Abstract:Using the total RNA extracted from Jatropha curcas L. leaves as the template, the degenerate primers were designed according to the reported sequence of squalene synthases gene in other plants, the full-length cDNA of squalene synthase gene in Jatropha curcas L. was cloned using RACE method, which was named JcSQS with 1609 bp in length including a 1242 bp-ORF, and JcSQS was predicted to encode the protein with 413 amino acids. The cloned JcSQS gene contained the typical conserved sequences and domains of SQS genes. The JcSQS protein had high homology with the amino acid sequences encoded by SQS gene in Ricinus communis, Diospyros kaki and Bruguiera gymnorhiza, so on. It laid the foundation for studying the biosynthesis and regulation of terpenoids and steroids in J. curcas.

Abstract:The interaction proteins of rubber elongation factor (REF) were screened using yeast two-hybrid system. A bait vector pBD-GAL4-REF without auto-activation was constructed by subcloning ORF cDNA of REF gene into the yeast two-hybrid vector pBD-GAL4, and the pAD-GAL4-2.1 cDNA prey library was prepared with mRNA extracted from the latex of rubber tree (Hevea brasiliensis). The bait and prey vectors were then co-transformed into YRG-2 yeast competent cells by two-step method. Five proteins interacted with REF were identified by yeast two-hybrid screening method, including two of REF family proteins, and small rubber particle protein (SRPP), translation control of tumor protein (TCTP), elicitor-responsive protein and ubiquitin-conjugating enzyme E2. The data suggested that REF could not only interact with high homologous proteins, but also with other proteins, such as TCTP, and E2, etc. These protein-protein interactions might help to revealing the biological function of H. brasiliensis rubber particles.

Abstract:The effects of Stay-green rice gene (SGR) over-expression and mutation on carbon and nitrogen metabolism in rice (Oryza sativa L.) leaves were studied by using hydroponic culture. The results showed that SGR over-expression reduced contents of soluble protein, chlorophyll and starch, but the contents of soluble sugar and free amino acids increased, as well as the activities of glutamine synthetase (GS) and glutamate synthetase (GOGAT) in rice leaves under normal growth condition. Whereas, SGR mutation increased the contents of starch and soluble protein and improved nitrate reductase (NR) activity. Under nitrogen deficiency, the variation trend of physiological parameters was consistent among the three types of rice except the starch content in SGR mutant rice leaves. These suggested that the changes in SGR level could influence the carbon and nitrogen metabolism in rice leaves.

Abstract:In order to explore the indices and evaluation method of heat tolerance of Rhododendron subgenus Hymenanthes, 4-year-old seedlings of R. jinggangshanicum Tam and R. simiarum Hance were planted in artificial climate chamber under different high temperatures (30℃, 38℃, and with 22℃ as control). The contents of malondialdehyde (MDA), hydrogen peroxide (H₂O₂), proline (Pro), soluble protein, ascorbic acid (AsA) and the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX) were determined after treated for 6 days. The heat tolerance of two species was comprehensively evaluated by principal components analysis and fuzzy subordinate function based on the measurement values of tested parameters. The results showed that MDA, H₂O₂, SOD, CAT, POD, APX were the most important physiological and biochemical indexes for heat tolerance of Rhododendron seedlings. A very significant correlation (r=0.987^**) was found between the subordinate function values (U value) of 6 main indices and U value of whole indices. The U value and increased range of U value in R. simiarum were larger than those in R. jinggangshanicum at 30℃ and 38℃, the evaluation results accorded with their behavior in the field. It is suggested that the method can give an objective evaluation on the comprehensive heat tolerance between different species of Rhododendron subgenus Hymenanthes seedlings.

Abstract:The growth and sensitivity to Leptocybe invasa of 60 clones of Eucalyptus urophylla at 5- or 7-year-old were investigated in Xinhui County, Guangdong Province. The results showed that the growth traits had significant relations among the individuals of clones, and there were no significant correlations between damage index and growth traits. The estimation of genetic parameters showed that E. urophylla clones had high repeatability for resistance to Leptocybe invasa, which could screen rapid growing and resistance to bees clones of E. urophylla. In finally, 6 excellent clones were screened out by independent culling method.

