Abstract:In order to understand the limiting factors of photosynthesis of tree species in north-subtropical forest, China, the photosynthesis characteristics of nine common tree species was studied by using improved Farquhar model. The results showed that the maximum photosynthesis rate (P_max) and carboxylation efficiency (CE) of deciduous Liquidambar formosana and Sapium sebiferum were higher than those of other evergreen species; the activity of ribulose bisphosphate carboxylase oxygenase (Rubisco) was limiting factor of photosynthesis rate in two species. The CE and P_max of Cyclobalanopsis glauca were the highest among seven evergreen species, and its strong photosynthesis capacity might derive from high maximum carboxylation rate (V_cmax) and triose phosphate utilization rate (TPU). The P_max of shade-tolerant shrub Fatsia japonica and Camellia uraku was low because of low g_m and high dark respiration rate (R_d). The low photosynthesis capacity under low light intensity (200 μmol m^-2s^-1) was due to low g_m and TPU. The reduction of effective photosynthetic radiation in short term caused g_m decrease by 60.14%. Therefore, the photosynthetic limiting factors of different tree species were different under different environment conditions. It was necessary for reasonable arrangement of tree species and scientific afforestation according to its photosynthetic characteristics.

Abstract:To understand the characteristics of plant community near to Hac Sa Reservior in Macau, the species composition, spatial structure, diversity and plant phenology of the community were studied by field investigation. The results showed that there were 88 species vascular plants, belonging to 47 families and 80 genera in 1200 m² plot. There were no donimant species in tree and shrub layers, the dominant species in herb layer was Lophatherum gracile and interlayer species were rich. The horizontal distribution of species was even. The physiognomy of the community was evergreen throughout the year. The phenology phases of most species had overlapping phenomenon. The duration of leaf spreading phase was long. The flowering focused from May to June and fruit ripening stage from October to November. Therefore, based on community and phenological characteristics of indigenous plants, some ornamental plants were selected for promoting landscape and ecological values as well as ecological restoration in Macau and neighboring areas.

Abstract:In order to reveal dormancy character and geographical variation of Dodonaea viscose seeds, the seeds were collected from Liangshan and Zuolin Xiang in Yuanmou Xian, Yunnan Province, and their germination character was studied. The results showed that seeds from two places had physical dormancy, and the germination rate of seeds treated by hot water was significantly (P=0.001) higher than that of untreated seeds. The width, length of seed, ratio of length to width, and 100-seed weight between Liangshan and Zuolin were very close. Besides, the seed germination and seedling growth of D. viscose had no significant differences between Liangshan and Zuolin. Therefore, seeds from Liangshan and Zuolin had no geographical variation, the two places are feasible to seed collection. But seed dormancy should be broken before sowing to improve germination rate.

Abstract:To understand the distribution of medicinal herb Anoectochilus roxburghii (Wall.) Lindl. in central Guangdong, the ecological-biological characteristics of A. roxburghii in Zhaoqing area were studied. The results showed that there were two wild relatives of Anoectochilus distributed in Zhaoqing, A. roxburghii and A. formosanus, which were rare and endangered, usually A. roxburghii with red leaves as medicine. Anoectochilus roxburghii is typical shallow-root and mid-shade terrestial orchid, growing under southwestern evergreen broad-leaved forest at suitable slope > 45°and canopy density of 60%-80%, with suitable temperature of 12℃-26℃. The development of A. roxburghii population was affected by ecological factors together, such as air humidity, community structure and soil humus composition. The endangered reasons of medicinal herb A. roxburghii were analyzed, and the protection measures were proposed.

Abstract:In order to understand the water-saving irrigation quantity in Shenzhen, the growth and photosynthetic characters of four Liliaceae ground cover plants, such as Ophiopogon japonicas, Dianella ensifolia ‘Silvery Stripe’, Aspidistra elatior and Asparagus cochcinchinensis, were studied under different relative soil water contents by potted water control method. The results showed that all of four ground cover plants grown strongly under relative soil water content of 60% to 65%. Ophiopogon japonicas, Dianella ensifolia cv. ‘Silvery Stripe’ and Asparagus cochcinchinensis grow well with good ornamental value under relative soil water content from 40% to 45%. Aspidistra elatior grows normally under relative soil water content from 20% to 25%. Therefore, it was instructive for water management of Liliaceae ground cover plants.

