Abstract:Systematic treatment of genus Vins L. from China is shown to be 42 species, 1 subspecies and 12 varieties included in 1 subgenus, 5 sections and 4 series. In this paper descriptions are presented of 3 new sections (Sect. Sinocineriae F. S. Wang et C. S. Zhu, Sect. Romanetianae F. S. Wang et C. S. Zhu and Sect. Wuhanenses F. S. Wang et C. S. Zhu), 2 new state and combination sections (Sect. Labruscoideae (Planch.) F. S. Wang and Sect. Labruscae (Planch.) F. S. Wang), 3 new series (Ser. Adstrictae F. S. Wang，Ser．Piasezkianae F．S．Wang and Ser．Davidianae F S．Wang),1 new variety(V. amurensis Ruper．var．funiushanensis F．S．Wang)and a new combination variety (V．flexuosa Thunb．var．wallichii（DC.) F.S.Wang )．A key to the sections and series is given．

Abstract:Sterculiaceae is a polytypic family with greatly diverse characteristics in Malvales.Till now many authors have no uniform agreement on the demarcation and the numbers of genera since E. P. Ventenat established this family in 1830. According to our studies, we agree that Erythopsis should be separated from Firmiana. Pentapetes should not be placed in Malvaceae, its characters are quite different from that of Malvaceae, so it is better tomaintain it in the Sterculiaceae. On account of the pollen morphology and some other characters, Craigia is similar to that of some genera of Tiliaceae, and should be placed in Tiliaceae, but the flower and fruit characters of which are quite different from Excentrodendron and Burretiodendron, so we suggest establishing a new subfamily, namely Craigioideae S. J. Xu et Hsue subfam. nov. in the Tiliaceae to accommodate the Craigiae.Pentapetes, Corchoropsis, Paradombeya and Melhania should be placed in Sterculiaceae.

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Abstract:Various classification systems of vegetation in Guangdong Province had been proposed for specific purposes. They are not completely suitable for the purpose of mapping digitized vegetation distribution with the assist of geographic information system, global position system and remote sensing. The author proposes a new scheme for the division of vegetation type in Guangdong Province. In this paper, a complete list of coniferous forest in Guangdong is presented, viz. 2 vegetation types, 4 sub-vegetation types and 14 vegetation formations and their representative associations： 1．Warm coniferous forest：(A)Subtropical evergreen coniferous forest：(a)Formation Pinus massoniana；(b)Formation Cunninghamia fanceolata；(c)Formation Pinus kwangtungensis；(d)Formation Tsuga longibracteata；(e)Formation Podocarpus nagi；(f)Formation Fokienia hodginsii；(B)Subtropical deciduous coniferous forest：(g)Formation Glytostrobus pensilis；(h)Formation Taxodium distichum；(C)Subtropical needle-broad 1eaves mixed forest：(i) Needle-broad 1eayes mixed forest dominated by Pinus massoniana；(j)Needle-broad 1eaves mixed forest dominated by Cunninghamia janceofata；(k)Needle-broad 1eaves mixed forest dominated by Podocarpus fleuryi；(l)Needle-broad leaves mixed forest dominated by Pinus kwanotungensis；(m)Needle-broad leaves mixed forest dominated by Tsuga tongibracteata；2. Hot coniferous forest：(D)Tropical evergreen coniferous forest；(n)Formation Pinus latteri.

Abstract:Progress in the study of molecular mechanisms including water stress responses in plants such as drought, high salt and low temperature is reviewed. The variety and functions of the products of water-stress-induced genes and their genetic engineering are discussed. Areas requiring further research are highlighted.

