Abstract:Leaf epidermis of 45 species of Machilus Nees were observed under light microscope (LM) and scanning electron microscope (SEM), of which 31 species were reported for the first time. The results showed that leaf epidermal cells were polygonous or irregular in shape. Stomatal complexes only present on abaxial epidermis and the stomata was paracytic type. There were five types of anticlinal walls of abaxial and adaxial cells (straight, rounded, undulated, sinuous, straight-curved). Trichomes on abaxial epidermis exist (sparse, dense or very dense) or not. Ornamention types of periclinal walls could be divided into punctuate, smooth and striate (or wavy striate). Ornamention of periclinal walls on inner side of abaxial epidermal cells varied widely (irregular, smooth, roughly reticular, micro hairy, granular, scaly). These characters could help to discriminate different species and reveal the relationship within Machilus. Therefore, they were of significance in studying on classification and phylogenetic relationship of Machilus.

Abstract:Microsporogenesis and male gametophyte development of Torenia fournieri were investigated by techniques of paraffin sections and ultra-thin sections. Each flower of Torenia fournieri has four stamens, and each anther has four pollen sacs. The microsporocyte developed into tetrahedral or isobilateral tetrad through meiosis. The mature pollen grain of Torenia fournieri is 2-cell type with three germination apertures. The development of anther wall is dicotyledonous type, and the tapetum is glandular. Most processes of microsporocyte development are normal, however, the abnormal degradation of microspore cytoplasm is often observed at tetrad stage. It suggested that the abnormal meiosis of microspore mother cell might lead to pollen abortion, which may be one of the main reasons for the low setting rate of Torenia fournieri.

Abstract:The pollination vectors of Cycas elongata were studied using exclusive method and introduction insects. The results showed that the seed setting were 55.3% and 57.2% by wind and insect as pollination vector, respectively, which were lower than that under natural pollination (63.5%). The pollinating peak of C. elongata was at the day, and little in the dark. The pollen grains by wind were more within 3 m from the male plant, and decreased markedly over 3 m. It was conclude that wind and weevils were effective pollination vectors for C. elongata, which inconsistent that Zamiaceae was host-specific insect pollination.

Abstract:Based on the study of type specimens and protologue, the name Dendrocalamus hamiltonii Nees et Arn. ex Munro widely used in Chinese literatures is a misidentification of D. parishii Munro; D. semiscandens Hsueh et D. Z. Li is reduced to a synonym of D. hamiltonii.

Abstract:Chirita luzhaiensis Yan Liu Y. S. Huang & W. B. Xu, a new species of Gesneriaceae from limestone areas in Guangxi, China, is described and illustrated. The new species is similar to Chirita gueilinensis W. T. Wang, but it differs in its leaf-surface villous and pubescent adaxilly, anthers glabrous, filaments geniculate near base, staminodes 3, glabrous, and flowering period from December to January of the following year. It was only found in two karst caves from Zhongdu Town of Luzhai County, Guangxi, China.

Abstract:The seedlings of Bruguiera gymnorrhiza were cultured under 25‰ salinity for 4 months, then the total RNA were extracted from leaves. Following the protocol of SMARTTM cDNA Library Construction kit, the higher quality cDNA library was constructed. The primary titer of the cDNA library was about 1×106 cfu mL-1, its recombinant efficiency was calculated as 94.4%, and the size of the insert DNA fragments was ranged from 1 kb to 2 kb. Ninety-six randomly selected recombinant clones from the cDNA library were sequenced to produce 94 expressed sequence tags (ESTs), among which 81 unigenes (including 5 contigs and 76 singletons) were generated after quality control and assembly of sequences, they were all homologous to the sequences in NCBI Nr database by blastx analysis (E<10-5). These unigenes involved in the processes of respiration, photosynthesis, glucose metabolism, amino acid metabolism, fatty acid metabolism, biosynthesis of unsaturated fatty acids, etc, and had relation to the damage repair, endocytosis, and PPAR signaling pathway.

