摘要
为探究外源钙缓解干旱胁迫对白枪杆(Fraxinus malacophylla)幼苗叶片光合色素及叶片解剖结构的伤害机制,本研究以两年生白枪杆幼苗为材料,采用双因素完全随机区组试验,测定白枪杆幼苗叶片性状及光合色素.因素1为正常水平(80±5)％、轻度干旱(65±5)％、中度干旱(50±5)％和重度干旱(35±5)％;因素2为0、25、50和75 mmol·L-1外源CaCl.结果表明,同一干旱时期,白枪杆幼苗叶片性状以及光合色素叶绿素a、叶绿素b与叶绿素(a+b)含量、叶片厚度、上下表皮厚度、栅海组织厚度均随钙浓度的增加呈先上升后下降的变化规律,且25 mmol·L-1钙处理缓解效果最佳;在正常水分与轻度干旱时期,叶绿素a/b值随着钙浓度的增加呈"V"型变化.同一钙浓度下,白枪杆幼苗叶片性状、光合色素含量及叶片厚度及栅海组织厚度等随干旱程度的加深呈显著下降趋势,施加25和50mmol·L-1钙有效提高白枪杆幼苗的抗旱性.相关分析表明,叶片性状、光合色素含量和叶片厚度、栅海组织厚度等呈极显著正相关关系.
Abstract
To investigate the damage mechanism of exogenous calcium in alleviating drought stress on the photosynthetic pigments and leaf anatomical structure of Fraxinus malacophylla seedlings.In the present study,a two-factor completely randomized block test was conducted using 2-year-old F.malacophylla seedlings,with factor 1 being the degree of drought with four drought levels,normal(80±5)％,mild drought(65±5)％,moderate drought(50±5)％,and severe drought(35±5)％,and factor 2 beings exogenous CaCl2 with four levels(0,25,50,and 75 mmol·L-1).Measure the leaf characteristics and photosynthetic pigments of F.malacophylla seedlings,and use the bare handed and paraffin sectioning methods to measure the thickness of the upper and lower epidermis,leaf thickness,and the thickness of the palisade tissue of the leaves.The results showed that during the same drought period,the leaf traits,photosynthetic pigments[chlorophyll a,chlorophyll b,and chlorophyll(a+b)],leaf thickness,upper and lower epidermal thickness,and palisade tissue thickness of F.malacophylla seedlings all showed an increasing trend followed by a decreasing trend with the increase of calcium concentration,and the best relief effect was achieved with a treatment of 25 mmol·L-1.During normal water and mild drought periods,the chlorophyll a/b value chang-es in a"V"shape with increasing calcium concentration.Under the same calcium concentration,the leaf traits,photosynthetic pigments,leaf thickness,and palisade tissue thickness of F.malacophylla seedlings showed a significant downward trend with the deepening of drought severity.Applying 25 and 50 mmol·L-1 calcium effectively improved the drought resistance of F.malacophylla seedlings.The correlation analysis showed that there was a highly significant positive correlation between leaf traits,photosynthetic pig-ments,leaf thickness,and palisade tissue thickness.
基金项目
云南省"三区"科技人才支持计划(990023236)
云南省教育厅科学研究基金项目(2021J0166)
西南林业大学基金(2023YY013)
NETL
NSTL
万方数据