沙地彰武松与樟子松苗木抗旱生理特性比较

A Comparative Study on Physiological Characteristics of Drought Resistance of Pinus densiflora var. zhangwuensis and P. sylvestris var. mongolica in Sandy Soil

通过盆栽控水试验,对4年生彰武松、樟子松苗木在不同水分梯度下形态指标和叶片内丙二醛(MDA)、过氧化氢酶(CAT)、叶绿素(Chl)、脯氨酸(Pro)含量和叶片含水率(LWC)5项抗旱生理指标进行测定。结果表明:彰武松总干质量、根干质量、茎干质量和根茎比等4个指标都显著高于樟子松,而单片针叶面积显著小于樟子松,针叶厚度略大。在不同水分梯度下,彰武松的MDA含量都小于樟子松,CAT活性、Pro含量都高于樟子松。轻度干旱区〔(40%田间持水量(FMC)〕樟子松叶片中MDA,CAT和Pro含量较对照区(100%FMC)均呈现上升趋势,在中度干旱区(30%FMC)这3个指标继续明显升高,在重度干旱区(20%FMC)它们达到最大值;而轻度干旱区中彰武松叶片的这3个生理指标反而低于对照区,在中度干旱区它们才开始增大,尤其是CAT含量较对照区显著增加,这些指标也在重度干旱区中达到了最大值。这表明彰武松幼苗在更低的土壤含水率下才表现出胁迫伤害,并且在开始受到胁迫伤害时就迅速提高保护酶(CAT)活性,增加渗透调节物质含量(Pro),实现对干旱胁迫较强的忍耐性和较好的适应性。在不同水分梯度下,彰武松Chl含量和LWC均大于樟子松,这2个指标在同一树种中的变化趋势也相同,大小排序均为:对照区>轻度干旱区>中度干旱区>重度干旱区。

With a potting experiment,morphological parameters and five physiological indicators including malondialdehyde（MDA）,catalase（CAT）,chlorophyll（Chl）,proline（Pro）,and leaf water content（LWC） of the 4-year-old Pinus densiflora var.zhangwuensis and P.sylvestris var.mongolica were measured in different soil moisture gradient.The results showed that： P.densiflora var.zhangwuensis had significantly heavier total dry weight,dry weight of root,dry weight of stem and greater ratio of root and stem,had significantly smaller single needle area,and had slightly more thick needle than P.sylvestris var.mongolica.In different water gradient,P.densiflora var.zhangwuensis had lower MDA contents,and higher CAT and Pro contents than P.sylvestris var.mongolica.In mild drought area（40% FMC）,MDA,CAT and Pro contents of P.sylvestris var.mongolica had a ascending trend in comparison with those in control area（100% FMC）,and the three physiological indicators had a further increase in moderate drought area（30% FMC） and reached to the maximum in serious drought area（20% FMC）.By contrast in mild drought area these three physiological indicators in leaves of P.densiflora var.zhangwuensis were lower than those in control area,and began to increase in moderate drought area,especially the CAT content was significantly higher than that in control area,and they also reached to the maximum in serious drought area.The above results determinated that P.densiflora var.zhangwuensis showed stress symptoms at a lower soil moisture,and it could endure and adapt to drought stress by improving protective enzyme activity（CAT） and increasing osmotic substance（Pro）.At different moisture gradient,both Chl and LWC of P.densiflora var.zhangwuensis were more than those of P.sylvestris var.mongolica,and these two indicators in the same species had the same changing trend,which was ： CK mild drought area moderate drought area serious drought area.