Effects of Calcium Ion Stress on Leaves of Isatis indigotica
Objective In order to analyze the effects of calcium ion stress on the growth of leaves of Isatis indigotica,the effect of calcium ion stress on leaves of I.indigotica was observed.Methods The seeds of the I.indigotica were grown based on vermicu-lite in small pots with 7cm diameter at the upper mouth and watered with Hoagland nutrient solution under the culture conditions of 25℃,3600 μmol/(m2·s)light intensity and 75％relative humidity.When the plant grows out six leaves,the plants were treated with Hoagland nutrient solution containing calcium ions at different concentrations(0,200,400 mmol/L)and the chan-ges of photosynthetic characteristics and other physiological indexes were observed.Results The results showed that,compared with control group,the net photosynthetic rate(Pn),transpiration rate(Tr),stomatal conductance(Gs),intercellular CO2 con-centration(Ci),and the content of chlorophyll a,chlorophyll b,total chlorophyll and water was decreased gradually under calci-um treatment.The content of total soluble sugar and proline was increased gradually with the increase of calcium ion concentra-tion,while the content of betaine was increased first and then decreased.Water utilization efficiency(WUE),electrolyte leakage rate,malondialdehyde(MDA)content,hydrogen peroxide content and superoxide anion content was increased with the increase of calcium ion concentration.Activity of the superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),ascorbate per-oxidase(APX),monodehydroascorbate reductase(MDHAR),dehydroascorbate reductase(DHAR)and glutathione reductase(GR)was increased with the increase of calcium ion concentration.Conclusion These suggest that calcium stress can inhibit the photosynthetic properties of leaves of Ⅰ.indigotica significantly.It also causes osmotic stress on Ⅰ.indigotica leaves.Ⅰ.indigotica leaves may regulate osmotic pressure by synthesizing osmotic protective substances,and remove reactive oxygen species through antioxidant enzyme system.
Isatis indigoticaLeafCalcium ion stressOsmotic stress
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