摘要
木棉树(Bombax ceiba L.)是干热河谷稀树灌丛和稀树草坡的建群树种,对该区域水土保持和生态恢复有着重要作用.木棉开花结实良好,种子萌发正常,树下却没有天然更新的木棉幼苗及幼树,为揭示这种情况与木棉树下严重入侵的紫茎泽兰的相关性,采用紫茎泽兰根系土壤、叶片和根浸提液及其粉末,结合室内和田间试验,用培养皿滤纸法和盆栽法,综合评价紫茎泽兰对木棉种子萌发和幼苗光合特性的影响.结果表明:(1)紫茎泽兰叶片和根浸提液均显著降低了木棉的种子萌发率和幼苗光合效率,这种抑制程度和抑制发生的时间随浓度升高而加强或提早,无论在低浓度还是高浓度,抑制作用均随着处理时间延长而加剧;(2)在高浓度下,紫茎泽兰叶片对木棉的种子萌发率和幼苗光合效率的抑制作用显著高于根浸提液的,而低浓度下,这种差异不显著;(3)紫茎泽兰根际土壤也显著了降低木棉种子的萌发率和幼苗存活率,一个月后的存活率仅为4.75%,与对照相比下降了90.95%;(4)用紫茎泽兰叶片和根粉末伴土模拟叶片和根分解或半分解物质对抑制木棉种子萌发的影响,当叶片和根粉末与土壤比例按20 g:1 kg处理时,木棉种子萌发率和一个月后的存活率显著降低.由此可见,紫茎泽兰叶片和根系的分解或半分解产物对木棉种子萌发、幼苗光合效率和幼苗的存活能产生抑制作用,是影响干热河谷地区木棉天然更新的重要因素.
Kapok tree（Bombax ceiba）, a dominate tree species in the sparse thickets and savanna vegetation in dry-hot valleys（DHV）, plays an important role in soil and water conservation and ecological restoration in this area. Kapok tree can flower and fruit admirably with good seed germination ratio. However, little is known about why there is no naturally regenerated seedlings or young trees nearby or under the tree. This research aimed to investigate whether this was related to the serious invasion of Eupatorium adenophorum under kapok tree. In order to evaluate the effects of E. adenophorum on seed germination and seedling photosynthetic characters of kapok, the experiments were carried out both in laboratory and field with the rhizosphere soil, extracts and powder of E. adenophorum leaf and root, by using petri dish filter paper and the potted methods. Results showed that：（1） the extract of E. adenophorum leaf and root significantly reduced the seed germination rate and seedling photosynthetic efficiency of kapok, with the degree of such inhibition increasing with the extract concentration. The higher the extract concentration the earlier such inhibition took place. For both low and high concentration, the inhibiting effect aggravated with time;（2） the inhibitory effect on the seed germination rate and seedling photosynthetic efficiency of kapok was significantly higher for the leaf extract of E. aenohporum than the root extract in high concentration, while the difference was not significant in low concentration;（3） E. adenophorum rhizosphere soil also significantly reduced the kapok seed germination rate and seedling survival rate, with the survival rate as 4.75% after one month, 90.95% lower than those of control;（4） when treated with the mixture of leaf and root powder of E. adenophorum and soil with a ratio of 20 g ： 1 kg, the kapok seed germination rate and survival rate showed significant decrease after one month. The results suggested that the decomposition or half-decomposition subs
出处
《应用与环境生物学报》
CAS
CSCD
北大核心
2014年第4期683-689,共7页
Chinese Journal of Applied and Environmental Biology
基金
国家自然科学基金项目(31260175)
国家林业公益性行业科研专项(201104034)
云南省高校科技创新团队建设项目资助~~
关键词
化感作用
木棉
紫茎泽兰
干热河谷
种子萌发率
天然更新
allelopathy
Bombax ceiba
Eupatorium adenophorum
dry-hot valley（DHV）
seed germination rate
natural regeneration
