Abstract:The geographical distribution of Avena L. (Aveneae, Poaceae) was studied by field investigation and reviewing specimens and literature. The results showed that 29 species in Avena were distributed in Europe, Mediterranean, Northern Africa, Western Asia, Eastern Asia, and the Americas. In China, four species of Avena distribute in high altitude areas in the northern, northwestern, and southwestern provinces. Seven sections are delimited in Avena, including sect. Avenotrichon (Holub) Baum, sect. Ventricosa Baum, sect. Agraria Baum, sect. Tenuicarpa Baum, sect. Ethiopica Baum, sect. Pachycarpa Baum, and sect. Avena. The sect. Ethiopica occurs in Ethiopia, Saudi Arabia, and Yemen, and the remaining six sections occur in Mediterranean, Southwestern Europe, Northwestern Africa, Western Asia, Eastern Asia, and the Americas. The results suggest that the Mediterranean, Northwestern Africa, and Western Asia are the distribution centers and diversification centers of Avena, while the origin center of Avena needs to be further studied.

Abstract:Examination of herbarium specimens has shown that Anemone fulingensis W. T. Wang & Z. Y. Liu (Ranunculaceae) is conspecific with A. prattii Huth ex Ulbr. We therefore reduce A. fulingensis to the synonymy of A. prattii. Pollen grains in A. prattii are revealed to be 6-10-zonocolpate. The geographical range of A. prattii is clarified, and its morphological differentiation from A. delavayi Franch. is discussed.

Abstract:Both herbarium and field observations have shown that Delphinium quinqueflorum W. T. wang (Ranunculaceae) described from Zhongdian, Yunnan, China, is no more than a smaller form of D. thibeticum Finet & Gagnep., a species very common in that area. We therefore reduce D. quinqueflorum to the synonymy of D. thibeticum.

Abstract:Oberonia seidenfadenii (H. J. Su) Ormerod and O. segawae T. C. Hsu & S. W. Chung as two new records of Orchidaceae from mainland China are reported for the first time. The voucher specimens are deposited in the herbarium of the South China Botanical Garden, Chinese Academy of Sciences, Guangzhou (IBSC).

Abstract:A new species of Primula is described and illustrated under the name of P. hydrocotylifolia G. Hao, C. M. Hu & Y. Xu. From general morphology it is clearly allied to the species of section Petiolares subsection Chartacea, which is characterized by the plants being glabrous and efarinose, lacking bud-scales at flowering time, the globose capsule including in the persistent calyx, not opening by valves but crumbling at the membrane apex, and by the leaves with more or less rounded blades and slender petioles. The new species superficially resembles P. veitchiana, but the latter can be easily distinguished by its much taller stature, many-flowered inflorescence and larger flowers.

Abstract:In order to understand the development process of rhizome of Zingiber officinale Roscoe, the microstructure and ultrastructure of Z. officinale rhizome at different developmental stages were studied under light and electron microscopes, and the developmental process of secretory cavities in rhizome was also observed. The results showed that there were cortex, endodermoid layer and central cylinder within epidermis in young rhizome. The secondary thickening meristem originated from the cells located in the outermost of the central cylinder. Cell division and enlargement resulted in the development of rhizome. There were a lot of starch grains in parenchyma cell, which varied in shape, size and number during the development. Secretory cavities were widely distributed in Zingiber. There were 3 stages during the whole development: the formation of original cell groups, the ontogenesis of secretory cavities and the formation of mature secretory cavities. The ginger essential oil mainly synthesized in the mitochondria, plastid and cytoplasm. This research supplied theory foundation for medicinal exploitation and utilization of Z. officinale.

Abstract:In order to understand the phylogenetic significance of farina in gametophytes of fern, the gametophyte development of five Aleuritopteris species were observed. The results showed that the gametophytes (usually female gametophytes) of A. squamosa had also farina phenomena. Based on the evidence of chloroplast rbcL sequences, it was confirmed that A. squamosa is a member of the Hemionitids, one of four well-supported clades resolved by molecular data. The American Notholaena, within which the farinose gametophytes were formerly reported, was resolved as monophyletic, forming a sister group to the Hemionitids. As the farinose gametophyte now observed in two of the four clades of cheilanthoid ferns (Heminitids and Notholaenids), it was postulated that the farinose gametophyte would be derived independently at least twice in the evolution of the cheilanthoid ferns. The fact that the farina is produced exclusively in female gametophytes implies that the occurring of the farina would be relevant to the gender differentiation and the embryo formation in cheilanthoid ferns.

Abstract:In order to understand the introduced plants in Nansha Islands, the southernmost of China, the introduced plants in seven reefs were investigated from Augest to September, 2012, and the growth status of these plants were analyzed. The results showed that there were 79 species of introduced vascular plants, belonging to 62 genera and 36 families. Based on species in neighouring Xisha and Nansha Islands, some plant species suitable to grow in Nansha Islands (reefs) were also proposed, it would provide references to vegetation restoration and greening of Nansha Islands in the future.

