臭氧对黄檗幼苗叶片可见伤害及气孔特征的影响

以4年生黄檗(Phellodendron amurense Rupr.)幼苗为试验材料,利用开顶箱(OTCs)模拟法,设置了4个处理(O3摩尔分数为40×10-9(对照)、60×10-9、80×10-9和120×10-9)的气体熏蒸试验,观测了不同摩尔分数臭氧对黄檗叶片的可见伤害及叶片气孔结构特征的影响。结果表明:单叶伤害面积比和单株叶可见伤害比随O3摩尔分数升高而增加(P0.01),摩尔分数为120×10-9下熏蒸6 d时黄檗叶片出现坏死斑等伤害症状。O3摩尔分数为80×10-9和120×10-9处理组下表皮气孔密度极显著增加(P0.01),分别增加37.26%和35.12%,两处理组间差异不显著。气孔宽度、开度、周长和面积也均极显著降低(P0.01)。而O3摩尔分数为60×10-9时除气孔宽度和开度降低外,其他参数变化不显著(P0.05)。气孔比随O3摩尔分数升高而增大,并在80×10-9时达到最大为3.52,随后降低。黄檗叶片气孔大小参数与O3摩尔分数之间的相关性可用一元二次曲线方程较好地描述。推测摩尔分数为(80±10)×10-9时是黄檗幼苗臭氧胁迫忍耐性的临界点。

Effects of High O3 Concentration on Foliar Visible Injury and Stomata Characteristics of Phellodendron amurense Rupr.Seedling Leaves

With four-year-old Phellodendron amurense Rupr.seedlings exposed to four levels (40 (control), 60, 80 and 120 nmol· mol-1) of O3 concentrations in open-top chambers(OTCs), we studied the effects of high O3 concentrations on foli-ar visible injury and stomata characteristics on leaves of P.amurense Rupr.seedlings.Compared to control, the leaves of P. amurense showed necrotic spots induced by high O3 concentrations, and the percentage of visible foliar injury per leaf was significantly higher (P<0.01).The stomatal density on lower epidermis (SD) were significantly increased (P<0.01) by 37.26%and 35.12%under O3 concentration of 80, 120 nmol· mol-1 , respectively, with no significant difference between these two treatments.The stomatal perimeters, areas, widths and stomatal aperture were significantly decreased ( P<0.01) among above three treatments.Through the stomatal width and the opening degree reduced significantly under 60 nmol· mol-1 , other parameters showed no significant difference ( P>0.05) .Stomatal ratio increased along with elevated O3 con-centration and got to the maximum of 3.52 under 80 nmol· mol-1 , then reduced till it increased to 120 nmol· mol-1 .Cor-relation between parameters of stomatal size in leaves of P.amurense and O3 concentrations was expressed with unary quad-ratic curve equation.Therefore, (80±10)nmol· mol-1 would be the critical point of ozone stress tolerance in P.amurense.