Chinese Journal of Agrometeorology ›› 2018, Vol. 39 ›› Issue (12): 805-813.doi: 10.3969/j.issn.1000-6362.2018.12.005

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Effects of Low Temperature on Physiological Characteristics of Rice Seedlings with Different Cold Tolerance and Anatomical Structure of Root Tip

WU Li-qun, CAI Zhi-huan, ZHANG Gui-lian, LIU Yi-tong, ZHAO Rui   

  1. 1.College of Agronomy, Hunan Agricultural University, Changsha 410128, China; 2.Southern Regional Collaborative Innovation Center for Grain and Oil Crop, Changsha 410128; 3.Hunan Provincial Key Laboratory of Rice and Rapseed Breeding for Disease Resistance, Hunan Agricultural University, Changsha 410128
  • Online:2018-12-20 Published:2018-12-11

Abstract: In order to explore the influence mechanism of low temperature on rice seedlings, a hydroponics experiment was conducted using 2 rice varieties with different cold tolerance at seedling stage including the cold-tolerant cultivar Sanqishiluo and cold sensitive cultivar Xiangzaoxian45, cultivated in light incubator under two different temperature treatments, the two temperature treatments were optimal temperature treatment (25℃,taken as control,CK) and low temperature treatment(10℃), respectively. The effects of low temperature on the physiological characteristics of rice seedlings and anatomical structure of root apex were studied. The results showed that compared with the control, total root number, longest root length, root fresh weight, root dry weight, root total absorption area, root active absorption area,and root activity decreased under low temperature treatment, and the decrease extent was increased with the increase of treatment time, the reduced range of cold-sensitive cultivar Xiangzaoxian45 was greater than that of cold-tolerant cultivar Sanqishiluo. The activity of SOD and POD increased first and then decreased, and relative conductivity and MDA content increased. The change range of SOD activity, POD activity, relative conductivity and MDA content in cold-tolerant cultivar Sanqishiluo was less than that of cold sensitive cultivar Xiangzaoxian45. The contents of free amino acids and soluble sugar in root increased first and then decreased under low temperature, the change range of cold-tolerant cultivar Sanqishiluo was higher than that of cold sensitive cultivar Xiangzaoxian45. Under low temperature, epidern cell of root tip wall in cold-sensitive cultivar Xiangzaoxian45 arranged irregularly and untightly, vascular bundle of connective tissue was seriously destroyed, and vascular bundle sheath cell arranged irregularly, xylem and phloem were unclear. While epidern cell of root tip wall in vascular bundle of connective tissue in cold-tolerant cultivar Sanqishiluo arranged regularly and tightly, vascular bundle sheath cell and parenchyma cells arranged regularly, xylem and phloem were clear. Results showed that the different physiological and morphological changes were inspired and induced by low temperature, and by applying physiological and morphologica changes to reply synthetically the influence of low temperature on rice seedlings.

Key words: Rice, Low temperature, Seedling, Physiological characteristics, Anatomical structure of root tip