紫荆花粉离体萌发条件的研究

以紫荆(Cercis chinensis Bunge)花粉为材料,采用人工培养法研究了紫荆花粉离体萌发的最适条件.结果表明:蔗糖、硼酸在一定质量浓度范围内能促进花粉的萌发,最适花粉萌发的质量浓度分别为蔗糖50 mg/L以及硼酸20 mg/L,最佳萌发温度20℃.正交试验设计结果表明:花粉萌发的最佳质量浓度分剐为70 mg/L蔗糖以及18mg/L硼酸,最佳萌发温度为22℃,此时的萌发率可达60.51％.     

Growth responses of an African savanna tree, <Emphasis Type="Italic">Bauhinia thonningii</Emphasis> Schumacher,to defoliation,fire and climate

This study investigated the growth responses to defoliation, fire-exposure and climate factors of a widespread Africana savanna tree, Bauhinia thonningii Schumacher, at a site in central Zambia. Experimental trees (n = 47) were either exposed to fire (n = 12) in the first half of the dry season or protected from fire (n = 35). Some of the fire-protected trees (n = 12) were subjected to artificial defoliation in two consecutive years. Phenological responses (bud break, leaf flush and leaf production) to fire-exposure and defoliation were monitored on permanently marked sample shoots over a 2-year period. Radial tree growth (diameter at 1.3 m above ground) was measured annually over a 7-year period from 1998 to 2005. During the first two years, defoliation and fire-exposure advanced the onset of bud break and leaf flush but fire-exposed trees produced significantly less leaves than did trees protected from fire, probably because scorching caused more severe shoot die-back than is normal. Leaf production was also significantly affected by experimental treatments and their interaction with year. Although treatments had significant short-term effects on radial growth, previous-year growth significantly influenced current-year growth, thereby confirming the existence of autocorrelation in the time-series growth data of B. thonningii. The interaction between previous-year growth and climate factors explained a significant proportion (25–40%, P < 0.001) of the variance in annual tree growth. Variogram models predicted that a 2-year manual defoliation treatment would shorten the longer-term growth cycle while continuous fire-exposure extended the cycle by one year. The results are useful for the management of savanna trees.     

中国羊蹄甲属新分类群

<正> 在《中国植物志》第39卷中,作者对羊蹄甲属采用了广义的概念,属以下分为3个亚属:羊蹄甲亚属subgen.Bauhinia,厚盘亚属subgen.Lasiobema Korth,显托亚属subgen.Phanera(Lour.)Wunderlin,Larsen et Larsen.在编写过程中,发现一些新分类群,现报道如下:     

羊蹄甲属的系统与生物地理学：1．厚盘组的分支分析

羊蹄甲属厚盘组作为一个分类实体包含有约１８个种,本组植物主要分布于中国南部及中南半岛等地,其中很多种类在其分布区内地理替代现象相当明显。对此组的分支系统学研究,一方面有助于对本组种类系统进化关系的理解,另一方面又为对热带亚热带亚洲大陆各区系之间关系。的理解提供帮助,为本地区的分支生物地理学研究提供材料．本文用３０个形态及叶脉脉序性状对厚盘组进行了分支分析．云南羊蹄甲被选作外类群,内类。群包括龙须藤亚组及攀援羊蹄甲亚组的所有１８个种。分析产生了８个最简约的分支图。分析还表明攀援羊蹄甲单独作为一个亚组是不可取的,厚盘组的分类及生物地理学需要进一步的研究．     

