【作者】 郭金丽；

【导师】 李青丰；

【作者基本信息】 内蒙古农业大学 ， 草业科学， 2007， 博士

【摘要】 本文以三种根茎型禾草白草(Pennisetum centrasiaticum )、赖草(Leymus secalinus)和羊草(Leymus chinensis)为材料,对三种禾草的有性繁殖特性、营养繁殖特性及繁殖分配进行了系统的对比研究,分析了三种禾草有性繁殖和营养繁殖的特征和能力及其在种群繁衍和更新中的作用,并探讨了三种禾草的繁殖适应对策。主要研究结果如下:1白草、赖草、羊草的结实率分别为1.85%、55.29%和11.54%。三种禾草的潜在种子产量分别为622.40 kg/hm~2、527.37 kg/hm~2和357.69 kg/hm~2;实际种子产量分别为10.34kg/hm~2、280.55kg/hm~2和38.13kg/hm2,分别占潜在种子产量的1.67%、53.37%和10.67%。2白草种子的发芽率最高,为64.70%,且种子萌发速度快,发芽整齐;赖草和羊草种子的发芽率极低,分别为6.00%和4.00%,且发芽速度慢。白草种子活力和幼苗耐旱性均高于赖草和羊草。3三种根茎型禾草都同时拥有根茎芽和分蘖节芽两种营养繁殖体,两种营养繁殖体在整个生长季中都有产生,且产生高峰期集中于果后营养期。也同时具有由根茎芽发育成根茎芽成株和由分蘖节芽发育成分蘖节成株的两种营养繁殖方式。三种禾草营养繁殖的具体情况有所不同:白草的根茎芽及其形成的根茎芽成株在芽库中和地上分株的总数中占有绝对的优势,白草以根茎芽为主的根茎营养繁殖能力远高于以分蘖节芽为主的分蘖节的营养繁殖能力;赖草的根茎芽及其形成的根茎芽成株在芽库中和地上分株的总数中占有较大的优势,以根茎芽为主的根茎的营养繁殖能力高于以分蘖节芽为主的分蘖节的营养繁殖能力;羊草芽库中根茎芽的数量略高于分蘖节芽的数量,但分蘖节芽的成株能力高于根茎芽的成株能力。4三种禾草同属能够利用根茎进行“行走”的游击型植物,相对于丛生型禾草来说,具有更强的扩展能力。三种禾草相比较而言,白草的克隆构型应趋向于“密集型”,赖草和羊草的克隆构型应趋向于“游击型”。三种禾草的克隆构型在不同的环境水平下,在间隔子长度、分枝强度等方面表现出一定的可塑性变化,但表现并不完全一致。5随着干旱胁迫程度的加强,三种禾草地上枝数目的增量和总芽数均呈下降的趋势,白草的总芽数在同等水分条件下都要高于赖草和羊草的总芽数;白草的地下部分生物量所占比例呈上升的趋势,而赖草和羊草的地下生物量所占比例基本呈下降的趋势;三种禾草在干旱条件下均表现出间隔子长度增加。综上,三种禾草在干旱条件下均形成了一定的适应性反应,白草对干旱胁迫具有更强的适应性。6三种禾草对生殖器官穗部的生物量分配都极低,其中赖草最高,也仅为6.30%,其次为羊草4.26%,白草最低为3.06%;对营养器官的生物量分配均高达90%以上。此种物质分配策略,进一步证明了三种禾草种子繁殖能力弱而营养繁殖能力强。此外,白草地下部的生物量配置为50.01%;赖草和羊草均对地下部生物量配置较少,分别为19.49%和29.27%。白草对地下部的投资远高于赖草和羊草对地下部的投资,三种禾草均具有发达的根茎系统,但白草的地下根茎系统更为发达。7三种根茎型禾草的有性繁殖能力较弱,导致它们有性繁殖能力低的原因各有侧重,三种禾草有性繁殖在其种群的延续和繁荣中作用甚微;三种禾草的营养繁殖占主导地位,在天然植被中主要以为营养繁殖方式实现种群的繁衍与更新,即采取K-对策,以质量取胜。更多还原