Abstract:Terrestrial net primary productivity (NPP) is an important component of the surface carbon cycle. In order to deeply understand the effects of human activities on terrestrial ecosystem, it is very necessary to evaluate the relative contributions of climatic fluctuation and land cover change to NPP variations. Based on the scenario simulation method, the CASA (Carnegie-Ames-Stanford Approach) model was used to estimate actual vegetation NPP of Guangdong Province in the year 2000, 2005 and 2010. The relative contribution of climate fluctuation and land cover change to vegetation NPP change was also discussed. The results showed that there was significantly positive correlation between solar radiation and NPP and significantly negative correlation between temperature and NPP, precipitation is not a limiting factor in vegetation growth, the correlation between each climate factor with NPP displayed seasonal and regional difference. Under the constant climate conditions, the land cover change caused an overall NPP gains and its relative contribution to NPP variations was similar to the urban expansion pattern. Regional differences existed in the four eco-regions with the largest contribution in the Pearl River Delta. Overall, the relative contribution of climatic fluctuation was more complex, which depended on the fluctuation characteristics of climate factors and their correlations with NPP; other influence factors (urban heat island, agricultural activities, gardens management and so on) existed some uncertainties and increased NPP as a whole.

Abstract:Two strains of green algae with No. FACHB-1783 and FACHB-1784 were isolated from small ponds in Wuhan, Hubei Province and Xishuangbanna, Yunnan Province, respectively. Their morphology and 18S rDNA sequences were studied. The typical coenobia of two strains are tetragonally arranged in flat, usually 4-16-celled. Cells are broad ellipsoid to irregularly oval, without polar thickenings. Numerous chloroplasts are discoid, each with a pyrenoid. Based on morphological and molecular phylogenetic evidences, the two strains were identified as Makinoella tosaensis Okada, which was considered as a new recorded genus and species of freshwater trebouxiophycean algae from China. The 18S rDNA sequence of the strains showed high similarity (99.6%-99.9%) with those of M. tosaensis Okada from Korea. The phylogenetic analyses based on 18S rDNA sequence showed that all strains of M. tosaensis Okada clustered into a clade with high support values.

Abstract:Delphinium batangense Finet & Gagnep. (Ranunculaceae) is an alpine species widely distributed in western Sichuan and northwestern Yunnan, China, and highly variable morphologically. Examination of both herbarium specimens and living plants has shown that D. chenii W. T. Wang and D. yajiangense W. T. Wang fall within the variation range of D. batangense. Therefore, D. chenii and D. yajiangense are both placed in synonymy with D. batangense herein.

Abstract:During the course of compiling Species Catalogue of China [Volume I-Spermatophytes, (V)-Angiosperms (Rosaceae-Phyllanthaceae)], twelve new combinations for Chinese Argentina Hill (Rosaceae) are proposed here based on the recent studies.

Abstract:The aim was to discuss the origin and systematic evolution of Nai plum (Prunus salicina L. var. cordata Y. He). The pollen morphology of 7 cultivars of Nai plum, 2 cultivars of Chinese plum (P. salicina Lindl. var. salicina) and 1 cultivar of Cherry plum (P. cerasifera Ehrhart.) and 3 cultivars of hybrid plum were observed under scanning electron microscopy (SME). The results showed that 13 copies of material of pollen were with striate-foveolate or cerebroid-foveolate decorations, and the shape of pollen grains was prolate or perprolate which were with three split round in polar view. There were three germination trenches equally spacing with a circular distribution of a N₃P₄C₅ type. The P/E value of Nai plum pollen ranged from 1.82 to 2.02 with size from 823.70 to 970.42 μm², which are among the other 6 cultivars of Prunus. But the perforation densities (0.520-1.141 μm^-2) of Nai plum, except of Zaoyuan younai and Zaoshou younai, are bigger than that of other 6 cultivars. The extine wall of pollen had vallate, and the surface distributed perforation with different size and density. There were rich diversity in uplift and ditch deep of vallate, which early-maturing strain and late-maturing strain of younai plum showed two characteristics in pollen morphology, density of perforation, etc. Thus, the pollen morphology of Nai Plum could serve as an important basis for classification and identification. Cluster analysis showed that thirteen plum germplasms could be divided into 3 groups at genetic distance of 6.19, and each group had Nai plum germplasm. It was suggested that there was close genetic relationship between Nai plum and Prunus. So, there was a possibility that Nai plum originated from hybrid plum through pollen morphology and cluster analysis of palynology.

