Ameliorating Effects of Calcium Addition on Emergence and Early Seedling Growth of Castor Bean Plants under Saline Conditions

【作者】 周桂生； Shiyuan Lu； Nimir Nimir； Fuyan Zhai；

【Author】 Guisheng Zhou;Shiyuan Lu;Nimir Nimir;Fuyan Zhai;Key Lab of Crop Genetics and Physiology of Jiangsu Province,Yangzhou Univ.;Joint Laboratory of Agricultural Sciences between Department of Agriculture and Agri-Food Canada and Yangzhou University,Yangzhou Univ.;

【机构】 Key Lab of Crop Genetics and Physiology of Jiangsu Province,Yangzhou Univ.； Joint Laboratory of Agricultural Sciences between Department of Agriculture and Agri-Food Canada； Yangzhou University； Yangzhou Univ.；

【摘要】 Salinity is one of the most severe environmental stresses limiting crop production worldwide,especially in regions where soils contain medium to high salinity concentrations.Castor bean（Ricinus communis L.） appears to be tolerant of low to medium saline concentrations.Its production is now being considered in saline soil seashore mudflats where salinity is a threat for conventional crops such as rice（Oryza Sativa L.）,wheat（Triticum aestivum L.）,cotton（Gossypium hirsutum L.）,and rapeseed（Brassica napus L.）.However,the germination and early seedling growth of castor bean are still severely inhibited when the salt concentration in growing media was at or above certain salinity levels.New strategies are,therefore,urgently developed to mitigate these detrimental effects of high salinity on emergence and early seedling growth of castor bean.External application of calcium（Ca） is a possible strategy to mitigating the inhibitory effects of salinity on emergence and seedling establishment of castor bean.A controlled greenhouse study was conducted to assess the interactive effects of soil salinity and Ca addition on the emergence and early seedling growth of castor bean（Ricinus communis L.） in seeding media with a range of molar mass ratios of NaCl to CaCl₂.Seedlings were cultured in organic substrate- conventional soil mixed seeding media containing salts either at 3 or 6 g NaCl kg"1.Supplemental Ca was added at the molar mass ratio of NaCl and CaCl₂ of 20:0,20:1,20:2,and 20:3.Increasing salinity level from 3 to 6 g per kg dry seeding media significantly reduced emergence and seedling growth,with reductions in emergence rate by up to43.7%,plant height by up to 24.7%,and leaf area by 48.8%,.Calcium addition increased emergence by up to68.2%,plant height by up to 18.0%,leaf area by up to 52.5%,and dry plant weight by up to 70.3%,chlorophyll a and chlorophyll（a+b） by up to 87.2%and 51.9%,soluble protein by up to 214.2%,and soluble sugar by 38.2%.Our study indicates that the negative effects of salinity on emergence and early seedling growth of castor bean can be lessened with exogenous application of Ca at appropriate concentrations into saline seeding media.更多还原

【Abstract】 Salinity is one of the most severe environmental stresses limiting crop production worldwide,especially in regions where soils contain medium to high salinity concentrations.Castor bean（Ricinus communis L.） appears to be tolerant of low to medium saline concentrations.Its production is now being considered in saline soil seashore mudflats where salinity is a threat for conventional crops such as rice（Oryza Sativa L.）,wheat（Triticum aestivum L.）,cotton（Gossypium hirsutum L.）,and rapeseed（Brassica napus L.）.However,the germination and early seedling growth of castor bean are still severely inhibited when the salt concentration in growing media was at or above certain salinity levels.New strategies are,therefore,urgently developed to mitigate these detrimental effects of high salinity on emergence and early seedling growth of castor bean.External application of calcium（Ca） is a possible strategy to mitigating the inhibitory effects of salinity on emergence and seedling establishment of castor bean.A controlled greenhouse study was conducted to assess the interactive effects of soil salinity and Ca addition on the emergence and early seedling growth of castor bean（Ricinus communis L.） in seeding media with a range of molar mass ratios of NaCl to CaCl₂.Seedlings were cultured in organic substrate- conventional soil mixed seeding media containing salts either at 3 or 6 g NaCl kg"1.Supplemental Ca was added at the molar mass ratio of NaCl and CaCl₂ of 20:0,20:1,20:2,and 20:3.Increasing salinity level from 3 to 6 g per kg dry seeding media significantly reduced emergence and seedling growth,with reductions in emergence rate by up to43.7%,plant height by up to 24.7%,and leaf area by 48.8%,.Calcium addition increased emergence by up to68.2%,plant height by up to 18.0%,leaf area by up to 52.5%,and dry plant weight by up to 70.3%,chlorophyll a and chlorophyll（a+b） by up to 87.2%and 51.9%,soluble protein by up to 214.2%,and soluble sugar by 38.2%.Our study indicates that the negative effects of salinity on emergence and early seedling growth of castor bean can be lessened with exogenous application of Ca at appropriate concentrations into saline seeding media.更多还原