接种菌根真菌对青冈栎幼苗耐旱性的影响

利用丛枝菌根真菌摩西球囊霉(Glomus mosseae)、根内球囊霉(Glomus intraradices)和外生菌根真菌彩色豆马勃(Pisolithus tinctorius)对石漠化地区造林树种青冈栎(Cyclobalanopsis glauca)幼苗进行接种试验。在大棚盆栽条件下模拟土壤干旱胁迫,研究菌根真菌对青冈栎生长和耐旱性的影响。结果表明:在土壤干旱条件下,接种菌根处理植株生物量显著高于未接种处理(P0.05),菌根依赖性随土壤水分含量降低而升高;未接种处理植株叶绿素含量在土壤干旱条件下显著降低(P0.05),除接种Pisolithus tinctorius处理外,其它接种处理叶绿素含量无显著变化。土壤干旱使植株体内脯氨酸和可溶性糖含量上升,在中度干旱条件下,接种处理可溶性糖含量均显著高于对照处理,接种Glomus intraradices、Pisolithus tinctorius处理脯氨酸含量显著低于对照(P0.05);在重度干旱条件下,接种Glomus mosseae和Glomus intraradices处理可溶性糖含量显著高于对照处理(P0.05),而相应的脯氨酸含量显著低于对照处理。当土壤水分含量在田间持水量55%—65%时,接种处理植株SOD、POD和CAT酶活性显著高于未接种处理(P0.05),在土壤水分含量降至35%—45%时,Glomus mosseae和Glomus intraradices处理SOD酶活性显著高于对照,并且所有接种处理POD酶活性均显著高于对照。此外,在水分干旱条件下,植株全磷和全钾含量也显著高于未接种处理(P0.05)。研究表明,丛枝菌根真菌和外生菌根真菌均能够侵染青冈栎幼苗根系;在干旱胁迫条件下,接种菌根真菌能够提高青冈栎植株生物量、抗氧化酶活性、增加植株可溶性糖含量和促进植株养分吸收,提高植株耐旱性,从而使青冈栎幼苗在岩溶干旱环境下更容易存活。

Effects of mycorrhizal fungi on the drought tolerance of Cyclobalanopsis glauca seedlings

Two endomycorrhiza fungi Glomus mosseae and Glomus intraradices and ectomycorrhiza Pisolithus tinctorius were used to inoculated the seedlings of Cyclobalanopsis glauca, C.glauca is a common species for forestation in karst rocky desertification area in southwest of China. The effects of mycorrhiza on the growth and drought tolerance of the seedlings were studied under three simulated drought conditions in green house pot experiment. Soil water content were maintained 75%-85%, 55%-65% and 35%-45% field capacity respectively. The results shows that, under soil drought condition, the biomass of inoculated treatment was significantly higher than the non-inoculated treatment. Mycorrhizal dependency increase with the soil moisture content reduces. Chlorophyll content of infected treatments were not affected by drought stress except Pisolithus tinctorius treatment, while contrast treatment was significantly decreased under drought condition. Under moderate drought condition, content of soluble sugar in shoots of inoculated treament were significantly higher than the contrast treatment, but the content of proline of Glomus intraradices and Pisolithus tinctorius treatment were significantly lower than that of contrast. The enzymatic activity of super oxide dismutase(SOD), peroxidase(POD) and catalase(CAT) of inoculated seedlings are significantly higher than that of non-mycorrhizal seedlings when the soil water content maitained 55%-65% field capacity. When the soil moisture content maitained 35%-45%, POD activity of all inoculated seedlings are significantly higher than that of contrast, SOD activity of Glomus mosseae and Glomus intraradices treatments are significantly higher than the contrast, while CAT activity of Glomus mosseae and Glomus intraradices treatments are significantly higher than that of non-mycorrhizal treatment.Furthermore, total phosphorus and total potassium content of mycorrhizal seedings significantly higher than that of no inoculated plants under soil drought condition. This research suggest that endomycorrhiza and ectomycorrhiza can infect Cyclobalanopsis glauca seedling. Under drought condition, both mycorrhizal fungi can improve the drought tolerance of the seedling through increasing the biomass, activity of antioxidant enzyme, soluble sugar content and advance the assimilate of nutrient of Cyclobalanopsis glauca seedling. Therefore, mycorrhizal Cyclobalanopsis glauca seedling more easier live under the drought karst environment.