天麻的营养繁殖茎及其抑菌功能

天麻9Gastrodia elata Bl.）与蜜环菌（Armillaria mellea (Vahl.ex Fr.)Quel.)营共生生活,在正常情况下蜜环菌只侵染种麻及分化生长出的营养繁殖茎的表皮、皮层及大型细胞层。种麻的大型细胞层及营养繁殖茎隔离区的空腔细胞层和木栓细胞层,都是种麻与新生麻的防御结构,它们保护新生麻不遭蜜环菌病理侵染而正常生长。冬季,天麻进入冬期,隔离区的木栓细胞层形成断裂层,此层细胞是新生麻能够安全越冬的最后一道防御结构。     

天麻种子萌发过程与开唇兰小菇的相互作用*

实验表明开唇兰小菇Mycena anoectochila可与天麻Gastrodia elata种子共生促进其萌发形成原球茎。 菌丝自胚柄端的柄状细胞侵入天麻种子原胚,进一步在皮层细胞中扩展,在外皮层细胞中形成发育良好的菌丝结,菌丝完整而有活力; 在内皮层细胞中则被消化,菌丝衰败、扁化。菌丝在原球茎细胞内的分布被限制在原球茎基部的柄状细胞、外皮层细胞和内皮层细胞,菌丝均被电子透明物质包围, 外围环绕有原球茎细胞质膜, 该界面使侵入的菌丝与原球茎细胞质相隔离,也是两共生生物间进行物质交换的所在。上述菌丝侵入至被消化的过程在整个原球茎发育过程中可反复进行。     

Study of Factors for Cultivating the Orchid Species Gastrodia elata,a Traditional Chinese Medicine

The orchid speices Gastrodia elata is a valuable traditional Chinese medicine and has been widely applied for treating a variety of diseases. The yield of wild Gelata is very limited since its vegetative growth is exclusively dependent on its symbiosis with the fungus Armillaria mellea, from which Gelata is able to obtain nutrients from rotten wood in the forest. To develop a standard for cultivating Gelata in large quantities, four factors that may influence the yield of Gelata need to be further investigated, including cultivation environment, inoculation volume of Armillaria, wood from different tree species, and the effect of fertilizer on the maturation of Gelata. To optimize these factors, a large scale orthogonal experiment was performed in the farmland of Xiaocaoba, Zhaotong, Yunnan Province. Among the four factors tested, inoculation of Armillaria played the most important role in the maturation of Gelata. The yield of mature tubers, in terms of both tuber weight and quantity, on open ground is greater than that in forested areas. Of the 12 tree species tested, Dipentodon sinicus stimulated the largest amount of growth of Armillaria and produced the greatest yield of Gelata in the farmland. In comparison to the other factors tested, fertilizer showed no effect on the yield of G-elata.     

湖北野生天麻的遗传分化及栽培天麻种质评价

采用7条ISSR引物对天麻(Gastrodiaelata)8个自然居群和6个人工栽培居群共483个样本的居群遗传多样性进行了初步检测,共检测出清晰、重复性好的DNA带77条,其中64条为多态性带,总多态位点百分比PPB=83.12%。遗传多样性分析结果表明:天麻自然居群的遗传多样性参数分别为:多态位点百分比PPB=59.09%,有效等位基因数Ae=1.29,Nei’s遗传多样度H=0.176,Shannon’s多态信息指数I=0.270,明显高于人工栽培居群(PPB=35.71%,Ae=1.16,H=0.100,I=0.155),揭示出栽培居群存在明显的遗传基础狭窄和遗传均质性问题。UPGMA聚类分析表明,自然居群与栽培居群存在明显的分化而分别聚为两大类群。自然居群间基因分化系数GST=0.2558,与AMOVA分析所揭示的居群间遗传变异量占总变异的27.25%的结果相近,说明天麻自然居群间亦存在一定程度的遗传分化;居群间基因流(Nm)为1.4547,相对较弱,可能对自然居群的遗传分化有一定影响。自然居群聚类结果显示出一定程度的地理区域聚类趋势,但Mantel检验表明自然居群间遗传距离与地理距离并不存在显著相关(r=0.1669,P=0.2110),揭示出天麻自然居群的分化现状可能是其生活史特性、地理隔离与人为破坏综合作用的结果。栽培居群的遗传均质化趋势,揭示了引种驯化的瓶颈效应和长期无性繁育所导致的遗传多样性丧失,也反映出栽培天麻种质的遗传基础狭窄。而栽培居群与自然居群间存在着明显的遗传分化,反映天麻栽培居群与自然居群间可能存在基因流的阻断。     

