Abstract
Aluminum (Al) stress has strong negative effects on growth, development and yield formation in crops. However, few studies focused on aluminum stress in sweet corn seedlings. In the present study, 18 sweet corn varieties were used to analyze the morphological and physiological changes of sweet corn seedlings in response to Al-induced stress. Results have shown that treatment by AlCl3, significantly affected root elongation, chlorophyll content, plant height, fresh weight, superoxide dismutase (SOD) activity, peroxidase (POD) activity, catalase (CAT) activity and Al content in root tips in sweet corn, according to the significant interaction by variety × AlCl3 treatment except for CAT. Al-induced stress inhibited root length in all sweet corn varieties, and it resulted in a decrease in chlorophyll content, plant height, fresh weight, and SOD activity in most of the sweet corn varieties. The treatment by AlCl3 increased in POD activity except for GLT31; however, the intensity of these effects varied among varieties. In addition, the correlation between morphological and physiological characteristics showed that Al content in root tips was negatively correlated with relative root growth (RRG) and chlorophyll content at a significant level of 0.01, and it was negatively correlated with CAT activity at the significant level of 0.05. There were significant positive correlations between plant height and fresh weight at a significant level of 0.01, and chlorophyll content was positively correlated with RRG and CAT at the significant level of 0.05. The principal component analysis showed that plant height, RRG, SOD activity, fresh weight, Al content of root tips and fresh weight were the main morphological and physiological characteristics in sweet corn seedlings affected by AlCl3 treatment. In addition, we found that HWT2, HWT1 and HZ388 were the high-tolerant varieties to Al treatment.
Highlights
Human industrial and agricultural production activities have accelerated soil acidification, and it has been estimated that approximately 50% of the world’s arable land is acidic (Ryan & Delhaize, 2010; Kochian, 1995)
Eighteen sweet corn varieties widely planted in South China were used in this study, including Guangtian No.8 (GT8), Jinbaitian No.10 (JBT10), Huanong No.168 (HN168), Huajintian No.1 (HJT1), Huanong No.3 (HN3), Huaweitian No.2 (HWT2), Meizhentian No.1 (MZT1), Huaweitian No.1 (HWT1), Litian No.8 (LT8), Guangliangtian No.31 (GLT31), Zhongtian No.8 (ZT8), Zhuyutian No.1 (ZYT1), Jinguangxi (JGX), Yuetian No.30 (YT30), Huazhen No.388 (HZ388), Huangcai No.11 (HC11), Guangtian No.18 (GT18), and Hantian No.309 (HT309)
Once Al-induced toxicity stress occurs in acidic soil, plant root elongation is inhibited at first, and the absorption of water and mineral nutrient elements is disrupted eventually resulting in the decrease of crop quality and yield (Kochian, 1995)
Summary
Human industrial and agricultural production activities have accelerated soil acidification, and it has been estimated that approximately 50% of the world’s arable land is acidic (Ryan & Delhaize, 2010; Kochian, 1995). Aluminum (Al) is the most abundant metal element in the earth’s crust, but its toxicity to higher plants depends on soil pH value (Bojórquez-Quintal et al, 2017). Soil acidification can activate the transformation of Al minerals, promoting the change of bound Al to the ionic state. These forms of Al are available for higher plants in soil and exhibit phytotoxicity (Ulrich & Panbrath, 1983; MacDonald & Martin, 1998). Previous studies have shown that the root elongation is inhibited and the growth of above-ground parts is hindered under the Al toxicity stress, resulting in decreased biomass of the whole plant (Rengel, 1992; Kollmeier et al, 2000). Al stress can reduce the chlorophyll content and inhibit the activities of enzymes involved in jas.ccsenet.org
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