接种丛枝菌根真菌对土沉香幼苗耐旱性的影响

Effects of mycorrhizal fungi on the drought tolerance of Aquilaria sinensis seedlings

接种不同地区的幼套近明球囊霉(Claroideoglomusetunicatu,CE1、CE2)和摩西斗管囊霉(Funneliformismosseae,FM1、FM2)于珍贵树种土沉香(Aquilaria sinensis)幼苗,采用模拟土壤干旱胁迫,研究接种菌根真菌对土沉香的耐旱性影响。结果表明,随着土壤干旱胁迫的加剧,未接菌组的叶绿素a和叶绿素总含量呈显著下降趋势,接菌组叶绿素含量高于未接菌组;在干旱胁迫下,接菌组的可溶性蛋白含量上升,中度干旱胁迫以上,接菌FM1和FM2组可溶性蛋白含量显著高于CK组。随着干旱胁迫程度的增大,接菌组幼苗SOD酶和POD酶活性呈先上升后下降趋势,但接菌组SOD酶和POD酶活性高于CK组。土壤干旱使植物体内MDA含量上升;在中度干旱时接菌组MDA含量高于CK组;当土壤水分达到重度干旱胁迫时,接种FM2、CE1和CE2处理组MDA含量显著高于CK组。研究表明,在干旱胁迫下,土沉香菌根化苗能提高植物体内渗透调节物质和抗氧化酶活性,维持较高的叶绿素含量,从而提高植物耐旱性。模糊隶属函数值分析结果表明,无论是轻度干旱还是重度干旱,接种菌根真菌幼苗的耐旱能力强于未接菌组,接种摩西斗管囊霉菌种强于接种幼套近明球囊霉菌种,其耐旱能力从大到小依次为菌株FM1>FM2>CE2>CE1。

Four endomycorrhiza fungi isolated from different areas of Claroideoglomus etunicatu （CE1, CE2） and Funneliformis mosseae （FM1, FM2） were used to inoculate the seedlings ofAquilaria sinensis, a rare species in China. The effects of mycorrhiza on the drought tolerance of the seedlings were studied under three simulated drought conditions in the pot experiments. The results showed that, under soil drought condition, the contents of chlorophyll a and total chlorophyll significantly decreased in non-inoculated treatment. The total chlorophyll con- tent in the seedlings with inoculated treatment was higher than the non-inoculated ones. The soluble protein con- tent in the seedlings with inoculated treatment was increased under the drought stress. Under the moderate drought stress, the content of soluble protein in shoots with inoculated FM1 and FM2 treatments was significantly higher than the control （CK）. The enzymatic activities of super oxide dismutase SOD） and peroxidase （POD） in the in- oculated seedlings showed a trend of increasing firstly and then decreasing under continuous drought stress and the enzymatic activities of SOD and POD in the inoculated seedlings were higher than those in the non-inoculated seedlings under drought stress. Under the moderate drought condition, the content of malondialdehyde （MDA） in seedlings with inoculated treatment was higher than that of CK. When the soil was under severe drought stress, the MDA contents in seedlings with inoculated FM2, CEI and CE2 treatments were significantly higher than those of CK. This results suggested that under the drought stress, mycorrhizal fungi can improve the drought tol- erance of the seedling by increasing the soluble protein content, MDA content and the activity of antioxidant en- zyme, and maintaining high chlorophyll content. The subordinative function analysis showed that the drought tol- erance of the inoculated seedlings was higher than the non-inoculated seedlings under various drought stresses.The order of the drought tolerance of the inoculated seedlings was FMI〉 FM2〉 CE2〉 CE1.