喀斯特土壤上香樟幼苗接种不同AM真菌后的耐旱性效应

Drought Resistance of Cinnamomum camphora Seedlings Inoculated with Different AM Fungi in Karst Soil

为探索喀斯特土壤适生植物香樟幼苗在接种不同AM真菌后的耐旱适应性,进行了香樟幼苗接种幼套球囊霉(Glomus etunicatum)和层状球囊霉(Glomus lamellosum)后水分胁迫处理试验。结果表明:(1)接种AM真菌显著提高了香樟幼苗的生物量积累,AM促进植株生物量效应依次为中度>轻度>正常>重度,同一水分胁迫处理下生物量幼套球囊霉>层状球囊霉。(2)中度干旱下香樟幼苗菌根依赖性最大,幼套球囊霉接种植株的菌根依赖性较层状球囊霉大。(3)接种AM真菌显著提高了植株叶片可溶性糖、可溶性蛋白质和脯氨酸含量,并降低了丙二醛含量;在正常供水下植株叶片可溶性糖、可溶性蛋白质和脯氨酸含量层状球囊霉接种>幼套球囊霉接种>对照,干旱胁迫下表现为幼套球囊霉接种>层状球囊霉接种>对照;干旱胁迫下的幼套球囊霉接种植株丙二醛含量低于层状球囊霉接种植株。(4)总体上,可溶性糖与脯氨酸相关性极显著,可溶性蛋白质与丙二醛之间呈显著负相关性。幼套球囊霉接种香樟幼苗的耐旱性高于和层状球囊霉接种香樟幼苗。

Drought resistance of Cinnamomum camphora seedlings inoculated with different AM fungi （Glomus etunicatum and G. lamellosum） under drought stress in Karst soil was studied in this paper. The 80 d-old seedlings were exposed to four drought stress treatments of 60 days： severe （35%- 45% of field capacity, FC）, moderate （50% -60% of FC）, mild （65% -75% of FC） and well watered （80% -90% of FC）. Biomass accumulation of individual plants and osmoregulation in the leaves were measured in this paper. The results showed that： （1）Biomass of seedlings significantly increased after the AM fungus inoculation. The order of effects on biomass showed moderate 〉 mild 〉 well watered 〉 severe in all water treatments, G. etunicatum 〉 G. lamellosum as well. There were significant differences in seedlings biomass between well watered condition and severe water stress but not between moderate and mild water stress. （2） It represented a better mycorrhizal dependency of plants under moderate water stress compared with all the other water conditions while differences in dependency were significant under severe stress but the others were not, mycorrhizal dependency of C. camphora inocuhed G. etunicatum was higher than G. lamellosum in all water treatments. （3）Compared with non-inoculated plants, concentration of soluble sugar, soluble protein and proline were higher while malondialdehyde was lower in leaves of inoculated plants. There was a tendency of G. lamellosum 〉 G. etunicatum 〉 ck for soluble sugar, soluble protein and proline in leaves under well watered condition, however it changed G. etunicatum 〉 G. lameUosum 〉 ck while water decreased. The concentration difference in malondialdehyde was not significant. However,it decreased rapidly in G. etunicatum compared to G. lamellosum while enhancing water stress. The ranks of malondialdehyde contents were G. eturdcatum 〈 G. lamellosum 〈 ck with the enhancement of water stress. There were significant differences among three inoculation treatments under severe water stress. Analysis of correlations of metabolic substances showed that there was extremely significant correlation between soluble sugar and proline while significantly negative correlation between protein and malondialdehyde in host plants leaves. （4） The differentiation of AM fungus on drought resistance was distinct when water stress was aggravated. As a whole, drought resistance of G. etunicatum was better than G. lamellosum species in Karst area restoration.