低温胁迫下红松与西伯利亚红松光合与气孔特性

红松与西伯利亚红松均为寒温带著名的成林树种,具有较强的耐寒性,与红松相比,西伯利亚红松具有更强的耐寒性。为探究低温胁迫下两树种的生理响应机制及抗寒生理机理,本研究以5年生的红松与西伯利亚红松幼苗为材料,对其进行低温处理,3个胁迫温度(0℃、-20℃和-40℃)和3个胁迫时间(6、24和48 h),20℃为对照,研究低温胁迫下红松与西伯利亚红松的光合特性和气孔特性。T检验和方差分析结果表明,各光合指标和气孔密度在红松与西伯利亚红松中的差异显著(P<0.05),低温及低温胁迫时间对红松与西伯利亚红松各光合指标具有极显著影响(P<0.01),低温对红松与西伯利亚红松的气孔开度与气孔面积具有极显著影响(P<0.01)。胁迫前(20℃)和0℃低温胁迫下,红松中的净光合速率、气孔导度和蒸腾速率均显著高于西伯利亚红松,但在-20℃条件下胁迫6 h,西伯利亚红松各光合测定指标显著高于红松。随着温度的降低与胁迫时间的延长,两树种的各光合指标均呈下降趋势。红松中的气孔密度显著高于西伯利亚红松,胁迫前(20℃),红松与西伯利亚红松的气孔均为椭圆形,随着温度的降低,两树种的气孔开度和气孔面积显著减小。

Photosynthetic and Stomatal Characteristics of Pinus koraiensis and P.sibirica under Low Temperature Stress

Both Pinus koraiensis and P.sibirica with strong cold resistance are famous forest species in the cold temperate zone.Compared with P.koraiensis,P.sibirica has stronger cold resistance.In order to explore the physiological response and cold resistance mechanism of the two species under low temperature stress,5-yearold P.koraiensis and P.sibirica seedlings were used to be conducted by low temperature treatment.By setting three stress temperatures(0℃,-20℃ and-40℃)and three stress times(6,24 and 48 h),taking 20℃ as control,which were used to study the photosynthetic characteristics and stomatal characteristics of P.koraiensis and P.sibirica under low temperature stress.By t test and variance analysis,there were significant differences(P<0.05)between P.koraiensis and P.sibirica for each photosynthetic index and stomatal density,both low temperature and low temperature stress time had an extremely significant effect on each photosynthetic index of P.koraiensis and P.sibirica(P<0.01),and low temperature also had an extremely significant effect on stomatal opening size and stomatal area of P.koraiensis and P.sibirica(P<0.01).The net photosynthetic rate,stomatal conductance and transpiration rate in P.koraiensis were significantly higher than those in P.sibirica at 20℃(without stress)and 0℃(low temperature stress).However,under-20℃for 6 h,each photosynthetic index in P.sibirica was higher than that in P.koraiensis.With the decrease of temperature and the extension of stress time,each photosynthetic index of the two species showed a decreasing trend.The stomatal density in P.koraiensis was significantly higher than that in P.sibirica.Before stress(20℃),the stomas of P.koraiensis and P.sibirica were all oval.The stomatal opening size and stomatal area of the two species decreased significantly with the decrease of temperature.