Abstract:Using the cDNA from the branch cambium of Anthocephalus chinensis as the template, the degenerate primers by reference to the α-Expansin gene (EXPA) sequences in other plants were constructed for RT-PCR. Taking the production of the amplification as the starting information, The full-length cDNA of expansin gene was obtained by RACE, named as AcEXP1. It was 979 bp in length (GenBank accession No. FJ417847) with 777 bp ORF, encoding 258 amino acid, which had the typical conserved sequence and domain of Expansin. There were 85%, 85%, 84%, 83% homology with Populua tomentosa, Populus tremula×P. tremuloides, Prunus cerasus, Petunia×hybrida, respectively. It provided the foundation for studying the relationships between EXP gene and growth rate, wood quality of the xylem of Anthocephalus chinensis.

Abstract:The genetic diversity of Aquilaria sinensis (Lour.) Gilg was investigated by using ISSR molecular markers. The results showed that there was high genetic diversity at the species level, and relatively low at the population level, in which the Maoming population (MM) had the highest genetic diversity. Significant genetic differentiation was found among populations of A. sinensis with GST＝0.4425, it showed that the genetic differentiation within population was bigger than that between populations. The analyses of UPGMA and PCA revealed that 8 populations of A. sinensis were divided into two lineages, lineage Ⅰincluded 5 populations located in Guangdong (MM, GG and GZ), Fujian (FJ) and Hainan (HN), and lineage Ⅱ comprised 3 populations in Guangxi (GX) and Yunnan (YX and YM). At species level, the gene flow with Nm＝0.6633<1 was very limited, which lead to high differentiation among populations. The limitation of gene flow mostly occurred between two lineages, while the gene flow was frequent within lineage with Nm>1 in recent historical period. The main reason of genetic differentiation was geographical factors, which Yunkai Mountains located at borderline of two lineages hindered the gene flow between two lineages.

Abstract:The vector pBI121 particle, which contains Camv35S promoter, kanamycin resistance gene, GUS reporter gene and GAI gene, was transfered into the Hevea brasiliensis anther callus by particle bombardment. The regenerated plantlets were obtained in the subculture media supplemented with kanamycin of 50 mg L-1. PCR and Southern Blotting demonstrated that the GAI gene was transferred into the H. brasiliensis genome successfully.

Abstract:The latex physiological parameters, such as total solid content, inorganic phosphorus, thiols, sucrose content, and invertase activity, and the yield in three clones (Reyan 7-33-97, Reyan 8-79 and PR107) of Hevea brasiliensis were analyzed. The results showed that there were significant difference in latex yield and physiological parameters among the three clones at early latex productive stage and tapped without ethrel stimulation. The latex yields were in order as: Reyan 8-79>Reyan 7-33-97>PR107. The activity of latex invertase had positive correlation to latex yield (P<0.01), while the other physiological parameters had not. The cumulative rainfall before tapping had different effects on the three clones, in which PR107 had the most influence, so it seemed to be an important factor in latex yield. These results suggested that there were specificity in latex production among clones, and it needs establish clone-suitable tapping systems.

Abstract:The biomass of root, stem, leaf and flower, as well as the relationship of biomass allocation were studied from 60 flowering plants of Aster subulatus Michx. in the field. The results showed that the module biomass of A. subulatus was decreased in the order of stem>flower>root>leaf at flowering stage. Their variation coefficient was 57.15%, 64.66%, 57.65%, and 55.2%, respectively, which exhibited high phenotypic plasticity. The variation coefficient of biomass ratio was higher in flower than in other organs, which showed that this weed had high ability to adjusting reproduction allocation. Plant height had significant positive correlation with each module biomass and increased in the power function with the latter increment. Biomass allocation of flower had significant positive correlation with total biomass, but did not that of other organs. The biomass allocation was transferred from nutrition module, supporting module and photosynthesis module to reproduction module. In summary, A. subulatus had better assignment strategy for resource and stronger adaptive ability to heterogeneous environment.