【Abstract】 In this paper three rhizomatous grasses were used including Pennisetum centrasiaticum, Leymus secalinus and Leymus chinensis, systematic comparison was studied on their sexual propagation characteristics, vegetative propagation characteristics and reproductive allocation. This thesis analyzed characteristics and ability of sexual propagation and vegetative propagation, renewal function and contribution of population multiply in three grasses, also discussed their strategy of reproductive adaptation. The results were listed as below:1. The seed-setting rate of Pennisetum centrasiaticum,Leymus secalinus and Leymus chinensis were 1.85%, 11.54% and 55.29% . Potential seed yield of three grasses were 622.40kg/hm~2, 527.37kg/hm~2 and 357.69kg/hm~2 , while their actual seed yield were 10.34kg/hm~2, 280.55kg/hm~2 and 38.13kg/hm~2 ,which were 1.67%, 3.37% and 10.67% of potential seed yield.2. The seed germination of Pennisetum centrasiaticum was the highest in three grasses, which was 64.70%, seed germinal speed was quick . The seed germination rates of Leymus secalinus and Leymus chinensis were extremely low ,which were 6.00% and 4.00% respectively, and their seed germinal speed was slow. The seedling vigour and drought resistance of Pennisetum centrasiaticum were higher than that of Leymus secalinus and Leymus chinensis.3. Three rhizome grasses all simultaneously had rhizome bud and tillering bud. Two vegetative forms both appeared during the entire growing season. Their peaks was on the nutrition time of post harvest. they also had two vegetative propagation ways. Vegetative propagation of three grasses were different: the rhizome buds and its mature plants of Pennisetum centrasiaticum took absolute advantage of the total number of buds and upland remets. The vegetative propagation ability of rhizome mainly by rhizome buds was higher than that of tillering bud mainly by tillering buds. The rhizome buds and their mature plants of Leymus secalinus took the more advantage of total number of buds and the upland ramets .The vegetative propagation ability of rhizome was higher than that of tillering bud .The number of rhizome buds of Leymus chinensis was higher than that of tillering buds.4. Three grasses all belonged to“shortstop plants”which could walk by rhizome. their expansion ability were stronger than bunchy grasses. Compared with three grasses, the clone configuration of Pennisetum centrasiaticum tended to be“crowded”and occupied the space by growing dense rhizome system nearby the base rhizome. Leymus secalinus and Leymus chinensis tended to be“shortstop”and good at laying ramets on farther place by expanding the rhizome. In different environment level, the clone configuration of three grasses expressed the certain plastic change on interval length and branching length, but the expression was not completely consistent. It was explained that research about clone configuration and its plasticity changes of relative characteristics could not reach at the general summary stage .5. Along with water stress strengthening, the terdency on the increase of the number of upland branch and the total bud were dropping., The number of pennisetum centrasiaticum’s total buds was higher than that of Leymus secalinus and Leymus chinensis in the same moisture condition. The proportion of underground biomass in Pennisetum centrasisaticum was rising and that of Leymus secalinus and Leymus chinensis were dropping. In the drought condition, interval sub-length of three grasses were all increasing . In conclusion, three grasses formed the certain compatibility in drought condition. Pennisetum centrasiaticum had a stronger compatibility to water stress.6. Biomass for reproductive organ spikes of three grasses were extremely low, Leymus secalinus was the highest which was only 6.3% , that of Leymus chinenisis was 4.26%, that of Pennisetum centrasiaticum was the lowest which was only 3.06%. On the contrary, biomass allocations of vegetation organ of Leymus secalinus, Leymus chinensis and Pennisetum centrasiaticum were 96.94%, 93.7% and 95.74%, this material assignment strategy also proved that the seed reproduction ability of three grasses were weak and the ability of vegetative propagation were strong. The biomass disposition of underground in Pennisetum centrasiaticum were 50.01%, while the biomass disposition of upland in Leymus secalinus and Leymus chinensis were 19.49% and 29.27% respectively. The investment for underground in Pennisetum centrasiaticum was much higher than that of Leymus secalinus and Leymus chinensis. Three grasses all had stronger rhizome system , Pennisetum centrasiaticum’s rhizome system was more developed .7. Sexual propagation abilities of three grasses were weak, the reasons were different. Sexual propagation of three grasses had less effects on their population’s prospering. Vegetative propagation had dominant position. Three grasses realized population’s multiplication and renewal by the way of vegetative propagation in natural vegetation, it was K- strategy which won by quality.更多还原