Grimmia and Racomitrium are two important genera of the family Grimmiaceae(Musci,Bryophyta).To predict and compare their potential distribution regions in relation to climatic conditions in China,and thereby help their conservation and subsequent field investigations,we modeled the geographical distribution at the genus level by using a maximum entropy algorithm modeling program(MaxEnt) based on 172 presence-only data for Grimmia and 181 data for Racomitrium,as well as 19 bioclimatic variables.We found Grimmia had higher habitat suitability in Zhejiang(0.7099,integrated habitat suitability index),Jiangsu(0.6212),Beijing(0.5987),Tianjin(0.5648),Yunnan(0.5532),Liaoning(0.5515),Taiwan(0.5422),Anhui(0.5398),and Jilin(0.4945),while Racomitrium had higher habitat suitability in Zhejiang(0.889),Shanghai(0.6564),Hong Kong(0.5897),Taiwan(0.5858),Guizhou(0.5354),Hubei(0.5039),Yunnan(0.4885),Chongqing(0.4871),Jiangsu(0.4793),and Anhui(0.4552).Comparison between the predicted distribution of Racomitrium and that of Grimmia showed that Racomitrium had higher distribution probability in Hong Kong,Chongqing,Guizhou,Guangdong,Guangxi,Hubei,Hainan,and Taiwan than Grimmia,-similar distribution probability to that of Grimmia in Jiangxi,Fujian,Hunan,and lower than Grimmia in the other provinces(municipality autonomous regions).Grimmia belonged to the typical moderate geographical element,mainly in the high altitude and cold districts.

Embryo sac development in Phaius tankervilliae(Aiton)Bl. was observed under transmission electron microscope.Three phases of functional megaspore and two phases of mature embryo sac were captured in this study.At the functional megaspore and 4-nucleate embryo sac stages,plasmodesmata were present between nucellar cells and embryo sac at the chalazal end.Plasmodesmata are cellular communicating junctions that link adjacent cells to form symplast of a plant.They provide a direct channel for material transport and signal transduction,therefore megagametogenesis is not at an absolutely insulated situation.A big vacuole was observed at the early stage of functional megaspore before it disappeared during the first mitotic division.However,many small vacuoles appeared at the interspaces of separating chromosomes.Distinct vacuoles were also observed in the synergid cells and egg cell during the early stage of mature embryo sac,but vanished when synergid cells degenerated.The change of vacuoles probably resulted from the cell physiological change.Our results may provide insights into reproductive biology of Phaius tankervilliae.

To investigate drought adaptation of evergreen and deciduous fig species occurring in dry karst forests , we compared anatomical traits , stem hydraulic conductivity , leaf water relation traits , photosynthesis , drought-resistance , and seasonal changes in physiology in evergreen Ficus orthoneura and deciduous F. pisocarpa , both of which belong to F. subgen. urostigma . Results showed that the two fig species have adapted to drought in different ways. Both have typical xeromorphic leaf structures , as shown by their two-layered palisade cells , highly-defused sponge cells and cystolith in leaves. They have a low cuticular evaporation ( g min ) and stomatal conductance ( g s ) to alleviate water loss. However , F. orthoneura posses- ses a xylem structure more resistant to cavitation and lower g min and adopts conserved water use to adapt to drought stress and maintains its leaves all year. In contrast , F. pisocarpa escapes from extreme drought stress by shedding leaves at the beginning of the dry season. To compensate the loss of carbon gain in the leafless period , F. pisocarpa has a particularly high rate in hydraulic and photosynthesis during the rainy season. The diversification of drought adaptation and water use reduces their compet ition for water and makes it possible for these

Container seedlings of three-year-old loquat were treated with Nitric oxide(NO) production inhibitors L-NAME,NaN3 and NO scavenger cPTIO to investigate the effects of endogenous NO and Jasmonate acid(JA) content on young loquat(Eriobotrya japonica cv.Zaozhong No.6) fruits under low temperature stress and determine the signal transduction relationship between endogenous NO and JA.Results showed that induced the endogenous NO and JA content of young loquat fruits to increase by low temperature stress.NO scavenger and NO production inhibitors treatment inhibited the activities of CAT,POD and SOD.Meanwhile,NO scavenger and NO production inhibitors treatment increased the contents of H2O2 and MDA in young loquat fruits under low temperature stress,which enhanced lipid peroxidation.The injury of young loquat fruits was aggravated by low temperature stress.NO scavenger and NO production inhibitors treatment decreased the activities of LOX and AOS in young loquat fruits under low temperature stress,and the pathway of JA biosynthesis was restrained.The endogenous JA content of young loquat fruits was closely related to the changes in endogenous NO content.There may be a signal cross between NO and JA in response to low temperature stress in young loquat fruits.

The essential oil of golden pomelo(Citrus grandis Osbeck cv.) peel was extracted by both steam distillation-extraction and organic solvent extraction.The concentrated extracts were analyzed by capillary gas chromatography-mass spectrometry.In addition,the essentia-loil components extracted from the two methods were compared.Fifteen components were identified in steam distillation-extraction,representing 99.01% of the total peak area,and se-venteen components in solvent extraction,representing 97.55% of the total peak area.Of the six in common components for the two extracts,limonene was the dominant constituent,so the golden pomelo peel produced in Meizhou can be used as an important resource for limonene.In addition,9,12-tetracyclo-octadiene-acid(0.62%),ostholein(0.5%) and sitosterol(0.5%) were also found in the sample extracted by solvent extraction,and those relative contents were higher than other components.Among these components,cnidium lactone is known for its anti-osteoporosis,anti-virus and other pharmacological activities,and sitosterol can decrease serum cholesterol.