The Structure and Antifungal Functions of Vegetative Propagation Corm of Gastrodia elata

The growth of Gastrodia elata Bl. and Armillaria mellea (Vahl. ex Fr.) Quel. shares a special symbiotic relation. In general, A. mellea invades the G. elata , the epidermal cells, the cortical cells and the large cells of the growing vegetative propagation corm of G. elata . The empty cavity cells, the cork cells of the isolation in the vegetative propagation corms and the large cells of G. elata were the defensive structure, protecting the new G. elata from pathological invasion by A. mellea . In winter, G. elata enters the stage of hibernation.　The faulting layer derived from the cork cells of the isolation was the last defensive structure by which new G. elata could safely live through the winter.     

盐胁迫对金牌美达丽和猎狗种子萌发的影响

用不同浓度的NaCl、KCl、MgSO₄和3种盐的复合溶液胁迫金牌美达丽和猎狗种子,观察其发芽率和萌发后子叶及胚根生长情况,对其进行生态阈限分析。结果表明:金牌美达丽和猎狗种子萌发对盐生境的适应性均很强。低浓度NaCl、KCl及复合盐溶液对猎狗种子萌发有促进作用。随盐胁迫强度上升,发芽率呈逐渐下降趋势,高浓度盐明显延缓种子的初始萌发时间,抑制幼苗正常生长。高浓度盐显著降低种子发芽率,但不同盐分对种子发芽率影响不显著。MgSO₄溶液对种子发芽率没有显著抑制现象,但对金牌美达丽胚根的生长有明显抑制作用。     

盐胁迫下两草种SOD和POD及脯氨酸动态研究

在NaCl、KCl、MgSO₄及其复合盐胁迫下, 研究草坪草-金牌美达丽(Lolium perenne)和猎狗(Fesluca elata) 中脯氨酸含量、超氧化物歧化酶和过氧化物酶活性的变化。结果表明:不同盐分、不同浓度胁迫下脯氨酸含量呈波动式变化, 其峰值出现在较高浓度下, 说明在一定范围内盐胁迫强度越大脯氨酸积累越明显;SOD 的最高值出现在低浓度下, 而最低值无此特点, 不同盐胁迫下的最高值、最低值相差不多, 说明L.perenne 和F.elata 相差不明显;POD 活性随盐浓度增加呈波动性变化, L.perenne (除KCl)和F.elata (除MgSO₄)最高值均出现在低浓度下, L.perenne 的最低值集中在高浓度, 而F.elata 的最低值则集中在低浓度, F.elata在高浓度胁迫下, 处于一个比较稳定的水平, 高于或接近CK, 且各值比较接近, 而在L.perenne 中却没有这一结果。     

天麻种子萌发过程中与其共生真菌石斛小菇间的相互作用

天麻Gastrodiaelata种子与石斛小菇Mycenadendrobii的共生萌发试验表明,石斛小菇可与天麻共生,促进天麻种子发芽并形成原球茎。菌丝主要分布于原球茎的柄状细胞、外皮层细胞和内皮层细胞,在外皮层细胞中形成菌丝结,内皮层细胞中的菌丝则被消化。原球茎细胞中的菌丝均被电子透明物质和原球茎细胞质膜包围而与原球茎细胞质相隔离,菌丝进一步液泡化并最终被水解。含有衰败菌丝的原球茎细胞常被菌丝重新定殖。这一菌丝被消化及菌丝的重新定殖过程在整个原球茎发育过程中可不断重复发生。     

天麻种子与兰小菇共生萌发过程中超微结构变化研究*

天麻Ｇａｓｔｒｏｄｉａｅｌａｔａ种子与兰小菇Ｍｙｃｅｎａｏｒｃｈｉｄｉｃｏｌａ的共生萌发试验表明兰小菇可与天麻种子共生促进天麻种子萌发并形成原球茎。菌丝自胚柄端的柄状细胞侵入天麻种子原胚,其分布被限制在天麻原球茎基部的柄状细胞、外皮层细胞和内皮层细胞内,均被电子透明物质和原球茎细胞质膜包围而与原球茎细胞质相隔离。菌丝在外皮层细胞中形成菌丝结,在内皮层细胞中则被消化,形成扁化、衰败的菌丝或菌丝四块。含有衰败菌丝的原球茎细胞可被菌丝重新定殖,新近定殖的菌丝又被原球茎细胞消化。