盐胁迫对杨树形成层过氧化物酶活性及其效应的影响

研究了盐胁迫对杨树形成层中过氧化物酶(POD)活性和杨树次生木质部解剖特征的影响，结果表明，POD活性受盐胁迫影响在休眠期和生长期有不同的表现．处于休眠期的杨树，在较低的土壤含盐量下，随着含盐量的升高，POD活性呈现出先升高后降低的趋势，即含盐量0．024％→0．094％→0．145％，POD活性的变化83．7→132．1—63．2units·min^-1·g^-1FW；而生长期的杨树，POD活性受到盐胁迫的抑制而降低，当含盐量0．036％→0．289％逐步升高时，POD活性405．2→107．2units·min^-1·g^-1FW逐步降低．盐胁迫下杨树的解剖特征呈现规律性变化，当含盐量0．036％→0．125％→0．289％升高，早材和晚材导管直径变化分别为41．8→56．6→43．4μm和29．1→33．1→33．1μm；早材和晚材导管频率的变化分别为141．8→113．8→144．2个·mm^-2和160．0→134．8→206．7个·mm^-2．含盐量0．0365→0．289％升高，纤维长度和宽度的变化分别为693．8→570．4μm和14．9→13．5μm．

Impact of salt stress on peroxidase activity in Populus deltoides cambium and its consequence

Studies on the impact of salt stress on the peroxidase (POD) activity in Populus deltoides cambium and on the anatomic characteristics of its secondary xylem indicated that the changes of POD activity caused by soil salinity stress behaved differently in dormant and growing period. In low salinity soil, the POD activity of dormant Populus deltoides showed the trend of increasing first, and then, decreasing as the soil salinity was rising gradually. Namely, with the rising of soil salinity in the range of 0.024-->0.094-->0.145%, the POD activity varied in the range of 83.7-->132.1-->63.2 units.min-1.g-1FW accordingly. However, in growing season, with the gradual increase of soil salinity from 0.036 to 0.289%, the POD activity decreased gradually from 405.2 to 107.2 units.min-1.g-1FW. There were regular changes in wood anatomic characteristics of Populus deltoides. Namely, with the increase of soil salinity 0.036-->0.125-->0.289%, the vessel diameters (VD) of both early wood and late wood varied accordingly in the range of 41.8-->56.6-->43.4 microns, and 29.1-->33.1-->33.1 microns, respectively. The vessel frequencies (VF) were 141.8-->113.8-->144.2 and 160.0-->134.8-->206.7 entries mm-2, respectively. Along with the gradual increase of soil salinity from 0.036 to 0.289%, the fiber length gradually decreased from 693.8 to 570.4 microns, and the fiber width decreased from 14.9 to 13.5 microns.