Abstract:In order to understand the mechanisms of soil carbon sequestration of plantations in South China, the total soil respiration (R_s) and autotrophic respiration (R_a) and their seasonal dynamics of five plantations in Heshan, Guangdong at 2-5-year-old were studied from 2007 to 2012. The plantations include Eucalyptus urophylla plantation, 30 species mixed plantation, 10 species mixed plantation Castanopsis hystrix plantation, and Acacia crassicarpa plantation. The results showed that average R_s, R_a and contribution rate of R_a to R_s (RC) of these plantations ranged within 81.3-103.9 mg C m^-2h^-1, 11.2-22.3 mg C m^-2h^-1, and 12.4%-26.9%, respectively. The average R_s in wet season of these plantations were 311.4% higher than that in dry season; while R_a and RC had not significant difference between wet and dry seasons. The soil temperature in wet season had significant relation with R_s among five plantations, which explained the variation of R_s for 90.2%, but they had no relation in dry season. The difference of microenvironment and soil condition among these young plantations was no obvious, in which soil was still restoring from disturbance, so that soil respiration had no significant difference among five plantations.

Abstract:In order to understand the symbiosis of arbuscular mycorrhizal fungi (AMF) with Compositae invasive plants in Guangzhou, the AMF colonization rate and spore density of 7 Compositae invasive plant species in four habitats were studied, and the effect of soil factors on AMF was also analyzed. The results showed that all the investigated plants were colonized by AMF, AMF spores were detected from all soil samples. AMF colonization rate showed significant difference among hosts, but not among habitats. AMF spore density was significantly different both among hosts and habitats, among which, spore density was significantly higher in artificial green land, farmland and orchard than that in forest surround and coastal area. Correlation analysis showed that spore density was negatively correlated with soil organic matter content in farmland and orchard, AMF colonization rate was positively correlated with total N content in forest surround, AMF colonization rate was negatively correlated with available N content and available P content in artificial green land and coastal area, respectively. These could play an important role in understanding the invasion mechanisms of Compositae species.

Abstract:In order to understand the leaf functional traits in different strains of Prunus campanulata, the leaf index, specific leaf area, chlorophyll content and leaf dry matter content in four strains were studied. The results showed that there were significant differences in leaf characteristics among the four strains. Leaf index had negative correlation with leaf dry matter content (P<0.05). Specific leaf area had significant positive correlation with chlorophyll content (P<0.01) while had significant negative correlation with leaf dry matter content (P<0.01). By comprehensive evaluation, the strain of CB3 has high chlorophyll and leaf dry matter contents, long flowering and dense flowers, so that it's recommended as an ornamental and street tree species.

Abstract:In order to understand the canopy effects of pioneer trees on seedling growth of other speciecs in rocky desertification area of southwestern Guangxi, the survival and growth traits of Cyclobalanopsis glauca and Lonicera maackii under three pioneer tree canopy, such as Delavaya toxocarpa, Leucaena leucocephala and Zenia insignis, were studied by field plot experiment. The results showed that the three pioneer trees could reduce the light intensity and improve soil physical characters, reduced soil bulk density, increased the total porosity and the field capacity, but they could not change soil chemical features. All the three pioneer trees had certain nurse effects on the survival and growth of C. glauca seedlings. Z. insignis and Leucaena leucocephala improved the survival but inhibited the growth of Lonicera maackii seedlings. D. toxocarpa decreased significantly the survival and growth of Lonicera maackii seedlings. Whether they improved or inhibited the seedling growth, the three pioneer trees had more effects on the seedling height and branch growth than those on basal diameter. Therefore, the pioneer trees D. toxocarpa, Leucaena leucocephala and Z. insignis could be selected as the nurse plants for C. glauca seedling in rocky desertification area in southwestern Guangxi, but Lonicera maackii should be planted outside the pioneer tree canopy to avoid shade effect.

Abstract:In order to evaluate resource statuts of Camellia mairei var. lapidea endemic in Guizhou, the age structure and spatial distribution pattern of the population were studied by quadrat method. The results showed that the age structure of C. mairei var. lapidea population was decline type. The population density was in the order of middle-age trees > old trees > young trees. Spatial distribution pattern of C. mairei var. lapidea population was different in different development stages, which young trees and middle-aged trees had cluster distribution, and old trees were nearly cluster distribution to random distribution. The spatial pattern at different development stages had negative or no relation. C. mairei var. lapidea is rare and endangered species because of propagation biological characteristics and population habitat heterogeneity. So, it was effective measure to protect C. mairei var. lapidea germplasm resources by setting up in situ reserves and increasing populations by carrying out introduction and cultivation.

Abstract:In order to understand the key environment factors on flowering of Camellia oleifera, the physical and biochemical indexes in flowering process of C. oleifera ‘Changlin 4’ were studied. The results showed that under different environments, the contents of soluble protein, soluble sugar and growth regulators, including auxin, gibberellin, cytokinin and abscisic acid, in old leaves, new leaves and stems had significant differences in flower bud differentiation period (May 19), but had no direct relations with flowering. The buds were full and growth was fast, and flowering time was early too under N treatment. The light and growth regulators, except of GA, cannot promote C. oleifera blossoming. The flowering rate was the highest under nutrient treatments, and then was under water and heat treatments, but under hot and K treatments, the end stage of flowering significantly delayed. Therefore, the suitable conditions, such as heat, nutrient and water, are in favour of blossom in C. oleifera, but auxin and cytokinin inhibit its blossom.

Abstract:Tillering (branching) is a major determinant of crop yield that is controlled by plant hormones, growth and environment factors, et al. Some new branching genes and regulatory mechanisms recently reported in monocots have contributed to our knowledge of tillering/branching. The tillering/branching relate genes and regulatory mechanisms represented by gramineous plants were reviewed. The similarities and differences of tillering/branching regulatory mechanism between eudicots and monocots were compared in the perspectives of hormone, gene, transcription. These provides theoretical basis for the formation of plants yield, the adaptation to environment, and the enhancement of survival competition ability.