Floral Organogenesis of Titanotrichum oldhamii (Gesneriaceae)

Floral organogenesis of Titanotrichum oldhamii (Hemsl.) Soler., the only species in the genus and endemic to East Asia, was observed under SEM. We found that the development of calyx, corolla and androecium belongs to pentamerous pattern. They come respectively from primordia of calyx, corolla and androecium, and all differentiated from the flower primordium. The zygomorphism of corolla and androecium is derived from quicker growth of the upper lip of corolla and delay in development of the staminode. Initiation of sepal primordia and their development are not consistent in order; the order of initiation is from adaxial central primordium, abaxial two primordia and finally lateral two primordia, while the order of development is first adaxial central sepal, lateral two and finally abaxial two. Sepals are valvate in flower bud. Initiation of corolla lobe primordia and their development are consistent in order, i.e. first abaxial central lobe (central lobe of the lower lip), lateral two (lateral two lobes of the lower lip) and finally adaxial two (two lobes of the upper lip). The aestivation of corolla is imbricate, and the order from outside to inside is the central lobe of the lower lip, lateral two of the lower lip, and finally two of the upper lip or lateral two lobes of the lower lip, two of the upper lip and central one of the lower lip. Stamen primordia are alternate to the corolla lobe primordia, with the anterior two primordia later than the posterior two in initiation; staminode primordium is simultaneous with the posterior two in initiation, but smaller, and opposite to the adaxial carpel (upper lip of stigma). Compared to the patterns of floral organogenesis of Rehmannia (Scrophulariaceae), Whytockia and Rhynchoglossum (Gesneriaceae), the present authors found that the floral organogenesis is diverse and does not form two distinct patterns among these four genera. Based on the results we tend to consider that the conventional demarcation between the Scrophulariaceae and Gesneriaceae using number of ovary locules (two vs one) and placentation (axile vs parietal) is questionable.

Pattern and Significance of Seedling Development in Titanotrichum oldhamii (Gesneriaceae)

The seedling development of Titanotrichum oldhamii (Hemsl.) Solereder has been investigated to provide insight into the evolution and systematic position of Titanotrichum. In T. oldhamii, the size differentiation of the two cotyledons begins while the hypocotyl grows. However, both of the two cotyledons develop normally and locate at the same level. Finally, the two cotyledons are almost equal in size. The aerial shoot (including stem and leaves) is produced from the permanent activity of the apical meristem in the plumular bud. Even though the seedling development in Titanotrichum basically conforms to the general growth pattern of the seedling in the Cyrtandroideae, it is remarkably different from that of other Cyrtandroideae. Based on the revealed evidence in seedling development in Titanotrichum and other comparative data, the authors have evaluated the possible evolutionary pathway of Titanotrichum and further discussed the familial placement of this genus.

Oreocharis xieyongii,an unusual new species of Gesneriaceae from western Hunan,China

A new species,Oreocharis xieyongii T.Deng,D.G.Zhang&H.Sun,from Hunan Province,central China,is described.The combination of purple zygomorphic corolla with longer adaxial lobes and exserted stamens defines the species and discriminates it from all other current Oreocharis species.Morphological traits of the new species were compared to those of two similar species,Oreocharis xiangguiensis and 0.rubrostriata.Phylogenetic analysis indicates that the new species is nested within the Oreocharis.Although only half of Oreocharis species were included in our study,evolutionary character analysis indicates that the ancestral states of the genus are likely the purple corolla,longer abaxial lip and inserted stamens.The longer adaxial lip is perhaps an apomorphy and only present in O.xieyongii and O.rubrostriata.Both morphological and molecular evidence suggest that O.xieyongii is a taxon new to science.

