NaCl胁迫下外源钙对芦苇种子萌发的影响

Effects of Exogenous Calcium on the Seed Germination in Phragmites australis under NaCl Stress

以黄河三角洲湿地广泛分布的芦苇种子为试材,采用不同浓度Na Cl(0,50,100,150,200,300 mmol/L)和Ca Cl2(0,5,10,20,40 mmol/L)来分别模拟盐胁迫和外源钙,研究了盐胁迫、外源钙及两者交互作用对芦苇种子萌发的影响。结果表明:随着Na Cl浓度的增加,各处理间种子发芽率、发芽势、发芽指数和活力指数均与对照呈显著递减趋势,而相对盐害率呈上升趋势;单一Ca Cl2处理下,中低浓度(<20 mmol/L)的外源钙对芦苇种子萌发无显著影响,而高浓度的外源钙(40 mmol/L)对种子萌发具有抑制作用;盐胁迫条件下,芦苇种子发芽率、发芽势、发芽指数及活力指数均随外源钙浓度的增加呈先升高后降低的趋势,相对盐害率呈相反趋势,其中以Ca Cl2浓度为10 mmol/L时缓解效果最佳,而当Ca Cl2浓度在20 mmol/L时,芦苇种子发芽率、发芽势、发芽指数及活力指数呈下降趋势,到40 mmol/L时降到最低值,此时相对盐害率达到最大值,盐害加深,而此后随着盐胁迫的加剧,下降趋势更明显。综上所述,在潮上带盐碱化湿地恢复中,外源施用一定浓度的Ca Cl2,其中以10 mmol/L浓度为宜,可以有效促进芦苇在盐碱条件下的萌发。

The effects of different salt stress and exogenous Ca2+and their interactions on the seed germination characteristics of Phragmites australis which is widespread in the Yellow River Delta wetland were studied here.Salt stress and exogenous Ca2+were respectively simulated using different concentrations of Na Cl( 0,50,100,150,200,300 mmol/L) and Ca Cl2( 0,5,10,20,40 mmol/L). The results showed that the seed germination rate,germination potential,germination index and vigor index among treatments significantly decreased and the relative salt harm rate increased compared to the control with the increased of Na Cl stress. Under exogenous Ca Cl2 treatments,the medium or low concentrations of exogenous Ca2+( < 20 mmol/L) had lesser effects on the seed germination parameters in Phragmites australis,whereas the higher concentrations of exogenous Ca2+( 40 mmol/L) had inhibition effect on the seed germination. The four germination indexes in Phragmites australis under Na Cl stress increased at first and then decreased with the increased of exogenous Ca2+,but the relative salt harm rate showed the opposite tendency and 10 mmol/L Ca2+was the most effective concentrations in alleviating Na Cl stress. The four germination indexes decreased when the concentrations of exogenous Ca2+was 20 mmol/L,and it decreased to the minimum when the concentrations of exogenous Ca2+was 40 mmol/L,while the relative salt harm rate achieved the maximum at the same time,and then the trend of the decrease was obvious with the increase of Na Cl stress. In summary,in the restoration of salt-alkalization wetland in the supratidal zone,the seed of Phragmites australis could be presoakedin the Ca Cl2 solution at concentration of 10 mmol/L in order to improve the rate of seedling.