Abstract:

This paper dealed with anatomical characteristics of Poplar[Populus deltoides(LUX)] which was the mainly cultivated species of coastal shelterbelt in Jiangsu Province. It gived a detail description of the general characteristics of the constitutions of the secondary xylem of the plant, and measured 16 major quantitative characteristics of secondary xylem of Poplar, including annual ring width(ARW)、vessel length(VL)、vessel area of early wood and late wood( VA )、vessel perimeter of early wood and late wood (VP)、vessel diameter of early wood and late wood (VD)、percentage of solitary vessels of early wood and late wood(PSV)、vessel frequency of early wood and late wood(VF)、fiber length(FL)、fiber width(FW)、ray height(RH) and ray frequency(RF). The results indicated that, under stress of different soil salinity: (1) There was no evident variation to morphological characteristics of secondary xylem structure of Poplar in which its constitutional molecule was becoming smaller. (2) There was evident variation to quantitative characteristics of secondary xylem structure of Poplar, namely, with the gradually increasing of soil salinity 0.036%→0.289%,ARW declined 0.91→0.77μm,VL 367.6→341.5μm,FL and FW 693.8→570.4μm and 14.9→13.5μm,respectively, RH and RF changed 284.3→249.2μm and 58.9→75.5mm^-2 ,respectively. All the changes of the characters showed the growth of Poplar was restrained. With the gradually increasing of soil salinity 0.036%→0.289%,VA rised 1 575.6→1 703.6μm² and 760.1→947.7μm² in early wood and late wood, respectively, VP 167.7→195.1μm and 120.8 →143.7μm,respectively, VD 41.8→43.4μm and 29.1→33.1μm,respectively, VF 141.8→144.2mm^-2 and 160→206.7mm^-2 , respectively,PSV declined 65.9%→30.5% and 59.4%→40.8% in early wood and late wood, respectively. These changes demonstrated that the vessel shortened and widened appearing the grouping distribution under stress of soil salinity, and that both efficiency and safety of water transportation of vessel were improved.

Key words: Soil salinity stress, Populus deltoides(LUX), Anatomical characteritics, Secondary xylem, Quantitative characteristics