Effects of the Substrate pH on the Growth of Wild Gesneriaceae Plants

The cultivation experiment was carried out on five species of Gesneriaceae plants （ Oreocharis benthamiivar, reticulate, O. argyreia, O. benthamii, Chinita laxiflora, and C. depressa）. The growth traits including crown volume growth, number of leaves and chlorophyll content of each plant cultivated in different pH substrates were measured and analyzed. The pH and conductivity of the original habitat soil were measured as well. The results showed that these five species of Gesneriaceae preferred acidic environment, which could grow well in the matrix of 5 -6 pH range with the steady physiological indicators. The physical and chemical properties of the original habitat soil showed that these five species were resistant to barren, while favored humid environment and a large quantity of water. It is necessary to adjust physical and chemical properties of matdx according to their habits to improve their growth in the cultivation.

Effects of Different Substrate Composition on Growth of Gesneriaceae Plants

The cultivation experiment was carried out to investigate the effects of dif-ferent proportions of peat soil, perlite, vermiculite and yel ow mud on growth of Gesneriaceae species （Chirita gueilinensis, Sinningia speciosa, Lysionotus pauci-florus, Hemiboea henryi, Aeschynanthus acuminatus, Saintpaulia ionantha）. The growth traits of each plant growing in 7 different matrix materials were investigated. The plant height, crown width and chlorophyl content of each plant were mea-sured. The results showed that the best substrate ratio was peat soil∶vermiculite=2∶1 for C. gueilinensis, L. pauciflorus and H. henryi; peat soil∶perlite∶vermiculite = 2∶1∶1 for S. ionantha; peat soil∶vermiculite∶yel ow mud=2∶1∶1 for S. speciosa; peat soil∶per-lite∶vermiculite∶yel ow mud=2∶1∶1∶1 for A. acuminatus.

光照强度对苦苣苔科植物生理生化特性的研究

以苦苣苔科植物蚂蝗七、牛耳朵、吊石苣苔、纤细半蒴苣苔等为分析材料,研究不同光照强度对净光合速率、光能利用率、光合色素含量、丙二醛含量、干物质积累、叶片结构等相关生理生化的影响,以期为提高苦苣苔盆栽花卉品质做技术指导,为园林绿化植物栽培提供理论基础。分析表明:部分苦苣苔科植物幼苗期光照强度25~100μmol·m^(-2)·s^(-1)是适宜的,散射光更有利于生长;光照强度在100μmol·m^(-2)·s^(-1)以下有利于牛耳朵、蚂蝗七、吊石苣苔、纤细半蒴苣苔生理生化反应;光照强度在600~700μmol·m^(-2)·s^(-1),牛耳朵具有较高的光利用能力;大岩桐幼苗期光照强度达到110μmol·m^(-2)·s^(-1)有利于生长,植株生长后期,光照强度在1100~1600μmol·m^(-2)·s^(-1)是适宜的。在苦苣苔科植物栽培过程中根据品种特性、生长习性、栽培光环境给予适宜的光照强度。

Mahuangchiside, a New Flavone Glycoside from Chirita fimbrisepala

A new flavone glycoside, named mahuangchiside, was isolated from the root of Chirita fimbrisepala Hand.-Mazz. The structure was elucidated as 5,4'-dihydroxy-6-methoxyflavone-7-O-beta-D-xylopyranosyl(1-->2)-beta-D-xylopyranoside on the basis of spectral analysis (H-1-H-1 COSY. C-13-H-1 HETCOR and HMBC) and chemical evidence.

七种苦苣苔科植物对光照度的适应性

对苦苣苔科植物光照度适应性进行研究,以提高苦苣苔盆栽花卉品质,并推动其在园林中的合理配置应用。测定蚂蝗七、牛耳朵、银色鹿角、纤细半蒴苣苔、革叶粗筒苣苔、吊石苣苔、粉绿异裂苣苔7种苦苣苔科植物在不同遮光情况下的丙二醛、可溶性蛋白质及叶绿素含量等生理指标,观察其生长量。综合分析比较表明,7种苦苣苔科植物都有较强的耐阴性,在光照度为2 000~8 000 lx条件下能正常生长。对光照度的适应性由强到弱依次为吊石苣苔、粉绿异裂苣苔、银色鹿角、革叶粗筒苣苔、蚂蝗七、纤细半蒴苣苔、牛耳朵。