Study On Vestured Pits On Secondary Xylem In A Few Elaeocarpaceae Garden Plants

Wood samples of 7 species that belong to family Elaeocarpaceae, genera Elaeocarpus and Sloanea were collected every month or every two months. Standard methods were used to prepare the wood slices which were treated by the different chemical reagents (20% 20% sodium hypochlorite,1:1 hydrogen peroxide and glacial acetic acid)to observe the structure in vessel– vessel and vessel-ray parenchyma pits by SEM. By comparison with 2 Leguminosae species that have characterized by numerous vestured pits, the distribution and morphological features of vestured pits in 7 species of family Elaeocarpaceae were surveyed in details. Ratio of vestured pits in 7 species in every collection were measured to correlated with contents of starch grains of corresponding twigs in every collection by means of regression analysis.The results of this study are as follows:1. Whether the samples were treated by chemical reagents or not , SEM illustrates that vestures were present in all species studied ,although the morphology and distribution of vestured pits varied greatly. Vestures occur in inner or outer pit apertures and pit chambers to form vestered pits and also on vessel walls or helical thickenings. The morphological features of vestures vary considerably. Most vestures occurring in inner or outer pit apertures are forked or tooth-like vestures or massive foliate vestures,occasionally filamentous vestures. Most vestures in pit chambers are massive foliate vestures,occasionally silk-shaped or forked or tooth-like vestures. Most vestures on vessel walls and helical thickenings are dot-shaped or conical vestures,occasionally forked or rod-shaped vestures.2. There are a few changes in morphology of vestured pits after treatment by 20% sodium hypochlorite,the morphology became more obvious and the distribution of vestured pits after treatment by 20% sodium hypochlorite is similar to that of untreatment.There are a lot changes in morphology and distribution of vestured pits after treatment by segregation liquid. the morphology becomes more fuzzy, many sample previously found vestured pits,Many vestured pits disappeared after treatment by segregation liquid while vestred pits occurred without treatment by segregation liquid. The vestured pits become less obvious,less uneven and less regular in distribution after treatment by segregation liquid.3. Through the regression analysis between vestured pits rate and starch content in 7 species of family Elaeocarpaceae,the vestured pits rate and starch content of E.serratus have linear correlation(y = -3.5524x + 16.078,R~2 = 0.5196,R≈0.72), the vestured pits rate and starch content of E.japonicus treated by 20% sodium hypochlorite have linear correlation(y = -3.5524x + 16.078,R~2 = 0.5196,R≈0.72);the vestured pits rate and Starch content of pongamia pinnata have binomial correlation(y = -4.8394x~2 + 26.806x + 64.377,R~2 = 0.7511,R≈0.86). There are no correlation between vestured pits rate and starch content in the rest of plants whether the samples were treated by chemical reagents or not.4. Vestured pits occurred in 7 Elaeocarpaceae species. However compared to number of vestured pits in leguminosae species,that in Elaeocarpaceae species is less. Therefore application of Elaeocarpaceae species in landscape need consider their ability of drought resistance in that vestured pits relative to drought resistance.