中国桫椤科植物的配子体世代研究和保护生物学初步探讨
其他题名Studies of Gametophyte Generation and Preliminary Conservation Biology of Cyatheaceae in China
陈贵菊
学位类型硕士
导师成晓
2008-05-21
学位授予单位中国科学院昆明植物研究所
学位授予地点昆明植物研究所
学位专业植物学
关键词桫椤科 配子体 发育 有性繁殖 保护生物学
摘要本文借助显微镜和解剖镜对中国桫椤科代表植物的孢子大小、孢子萌发进行了初步研究;用人工培养方法对孢子进行了培养,详细地观察和描述了配子体世代的发育特征,并对配子体形态特征的系统学意义进行了评价;对配子体在不同的培养条件下的发育形态变化、有性繁殖及污染情况进行了初步研究,并对中国科植物的濒危原因和保护生物学进行了初步探讨,主要研究结果和结论如下: 1. 孢子大小和孢子萌发研究 报道了桫椤科8种植物的孢子大小,孢子的极轴长20.5-37.5μm,赤道轴长32.5-42.0μm。4℃冰箱干燥保存的桫椤孢子寿命达15个月以上。保存3个月的大叶黑桫椤孢子的萌发率相对桫椤科植物其它几种同期保存的孢子萌发率偏低。 2. 配子体世代的特征及其系统意义评价 中国桫椤科植物的配子体世代的特征:孢子正四面体型,三裂缝,近极面观三角形,赤道面观扇形或半圆形,孢子萌发类型为Cyathea-型。丝状体2-5细胞,多为2-3细胞。配子体发育类型为铁线蕨型兼槲蕨型。成熟原叶体心形或蝶形。精子器由5个细胞组成;颈卵器位于心形原叶体腹面,垫状体上靠近顶端凹陷的部位;颈部由4列细胞组成。多细胞鳞片状毛状体在原叶体趋于成熟时产生,位于原叶体的背腹面,与颈卵器区相对应的位置。以上特征为该科植物的正常发育特征,在科内各属种之间无明显的规律性差异。配子体在丝状体、片状体,原叶体阶段都存在不正常的发育形态,且成熟原叶体在生长后期存在营养繁殖,配子体的这些特性在各个种之间无差别。 作者认为桫椤科植物配子体的发育特征在科一级的系统分类中具有重要意义,但在科内属种水平的系统分类上并不具很大的参考价值。 3.不同培养条件对中国桫椤科植物配子体世代的形态发育和有性繁殖的影响 桫椤科植物的配子体发育对基质、光照、相对湿度具有较高的依赖性。红土基质培养、深层液体培养、光照不足及相对湿度过低均会引起桫椤科植物配子体形态发育的不正常或有性繁殖的失调。腐殖质土上长期单独隔离培养的桫椤属植物的原叶体能进行自体自交且产生孢子体,较易产生原叶体的多克隆增殖并产生多株幼孢子体。配子体在培养过程中很容易受污染,主要污染物有细菌, 真菌,藻类和一些藓类植物。 4. 濒危原因及保护措施 配子体世代可能存在的濒危原因:①配子体生长发育和繁殖过程易受环境条件影响。配子体本身遗传因素来源单一,适应环境的能力和竞争能力差。 保护措施:①加强桫椤科植物迁地保护和就地保护。②改善桫椤科植物的生境条件,保留原始森林周围的缓冲带。③人工繁殖孢子体幼苗,并将其回归自然。
其他摘要Spore size and spore germination of representative species of Cyatheacae in china were observed by means of light microscopes and anatomical lens. Spores were cultured in different ways. Detailed characteristics of the gametophyte generation of all species were observed and the developmental morphology changes, sexual reproduction of certain gametophytes and contamination across the cultures were investigated. Significance of gametophyte characteristics to the fern system was cosidered and the factors to endanger the gametophytes and the conservation of the Cyatheaceae plants were primarily studied. Main study results and conclusions are as follows: 1. Studies on spore size and spore germination of Cyatheaceae in China Spore sizes of eight species of Cyatheaceae in China are studied, the polar axis size is 20.5-37.5μm and the equatorial axis size is 32.5-42.0μm. Spores of A. spinulosa deposited in 4℃ refrigerator for fifteen months keep a high germination rate. Among spores of three months deposited time, the spores of A. gigantea have lower germination rate than those of other species. 2. Characteristics of gametophyte generation of Cyatheacae in China and their systematic appreciation. Characteristics of gametophyte generation of Cyatheacae in China: All spores are typical trilete, tetrahedral. Spore outlines are triangular from a polar view and are hemispheric or flabellate from the equatorial view. Spore germination is of Cyathea-type. Protonema is of 2-5 cells, usually 2-3 cells. Gametophyte exhibits Adiantum-type development, with occasional Drynaria-type development. Mature prothalus is cordate or butterfly-shaped. Antheridium is formed by 5 cells, and the archegonium is born near the notch on the ventral face of the cordate prothalus, whose neck is composed of four tiers of cells. Multicellular scary hairs form on the archegonial region, dorsal and ventral surfaces of the prothallus. The normal characteristics above show no evident and disciplinary difference among genera and species. Protonema, cell plate and prothallus all have abnormal developmental morphology, furthermore, the old prothallus can exibits vegetative growth, and the two traits of the gametophyte have no difference among different species studied. The author believes the gametophyte developmental characteristics of Cyatheaceae are of significance to define a family but hard to distinguish the genera and species. 3. Effects of different cultural conditions on gametophyte morphology development and sexual reproduction of Cyatheacae in China Gametophyte development of Cyatheacae badly relies on the medium, light and humidity. Cultured on the crimson soil or deep in the liquid culture or under the conditions lack of enough light and humidity, the gametophyte can be abnormal in the morphology and sexual reproduction. The isolated cultured gametophytes of Alsophila can do intragametophytic selfing to produce sporophytes, also they are apt to produce many clones of gametophyte from one old prothallus. All the clones can each produce a sporophyte. The main contaminants are bacteria, fungi, algae and moss during the cultures. 4. Endangerment factors in the gametophyte generation and conservation strategies of Cyatheaceae in China ①Enhance the management on the off site conservation and on site con- conservation. ② Improve the habitats of Cyatheacae plants,preserve the buffer places of the virgin forests. ③Develop manual propagation of sporophytes and return them to the nature.
页数88
语种中文
文献类型学位论文
条目标识符http://ir.kib.ac.cn/handle/151853/334
专题昆明植物所硕博研究生毕业学位论文
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陈贵菊. 中国桫椤科植物的配子体世代研究和保护生物学初步探讨[D]. 昆明植物研究所. 中国科学院昆明植物研究所,2008.
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