Chin J Plant Ecol ›› 2012, Vol. 36 ›› Issue (10): 1082-1094.DOI: 10.3724/SP.J.1258.2012.01082

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Effects of Zn treatment on physiological characteristics, photosynthesis, ultrastructure of root tip cell and grain Zn accumulation in different varieties of rape

LIU Jun, CHEN Gui-Qing, XU Wei-Hong*(), HAN Gui-Qi, ZHANG Hai-Bo, WANG Hui-Xian, ZHANG Ming- Zhong   

  1. College of Resources and Environment, Southwest University, Chongqing 400715, China
  • Received:2012-02-15 Accepted:2012-06-05 Online:2012-02-15 Published:2012-09-26
  • Contact: XU Wei-Hong

Abstract:

Aims Our objectives were to reveal differences in physiological characteristics, photosynthesis, ultrastructure of root tip cell and grain Zinc (Zn) accumulation in different varieties of rape under different Zn treatments.
Methods Pot experiments were carried out. Zn treatments were 0, 1.0, 5.0, 10.0 and 20.0 mg·kg -1, and five varieties of rape were ‘Luopingjincaizi’ (Brassica juncea), ‘Erniuwei’ (B. juncea), ‘Liyangkucai’ (B. juncea), ‘Nantonghuangyoucai’ (B. chinensis) and ‘H33’ (B. napus). All experiments were performed in triplicate, and pots were arranged in a completely randomized design inside a greenhouse.
Important findings The dry weights of roots, leaf, straw, grain and plant, physiological characteristics and concentration and accumulation of Zn significantly differed among the different varieties and Zn treatments. The activities of antioxidant enzymes, net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), and dry weights of plant, straw, leaf and grain increased at Zn ≤ 5.0 mg·kg -1. The highest yields of grain for the five varieties were all observed in the 5.0 mg·kg -1 Zn treatment and were 37.7%, 23.4%, 29.5%, 82.6% and 18.0% greater than the control, respectively. Ultrastructural damage was found in the root-tip cells for ‘Luopingjincaizi’, ‘Erniuwei’, ‘Nantonghuangyoucai’ and ‘Liyangkucai’ in the presence of 20.0 mg·kg -1 Zn and included mitochondria inflation, cell-wall thickening, nucleus atrophy and decreased contents of nucleus, while unaltered structure of the root-tip cells was observed in ‘H33’. Grain Zn accumulation for the five varieties increased at Zn ≤ 5.0 mg·kg -1, and decreased at Zn > 5.0 mg·kg -1. Highest concentration and accumulation of Zn in grains were observed in ‘Erniuwei’ at 5.0 and 10.0 mg·kg -1 Zn (172.34 mg·kg -1, 2.932 mg·pot -1 and 164.10 mg·kg -1, 2.575 mg·pot -1) treatment, respectively.

Key words: grain Zn accumulation, physiological characteristic, rape (Brassica), ultrastructure of root tip cell