Abstract:Based on Zhang's model for Populus tremula var. davidiana and Pinus yunnanensis forests, a mathematical model of forest population density regulation during self-thinning is presented. The new model was tested using the Algorithms of Contraction-Expansion. The results showed that the new model could fit the observed data very Well. Algorithm of Contraction-Expansion used to optimize nonlinear equation is rational, which will enrich the research method in this field. The new model in the study of density regulation 1aw in Cunninghamia lanceotata forest is sarisfactory and can provide usefu1 information for the management of Cunninghamia lanceolata forest．

Abstract:Daily gas exchange, stomatal conductance and water use efficiency in summer leaves of 6-8 years old Ormosia pinnata were undertaken in a mixed forest of Heshan Hilly Land Interdisplinary Experiment Station in 1995. Results showed that the daily variations of net photosynthetic rate (Pn) and transpiration rate (Tr) exhibited a two-peak pattern. Pn was mainly affected by light, and had no obvious correlation with air temperature, leaf temperature and humidity. Tr correlated with light, air temperature and leaf temperature positively，but negatively with the humidity. Stomatal conductance appeared more seusitive to humidity than to light and temperature．Stomatal conductance and Pn responded independently to environmental factors．Water use efficiency of Ormosia pinnata peaked in the early morning and demonstrated a significant correlation with stomata1 conductance in the daytime．

Abstract:The contents of endogenous IAA, ABA, iPAs, ZRs, GA1+3, GA4+7 and ethylene in three phenotypes of cucumber hairy roots transformed by Ri T-DNA from Agrobacterium rhizogenes R1000 were assayed by enzyme-linked immunosorbent assay (ELISA) and gas chromatography, respectively. The 3 phenotypes of cucumber hairy roots were described by the authors and published in Acta Botanica Sinica 1998, 40(5).470-473. The results showed that the contents of endogenous IAA, ABA and GAl +3 in hairy roots were highest in phenotype III，and less in descending order in phenotype II and phenotype I，whereas the amount of GA4+ 7 was in oppsite order，GA4+ 7 content in hairy roots of phenotype III was lowest and could not be detected．The contents of iPAs and GAl+3 in control roots and RlO00-transformed hairy roots were much higher than those of ZRs and GA4+ 7，respectively．However，the contents of iPAs and ZRs in R1000-transformed hairy roots were higher than those in control roots．The ability of ethylene production in R1000-transformed hairy roots was much higher than that in cucumber control roots．

Abstract:In this paper, we used modified CTAB method to extract genomic DNA from litchi for amplifying RAPD markers. We got 37 polymorphic RAPDs out of 259 total RAPDs from 34 litchi cultivars with 50 random primers. The results showed that these 34 cultivars could be divided into 4 groups. Group I included "Zhuangyuanhong", "Yuanhong", "Guilin", "Songjiaxiang", "Taiwanli", "Xiafanzhi", "Dongliu No. l", "Feizixiao", "Baitangying", "Xiangwan", "Lusha". Group II comprised "Wulizi", "Shuidong", "Wuye", "Caijiawanzi","Qingkenuomici"," Nuomici",Group III included "Guiwei", "Guangming"," Bailizhi","Chenzi" , "Lanzhu", "Jidi", "Taslniu". Group Ⅳ consisted of "Huitoujiang","Putaoben", "HuaizhV", "Nanhaili", "Dazao", "Zaohong"，"Huoshaoli", "Wuyejiu"，"Midingxlang", "Luhebao". The results of cluster suggested that the polymorphism of litchi germplasm was narrower than expected.

Abstract:The explants of young sheath and in vitro basal shoot fragments of vetiver (Vetiveria zizanioides) were used to study the somatic embryogenesis and shoot formation. The results showed that auxin was the key factor for the induction of somatic embryogenesis from the explants. Shoot organogenesis originated from the germination of somatic embryos which could be induced on induction media supplemented with NAA or low concentration of 2,4-D. An efficient recycle induction, regeneration and propagation system of vetiver were established.

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Abstract:The occurrence of oxidative burst in plant-pathogen interactions is reviewed and some characteristics of oxidative burst are summarized. The mechanism involved in the generation of active oxygen species in plant-pathogen interactions as well as the possible functions that may contribute to disease resistance are discussed.

Abstract:In this review, we briefly give an overview of molecular approaches that have been sucessfully taken in the studies on plant cold tolerance. In particular, we discuss the role of membrane lipid, cellular antioxidative ability, cold regulatory proteins, and calcium messenger system on the regulation of plant cold tolerance. Strategies and perspectives in using molecular biology to improve cold tolerance of plants are outlined.