草决明生长发育对盐胁迫的响应及耐盐性评价

Response of Growth and Development of Cassia Obtusifolia to Salt Stress and Evaluation of Salt Tolerance

为了探讨草决明生长发育对盐胁迫的响应并确定其耐盐鉴定指标,采用梯度滨海盐渍土鉴定法,研究了不同盐胁迫[土壤含盐量0.1%(CK)、0.2%、0.3%、0.4%、0.5%、0.6%、0.7%、0.8%和0.9%]对草决明株高、主根长、地上部分生物量、地下部分生物量、产量和百粒重的影响,并对草决明主要生长指标与土壤含盐量的相关性进行了分析。结果表明:≥0.3%的盐分胁迫会显著抑制草决明的生长速率,而0.2%的低盐胁迫在短期(30 d)内可以刺激草决明的株高生长、在胁迫时间较长(超过30 d)时也会对草决明的株高生长产生明显的抑制效应,但0.2%~0.3%盐分胁迫下草决明的地上部分生物量较CK显著增加;0.2%~0.9%盐分胁迫下,草决明的主根长均与CK无显著差异;0.4%盐分胁迫下,草决明产量达到最高,但与CK差异不显著;≥0.5%盐分胁迫下草决明的地上及地下部分鲜重均较CK显著下降,其中≥0.6%盐分胁迫下株高显著降低,≥0.8%盐分胁迫下草决明出现顶端枯死现象且不能形成产量。相关性分析结果表明,土壤含盐量与草决明的株高增量、地上部分生物量和产量均呈显著负相关,其中与株高增量的相关系数绝对值(0.983)最大。综上所述,短期低盐(0.2%)胁迫可以促进草决明的生长;株高增量可以作为草决明全生育期的耐盐鉴定指标。

In order to investigate the response of Cassia obtusifolia to salt stress and determine its salt tolerance identification index,the identification method of coastal saline soil gradient was used,the effects of different salt stresses with soil salt content of 0.1%（CK）,0.2%,0.3%,0.4%,0.5%,0.6%,0.7%,0.8% and 0.9% on the plant height,root length,above ground biomass,underground biomass,yield and 100-grain weight of C. obtusifolia were studied,and the correlation between the main growth indicators of C. obtusifolia and soil salinity was analyzed. The results showed that when the soil salt content was greater than or equal to 0.3%,the growth rate of C. obtusifolia was significantly inhibited,while when that was 0.2%,the plant height growth could be stimulated in short period（30 days） and be obviously inhibited in longer period（more than 30 days）. Under the solt stress of0.2%-0.3%,the aboveground biomass of C. obtusifolia increased significantly than that of CK. Under the solt stress of 0.2%-0.9%,the main root length of C. obtusifolia was not significantly different from that of CK.Under the salt stress of 0.4%,the yield of C. obtusifolia reached the highest, but it was not significantly different from that of CK. When the soil salt content was greater than or equal to 0.5%, the fresh weight of aboveground and underground of C. obtusifolia was higher than those of CK. When the soil salt content was geater than or equal to 0.6%,the plant height decreased significantly,when that was geater than or equal to 0.8%,the top died without yield. The results of correlation analysis showed that the soil salt content was significantly nega-tively correlated with the increment of plant height,aboveground biomass and yield of C. obtusifolia. The absolute value of correlation coefficient between plant height increment and soil salinity was the largest（0.983）. In summary,the short-term low-salt（0.2%） stress could promote the growth of C. obtusifolia. The increment of plant height could be used as a salt tolerant identification index for the entire growth period of C.obtusifolia.