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在我国南北气候过渡地区,采用遮阴试验和石蜡切片法,研究越冬期不同光强对3个不同秋眠型紫花苜蓿(Medicago sativa)品种(‘维多利亚’、‘巨人201’和‘游客’)叶片解剖结构的影响。结果表明:随着光强减弱,各紫花苜蓿品种表皮结构中上、下表皮角质层厚度,气孔密度和气孔开度明显下降;上、下表皮厚度呈上升趋势。随着遮阴强度增加,叶肉组织中海绵组织细胞宽度显著上升,栅栏组织厚度、栅栏组织细胞层数、栅栏组织厚度/海绵组织厚度显著下降;品种间海绵组织厚度和栅栏组织细胞宽度变化趋势不一致。叶片结构整体特征中叶片厚度、叶肉厚度、中脉厚度、组织结构紧密度随光强减弱而显著下降,组织结构疏松度明显上升,叶脉突起度变化不明显。品种间各叶片解剖性状变幅及可塑性指数具有明显的差异,表明其对弱光适应方式不同。Pearson相关分析表明,各紫花苜蓿品种叶片气孔密度、栅栏组织厚度、叶肉厚度、叶片厚度及栅栏组织厚度/海绵组织厚度与光强呈显著正相关,可能是紫花苜蓿叶片解剖结构光强敏感特征参数,其中,‘维多利亚’叶片敏感特征参数与光强相关程度较低,与光强相关的性状较少。综合各项分析结果,初步确定越冬期紫花苜蓿耐阴性与其秋眠性相关,半秋眠型品种‘维多利亚’>秋眠型品种‘巨人201’≥非秋眠型品种‘游客’。
In the climatic transitional regions of north and south of our country, shading test and paraffin section method were used to study the effect of different light intensities during winter period on three different Medicago sativa cultivars (’Victoria’, ’Giants201’ and ’Tourists’) Effect of leaf anatomy. The results showed that with the decrease of light intensity, the stratum corneum thickness, stomatal density and stomatal opening in the epidermis of all the alfalfa cultivars decreased significantly; the thickness of the upper and lower epidermis tended to increase. With the increase of shading intensity, the cell width of sponge tissue in mesophyll increased significantly, the thickness of palisade tissue, the number of palisade tissue cell layer and the thickness of palisade tissue / sponge tissue decreased significantly. The variation trend of sponge tissue thickness and palisade cell width was not consistent . Leaf thickness, mesophyll thickness, midrib thickness and tissue structure density decreased significantly with the decrease of light intensity. The porosity of tissue structure increased obviously, and the change of vein protrusion degree was not obvious. The variation of anatomic traits and the plasticity index of all leaves showed obvious differences, which indicated that they had different adaptation to low light. Pearson correlation analysis showed that leaf stomatal density, palisade tissue thickness, leaf thickness, leaf thickness and palisade tissue thickness / spongy tissue thickness and light intensity were significantly and positively correlated with each other, which may be the characteristic parameters of light intensity of alfalfa leaf anatomy Among them, the sensitive characteristic parameters of ’Victoria’ leaf had less correlation with light intensity and less light intensity related traits. Based on the results of the analysis, the negative tolerance of alfalfa overwintering was correlated with its fall dormancy. The semi-fall dormant variety ’Victoria’> Fall dormant variety ’Giant 201’≥ non-fall dormant variety’ tourists’.