; D013312:Stress, Physiological / Q000187:drug effects; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D002104:Cadmium; D002734:Chlorophyll; D008315:Malondialdehyde; D048271:Chitosan; C121048:guaiacol peroxidase; D002374:Catalase; D009195:Peroxidase; D013482:Superoxide Dismutase; D001205:Ascorbic Acid
keywords: Antioxidant defense system; Cd; Chitosan; Edible Rape (Brassica rapa L .); Photosynthetic characteristics