Abstract:The effects of plastic film (PF) residue on morphology and physiological characteristics of tomato (Lycopersicon esculentum L.) seedlings were studied by pot experiments. The results showed that PF residue inhibited growth of tomato seedlings. The plant height, stem diameter, shoot and root fresh weight, root activity and nitrogen metabolism were decreased. However, PF residue also reduced IBA content of root and ABA content increased, which inhibited lateral root growth, and the bigger was residue of PF, the more significant was inhibited effects. It suggested that the residue of PF had serious influences to the growth of tomato seedlings.

Abstract:The influence factors on the dehydration tolerance of Phalaenopsis PLB (protocorm-like body) were studied, including average grain weight and water content of PLB, as well as relative humidity, time, temperature, light period, et al. The results showed that average grain weight of PLB had very significant or significant correlations with water loss rate, water content, relative conductivity and survival after dehydration, respectively. When PLB were dehydrated at high humidity, the bigger average grain weight of PLB, the greater relative conductivity reduced and the survival increased. Both water loss rate and water content of dehydrated PLB had obvious regression relations with dehydration humidity, but not significantly regression relations with dehydration time. The survival of PLB with high water content increased obviously after dehydration, but the percentage of increasing was smaller at high dehydration humidity than that at low dehydration humidity. Under dehydrated at 52% RH for 2 days, plasma membrane damage and mortality of PLB reached critical values. Although the water contents of dehydrated PLB were close, the PLB dehydrated at slow speed had lower relative conductivity and higher survival than those dehydrated at rapid speed. Survival of PLB was high when dehydrated at low temperature or in the dark. Therefore, the dehydration tolerance of Phalaenopsis PLB was extremely sensitive to its weight and water content. Besides of the dehydration relative humidity and time, the dehydration temperature and light period were the main exterior factors that influenced on the dehydration tolerance of PLB.

Abstract:The accumulation and allocation of pollutants in 8 one-year-old tree speeies seedlings were studied, which were planted in ceramic industry polluted area for one and half years. The results showed that S, Cu and Pb pollutants of soil were serious, while Ni, Zn, Mn and Cr pollutants were slight. Total dry mass per plant had significant differences among 8 tree species with a range from 198 g to 3248 g, and the mean of 1187 g. The contents of S and Pb changed greatly among different tree species and organs. The contents of S, Cu and Pb in 8 tree species ranged of 325-12541, 0.3-19.2, and 0.1-11.0 μg g^-1, with the mean of 2459, 6.8, and 3.5 μg g^-1, respectively, while their accumulation per plant ranged of 485-7008, 1.2-23.7, and 0.6-6.8 mg, with the average of 2367, 8.0, and 2.9 mg, respectively. The S accumulation per plant was in order as F. altissima>T. championi>F. microcarpa>P. heterophyllum>A. dioica>G. robusta>F. microcarpa var. fuyuensis>G. axillaris; Cu: F. altissima>T. championi>F. microcarpa>G. robusta>P. heterophyllum>F. microcarpa var. fuyuensis>A. dioica>G. axillaris; Pb: F. microcarpa>G. robusta>T. championi>F. microcarpa var. fuyuensis>P. heterophyllum>F. altissima>G. axillaris>A. dioica. It suggested that F. altissima, T. championi and F. microcarpa were suitable for phytoremediation in ceramic industry polluted area.

Abstract:The stomatal and photosynthetic responses of four native ornamental species, such as Elaeocarpus sylvestris, Syzygium hainanense, Ficus microcarpa var. pusillifolia, and Cinnamomum philippinense grown in heavy traffic Dongguan Road were studied. The results showed that stomatal morphology had no difference among four species, while stomatal density of 4 species at Dongguan Road increased significantly, in which Elaeocarpus sylvestris increased most. The contents of chlorophyll and carotenoid of 4 species in Dongguan Road had different adaptive changes, but the variations were inconsistent. Except for C. philippinense, the maxium net photosynthesis rate (P_max) increased at Dongguan Road, but the changes of stomatal conductance and intercellular CO₂ concentration were inconsistent. The responses to auto-exhaust pollution were different among 4 species. Therefore, the 4 species adapted to traffic exhaust pollution by changing morphological characters and physiological properties.