Abstract:In order to understand the current status of vines in Tongbiguan Nature Reserve, the diversity and composition of vines were studied by field survey. The results showed that there are 676 vine species belonging to 65 families and 209 genera in Tongbiguan Nature Reserve. Dicotyledonous vines donimate in the species composition, with 597 species belonging to 192 genera and 56 families. According to life-form, phanerophyte vines are predominant, accounting for 81.51% of the total. Twining vines are the majority and account for 53.99% of the total. The concept of leaning vines is proposed. High rainfall, undulating altitudes, diverse habitat types, and highly diverse primary broadleaved forests are significant of the enormous abundance of vines in this region.

Abstract:In order to understand the quantitative inheritance of leaf color of tea (Camellia sinesis) spring shoots, the numerical taxonomy of leaf color phenotypes of 68 tea cultivars was studied by using colorimeter. Based on hierarchical cluster from the values of L^*, a^*, b^*, C, and H of the first leaf, the tea cultivars could be divided into seven groups, such as purple, yellow, and green, et al. The color classification by hierarchical cluster had high identity to the CIELab system, which had close relation to the color phenotypes of tea cultivars. The leaf color phenotypes were rich with a zonal distribution at 3D coordinate of L^*, a^*, b^* values, ranging from purple, purple-red and purple-green to yellow, yellow-green and green. Therefore, the numerical taxonomy of leaf color would provide a scientific basis for breeding special color of tea bud-leaf.

Abstract:The mitochondrial DNA (mtDNA) copies of Antirrhinum majus were measured by quantitative PCR method. The results showed that the mean volume of central cell of A. majus was (61570±732) μm³ with (783±25) mtDNA copies. There were similar ratio of volume to mtDNA copy between central cell and egg cell. It was presumed that the abundant mtDNA in central cell might reserve for the early development of endosperm cells.

Abstract:In order to explore the characteristics of infection and damage of citrus black spot to Citrus grandis ‘Guanximiyou’, the changes in hypodermal cell structure were observed under scanning electron microscopy and transmission electron microscopy (TEM) after artificially inoculated with Phyllosticta citriasiana. After pomelo fruits were infected, the tonoplast in hypodermal cell wrinkled, fractured, and eventually vanished. The starch grains in chloroplast disappeared. The plasmolemma wrinkled, invaginated and partly ruptured. The number of mitochondria increased with clear visible grana. The thylakoid swelled and disintegrated. Afterwards, mitochondria underwent morphological changes, including disappearance of two layers of membrane and vacuolization. However, there were no intercellular or intracellular hyphae, and the cell wall remained structurally stable. Phyllosticta citriasiana infected hypodermal cells of ‘Guanximiyou’ through toxins, which probably attack cell membrane structure and cross over cell wall through plasmodesmata.

Abstract:In order to screen and isolate the active constituents from invasive plant Macfadyena unguis-cati L. (Bignoniaceae), the anti-proliferative effects of SMMC7721, Bel7402 by different solvent extraction fractions of ethanol extracts of M. unguis-cati in vitro were studied by using MTT assay. The results showed that the chloroform fraction of ethanol extracts had strong inhibitory effect on liver cancer cells, and then was petroleum ether fraction. An active constituent isolated from chloroform fraction, ursolic acid, had strong inhibitory effect. Therefore, invasive plant M. unguis-cati L. has cytotoxicity in vitro, and one of the main active components is ursolic acid.

Abstract:In order to understand the bioactivity constituents form Derris eriocarpa How, six compounds were isolated from ethyl acetate fraction of ethanol extract of its stems and roots by using chromatographic techniques. On the basis of spectral data, their structures were identified as (-)-maackiain (1), medicarpin (2), emodin (3), (-)-pinoresinol (4), (6R,9R)9-hydroxy-4-megastigmen-3-one (5), 2-methoxygliricidol (6). All these compounds were isolated from this species for the first time. Furthermore, compounds 1 and 2 exhibited significantly inhibitory activities in vitro against some of tumor cell lines and mycobacterium tuberculosis (H₃₇Rv).