State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, the Chinese Academy of Sciences, 20 Nanxincun, Xiangshan, Beijing, 100093, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
BMC Evol Biol. 2020 Oct 7;20(1):131. doi: 10.1186/s12862-020-01694-5.
Leaves have highly diverse morphologies. However, with an evolutionary history of approximately 200 million years, leaves of the pine family are relatively monotonous and often collectively called "needles", although they vary in length, width and cross-section shapes. It would be of great interest to determine whether Pinaceae leaves share similar morpho-physiological features and even consistent developmental and adaptive mechanisms.
Based on a detailed morpho-anatomical study of leaves from all 11 Pinaceae genera, we particularly investigated the expression patterns of adaxial-abaxial polarity genes in two types of leaves (needlelike and flattened) and compared their photosynthetic capacities. We found that the two types of leaves share conserved spatial patterning of vasculatures and genetic networks for adaxial-abaxial polarity, although they display different anatomical structures in the mesophyll tissue differentiation and distribution direction. In addition, the species with needlelike leaves exhibited better photosynthetic capacity than the species with flattened leaves.
Our study provides the first evidence for the existence of a conserved genetic module controlling adaxial-abaxial polarity in the development of different Pinaceae leaves.
叶片具有高度多样化的形态。然而，松科植物的叶片在进化史上已有大约 2 亿年的历史，相对较为单调，通常被统称为“针叶”，尽管它们在长度、宽度和横截面形状上有所不同。如果能确定松科植物的叶片是否具有相似的形态生理特征，甚至具有一致的发育和适应机制，那将是非常有趣的。
通过对松科 11 属植物的叶片进行详细的形态解剖学研究，我们特别研究了两类叶片（针叶和扁平叶）中背腹极性基因的表达模式，并比较了它们的光合能力。我们发现，这两种类型的叶片共享保守的维管束空间模式和背腹极性的遗传网络，尽管它们在叶肉组织分化和分布方向上表现出不同的解剖结构。此外，具有针叶的物种比具有扁平叶的物种表现出更好的光合能力。
我们的研究首次提供了证据，证明在不同松科叶片的发育过程中存在一个保守的控制背腹极性的遗传模块。