Abstract:The variation patterns of species diversity of forest community in Xiaozhaizigou Nature Reserve were studied by systematic survey along altitudinal gradients, and the relationships between environmental factors and species diversities were analyzed by using Detrended Canonical Correspondence Analysis (DCCA). The results showed that the species diversities was in order of herb layer> shrub layer > tree layer. In tree layer, altitude was the most principal factor on distribution pattern of species diversity. With increment of altitude, species richness and diversity in tree layer decreased, and evenness of tree layer had no obvious changes. In shrub layer and herb layer, the soil nutrient status, such as the contents of organic matter and total nitrogen played important roles in distribution pattern of species diversity. There were not obvious relationships between species diversity and some topographic factors, such as slope, slope aspect, et al.

Abstract:The morphological traits, such as seedling height and basal diameter of 1-year-old seedlings of 18 provenances of Magnolia officinalis, were measured from June to October, 2008, and the genetic variation, growth rhythm and their relationships with environmental factors were studied. The results showed the extremely significant differences in seedling height and basal diameter among the 18 provenances, and also a significant correlation each other. For all of the provenances, the growth of seedlings was slower from June to July and after September, and more rapid from July to September. Furthermore, the environmental and geographical factors significantly affected on genetic variation of the Magnolia officinalis provenances, and the latter was more dominant. Moreover, the 18 provenances of Magnolia officinalis could be divided into 5 groups according to the two dimentional Non-matric Multidimensional Scaling in seedling height and basal diameter, and 3 superior provenances were screened out based on the merits of seedling growth, such as Daoxian, Sangzhi and Anhua.

Abstract:Hedi Reservoir, located in the north of Leizhou Peninsula, is a large and mesotrophic reservoir. To understand the structure and variation of phytoplankton community in the reservoir, phytoplankton was sampled at five sites in February, July, September and December of 2003. Total phytoplankton biomass ranged from 0.156~2.548 mg L-1, mainly contributed by cyanobacteria and diatom. The structures of phytoplankton community at five sites varied markedly and seasonally from spring to winter, and the dynamic pattern of phytoplankton community was quite similar among the five sampling sites. The phytoplankton biomass in flood season was higher than that in dry season. The phytoplankton benefited from high temperature in flood season and nutrient input with inflow. Phytoplankton biomass showed a spatial gradient from riverine zone to lacustrine zone, corresponding to a decrease in phosphorus concentration. Phytoplankton species was dominated by thermophilous species in tropics, and the dominant species in dry season were markedly different from those in flood season. The dominant phytoplankton species in dry season were Rhizosolenia sp., Cyclotella sp., Melosira granulate and Melosira ambigua, while Cylindrospermopsis raciborskii, and Pseudanabaena limnetica in flood season. Phosphorus was the main factor regulating the variation of the dominant phytoplankton species in flood season. The biomass of first eight dominant species contributed 85%~92% of total biomass, significantly less than that in the temperate lakes with steady structure of phytoplankton community.

Abstract:Style movement is common in plants of Zingiberaceae, Marantaceae, Malvaceae and Passifloraceae, but their modes of style movement are different. The two phenotypic styles in Zingiberaceae move towards opposite directions at the same time. The styles of Marantaceous plants move rapidly after the trigger was touched. The stylar branches of Malvaceous plants curved downward until its stigmas touch the anthers, while in Passifloraceae, the movement of stylar branches is also downwards, but they rarely touched the anthers. The movement of styles plays important roles in their pollination and mating system.

Abstract:Glycine betaine is an important osmotic regulator in plants. Many plant cells rapidly accumulate glycine betaine under adverse conditions, including low temperature to maintain an osmotic balance. This article provides an overview of the mechanism of improving cold resistance of plant by glycine betaine and its application, including glycine betaine biosynthesis, its protection mechanism under cold stress, the transformation of glycine betaine synthetase genes, and the effect of exogenous glycine betaine on improving cold resistance of plant.