岷江干旱河谷土壤水、氮和磷对小马鞍羊蹄甲幼苗生长的影响

资源阈值对植物的影响是恢复生态学的重要议题.通过近似模拟岷江干旱河谷自然干旱条件下水、氮和磷的阈值,设计析因实验,研究了一个生长季节内小马鞍羊蹄甲幼苗生长、生物生产量、资源利用效率和存活率的变化.结果表明：高水（40%田间持水量）、高磷（24 mg P·kg^-1）和低氮（100 mg N·kg^-1）处理分别促进了幼苗生长,增加了生物生产量,提高了存活率和水分利用效率,氮磷交互作用显著,水分和养分交互作用不明显.高氮（240 mg N·kg^-1）有强烈的负效应,高磷可以增大根面积、根长和根生物量,提高对氮和磷的吸收,缓解高氮的抑制作用.养分利用效率和幼苗根茎比呈显著正相关,并保持相对稳定.高水、高磷和低氮耦合有效地促进了幼苗的生长,而低水、低磷和高氮耦合则明显抑制了幼苗生长.     

洋紫荆凝集素的分离纯化和性质

利用酸化处理的Ｓｅｐｈａｒｏｓｅ ６Ｂ亲和柱从洋紫荆种子中分离纯化出了洋紫荆凝集素（ＢＶＬ）,其比活性比抽提液提高了１５９倍,活力回收率为４９．０％。ＢＶＬ分子量为８１０００,由两个相同的亚基组成。等电聚焦凝胶电注测得其等电点为４．９５。其紫外吸收高峰在２７６ｎｍ处。ＢＶＬ具一定的的热稳定性和酸碱稳定性。Ｎ－乙酰－Ｄ氨基半乳能强烈地抑制ＢＶＬ对兔红细胞的凝集作用。乳糖、半乳糖也有较强的抑制定性。Ｎ     

Multivariate chromatographic fingerprint preparation and authentication of plant material from the genus Bauhinia

Multivariate analysis and statistical mixture designs were used for chromatographic fingerprint preparation and authentication of the plant material of three species of the genus Bauhinia. The extracts were analysed by reversed-phase high-performance liquid chromatography. Mixture design gave an optimum solvent composition for extracting components from the plants of 36% dichloromethane, 17% ethanol and 47% ethyl acetate (by volume), while an optimum mobile phase for chromatographic analyses was found to be 27% methanol, 27% acetonitrile and 46% of water (by volume). Results from principal component analysis, hierarchical analysis and soft independent modelling by class analogy showed that Bauhinia candicans cannot be synonymous with B. forficata Link. It was also possible to trace the metabolic profile without identifying its chemical constituents and to determine a chromatographic discriminating region. The characteristics responsible for discrimination between B. candicans and B. forficata were more polar substances that presented peaks with retention times around 1.65 and 1.81 min.     

羊蹄甲属植物种子表面微形态观察

利用光镜和扫描电镜对羊蹄甲属21种(含1亚种、2变种)的种子进行观察,结果显示,羊蹄甲属植物的种子颜色、形状和外种皮纹饰多样,还发现种脐位置、假种皮裂片、拟透镜状突起和种皮表面纹饰有一定的相关性:即没有假种皮裂片,拟透镜状突起在种子表面不明显,具网状纹饰的种子其种脐位于种子亚顶部的位置,而非顶部位置。此外,大部分羊蹄甲亚属种子的表面纹饰为皱波状,而显托亚属的纹饰没有皱波状纹饰,却以网状纹饰居多。分析认为,羊蹄甲属植物中种皮网纹状纹饰可能是比较进化的特征;并认为种脐在亚顶部位置,没有假种皮裂片,拟透镜状突起在表面不明显,具网状纹饰的种子应是羊蹄甲属内较进化的式样。     

A flavanone and a dihydrodibenzoxepin from Bauhinia variegata

Phytochemical analysis of the root bark of Bauhinia variegata Linn yielded a new flavanone, (2S)-5,7-dimethoxy-3',4'-methylenedioxyflavanone (1) and a new dihydrodibenzoxepin, 5,6-dihydro-1,7-dihydroxy-3,4-dimethoxy-2-methyldibenz [b,f]oxepin (2) together with three known flavonoids (3-5). The structures of the new compounds were determined on the basis of spectral studies.