热带睡莲展叶前后叶片形态结构差异与叶脐胎芽发育的关系

Relationship Between the Differences in Leaves Morphology and Structure and Epiphyllous Bud Development of Tropical Water Lily before and after Leaf Expansion

以热带胎生睡莲‘鲁比’(Nymphaea ‘Ruby’)和‘蓝鸟’(N.‘Blue Bird’)的胎生与非胎生叶片为材料,非胎生睡莲‘蓝星’(N.‘Colorata’)叶片为对照(CK),测定并比较3个品种的叶片形态特征参数,并采用石蜡切片技术观察卷叶期和展叶后的叶片解剖结构,旨在探讨热带睡莲叶片形态特征与胎芽发育的关系。结果表明:3个品种均具有典型的热带睡莲特征‘,鲁比’和‘蓝鸟’的胎生叶片除叶脐形成胎芽以外,叶长、叶宽和叶面积略低于非胎生叶片,但差异均不显著(P>0.05),而叶片解剖结构特征参数随着叶片的发育发生了改变。胎生睡莲展叶后叶片上、下表皮以及海绵组织厚度较卷叶期变薄,均高于非胎生叶片,而栅栏组织厚度、栅海比较卷叶期增加,且低于非胎生叶片,说明胎芽的发育导致栅栏组织结构紧密度降低,而海绵组织结构疏松度增加,但与叶片整体厚度无关;非胎生品种‘蓝星’叶片栅海比和细胞结构紧密度均显著高于胎生品种的叶片。各指标的可塑性变异较高,且存在一定的相关关系,具有明显的协同进化趋势。主成分分析显示,上下表皮厚度、海绵组织厚度、栅栏组织厚度、栅海比、叶片组织结构紧密度和疏松度均可视为反映睡莲胎生叶片解剖结构特征的主要指标。因此,胎生叶片通过改变叶肉组织结构的方式来响应胎萌的发生。

To explore the relationship between leaf morphological characteristics and epiphyllous bud development of tropical water lilies,the viviparous and non-viviparous leaves of Nymphaea‘Ruby’and N.‘Blue Bird’were used as materials,and the non-viviparous leaf of N.‘Colorata’was as control.The leaf morphological parameters of three cultivars were measured and compared,and the leaf anatomical structure during the leaf-rolling stage and leaf-expansion stage was observed using paraffin section.The results showed that all three cultivars had typical characteristics of tropical water lilies,the viviparous leaves of N.‘Ruby’and N.‘Blue Bird’,except for the epiphyllous bud,their leaf length,leaf width,and leaf area were slightly lower than non-viviparous leaves,but there were no significant differences(P>0.05),while the anatomical structural parameters of the leaves changed with the leaf development.Although the upper and lower epidermis,sponge tissue of the leaves of viviparous N.‘Ruby’and N.‘Blue Bird’were thinner at the leaf-expansion stage,both were higher than that of non-viviparous leaves.However,the palisade tissue and the ratio of palisade to sponge increased at the leaf-expansion stage,and were lower than that of non-viviparous leaves,indicating that the development of the viviparous buds resulted in a decrease in the structural compactness of the palisade tissue,while the looseness of sponge tissue structure increased,but it was not related to the leaf thickness.The ratio of palisade to sponge and cell structure compactness of the non-viviparous variety N.‘ Colorata’ were significantlyhigher than those of the viviparous variety N.‘ Ruby’. In addition, the plasticity variation of each indicator wasrelatively high, and there was a certain correlation and an obvious co-evolution. Principal component analysisshowed that the thickness of the upper and lower epidermis, spongy tissue, palisade tissue, the ratio of palisadeto spongy, and the compactness and looseness of the leaf tissue structure might be regarded as the mainindicators to reflect the anatomical structure characteristics of the viviparous leaves of water lilies. Viviparousleaves responded to epiphyllous bud development by changing the structure of mesophyll tissue.