Abstract:In order to select botanical herbicides to Bidens alba, aqueous extracts from the leaves of 12 species, which were reported with allelopathy or potential activity of weed inhibition, were used to spray Bidens alba seedlings. The results showed that all of the leaf aqueous extracts from 12 species had significant inhibition effects on the growth of Bidens alba seedlings (P<0.05) with synthetical effects (SE)≤-0.2. The inhibition strength was in order as: Eupatorium catarium>Ageratum conyzoides>Alocasia macrorrhiza>Solanum torvum>Lantana camara>Mikania micrantha>Broussonetia papyifera>Wedelia trilobata>Ipomoea triloba>Pueraria lobata>Paederia scandens>Ipomoea cairica. The 0.04 g DW mL^-1 aqueous extracts from the leaves of Eupatorium catarium could cause death of Bidens alba seedlings. The aqueous extracts from the stems of Eupatorium catarium and Ageratum conyzoides also had significant inhibition effects on the growth of Bidens alba seedlings (P<0.05), but which inhibition effects were lower than those from leaves. The analysis of regression showed that Bidens alba seedling growth negatively correlated with the concentration of aqueous extracts from the leaves of Eupatorium catarium (R²>0.85). The biomass of Bidens alba significantly decreased with increasing of the concentration of aqueous extracts. It suggested that Eupatorium catarium and Ageratum conyzoides could be used as natural botanical herbicide for Bidens alba due to their low concentration effect and wide availability.

Abstract:The effects of TMB-8, an intracellular calcium antagonist, on the pollen tube growth and cell wall construction in Pinus bungeana were investigated by means of fluorescence microscopy, laser scanning confocal microscopy, immunofluorescence technique and Fourier transform infra-red (FTIR) microspectroscopy. The results showed that TMB-8 inhibited P. bungeana pollen germination and tube growth in a dose-dependent manner. Normally growing pollen tubes displayed a typical tip-focused cytosolic free Ca²⁺ concentration gradient, while the Ca²⁺ concentration gradient dissipated in TMB-8-treated pollen tubes. Cellulose and callose were distributed uniformly in the wall of pollen tubes; acidic pectin was distributed in the tube wall except for the apex while esterified pectin was present only in the apex. In TMB-8-treated tubes, the content of cellulose, acidic pectin and callose increased while esterified pectin decreased in the apex compared with the normal tube wall. It indicated that the intracellular Ca²⁺ was necessary in the formation of apical cytosolic Ca²⁺ concentration gradient. Inhibition of intracellular Ca²⁺ release resulted in the arrest of pollen tube growth by the modification of cell wall composition in P. bungeana pollen tube.

Abstract:After examining the type material and comparing to some other species of Dyschoriste Nees and Strobilanthes Blume on pollen and flower morphology, it reveals that Dyschoriste sinica H. S. Lo is a member of Strobilanthes as S. sinica (H. S. Lo) Y. F. Deng. Strobilanthes sinica belongs to Championella group of Strobilanthes and is related to Strobilanthes japonica (Thunb.) Miq., but differs in its procumbent habits, oblong-elliptic, subsessile leaves and solitary flowers in leaf axils. The genus Dyschoriste is no longer distributed in China.

Abstract:In the field survey of "Fengshui Woods" in the nature reserves of Guangzhou, twenty-two species of vascular plants were newly recorded from Guangzhou for the first time, e.g. Microlepia hookeriana, Pteris grevilleana, Neolitsea confertifolia, Microdesmis caseariifolia, Rubus pluribracteatus, Maclura tricuspidata, and Hedyotis longipetala, et al.. The citation of specimens and distributions in Guangzhou are enumerated.

Abstract:XRN protein family, a kind of 5'-to-3'exoribonuclease,mainly participate in processes of pre-rRNAs and degradation of mRNAs, plays important role in the growth and development of animals, plants and microorganisms. The recent progresses of function of XRN family during plant developmental stages were reviewed. XRN family in plants involves in the processing of rRNA, miRNA pathway, degradation of exogenous mRNAs and ethylene signal pathway.