真姬菇菌丝体对硒耐受性的研究

Tolerance of Hypsizygus marmoreus mycelium to selenium

摘要:

【目的】探讨真姬菇Hypsizygus marmoreus菌株菌丝体对硒的耐受特性。【方法】利用平板培养法测定不同硒浓度处理下菌丝平均生长速率，拟合硒与菌丝生长速率的关系，记录菌丝萌发、菌落形态特征，做还原培养验证，利用显微镜观察硒对菌丝分枝、大小、锁状联合形态以及表面结构的影响。【结果】真姬菇菌丝体对硒耐受特性的研究表明：当外源硒浓度≤50 mg/L时，对真姬菇菌丝生长有促进作用，促进效果因菌株不同而存在差异，但与Control Check (CK)相比均无显著差异(P>0.05)。当外源硒浓度≥75 mg/L时，对真姬菇菌丝生长产生抑制，真姬菇菌丝对硒最大耐受浓度为150?200 mg/L。还原培养表明：这种抑制具有恢复性；硒浓度与菌丝平均生长速度符合Cubic回归曲线，且可决系数(即拟合度)较大。显微镜观察结果表明：在外源硒浓度较低时，真姬菇菌丝体粗细均匀、健壮饱满、分枝较多、表面光滑、锁状联合明显、结构饱满。在外源硒浓度较高时，菌丝粗细不一，皱缩呈长扁条形，锁状联合结构塌陷、干瘪，表面凹凸不平，变成类似竹节状结构，菌丝尖端逐渐被球状分生孢子替代，部分分枝甚至完全异化为分生孢子或厚垣孢子。【结论】硒浓度≤50 mg/L时对真姬菇菌丝生长有促进作用，硒浓度≥75 mg/L时有抑制作用，高浓度硒对菌丝有毒害作用，但这种毒害作用是可逆的。

Abstract:

[Objective] To explore the tolerance characteristic of selenium of Hypsizygus marmoreus mycelium strains. [Methods] To determine the average growth rate of mycelium at different concentrations of selenium by using the plate culture method and fitting the relationship between selenium and mycelial growth rate. Record the mycelium germination, the morphological characteristics of colony and do the restoring culture to verify. Using microscopic to observe the effect of selenium on the hyphae branch, size, lock-like joint morphology and surface structure. [Results] The results of experiment showed that when exogenous selenium concentration ≤50 mg/L, it promoted the growth of mycelium. The promoting effect vary in different strains, but compared to Control Check (CK), there is no significant difference (P>0.05). When exogenous selenium concentration ≥75 mg/L, the growth of H. marmoreus was inhibited. The maximum tolerance concentration of selenium is 150–200 mg/L. Restoring culture showed that this kind of inhibition could be restored; selenium concentration and the average growth rate accords with mycelium Cubic regression curve and the coefficient of determination (degree of fitting) is large. The results of microscopy observation indicated that when the concentration of exogenous selenium is low, the mycelia showed the following characteristic: even thickness, robust and full, more branches, smooth surface and distinct lock-like joint clear structure. At higher concentrations of exogenous selenium, thickness of the mycelium is irregular and it shrinked to long flat strip. The lock-like joint structure collapsed and wizened, the surface is uneven and became bamboo-like structure. The tip part of hyphae was gradually substituted by spherical conidia and some branches even were completely alienated into conidia or chlamydospores. [Conclusion] when the selenium concentration ≤50 mg/L, it has a promoting effect on the growth of mycelium; when selenium concentration ≥75 mg/L, it inhibited the growth. High concentration of selenium has toxic effects on the mycelia, but the toxic effects are reversible.