Department of Biology, McGill University, 1205 Avenue Docteur Penfield, Montréal, QC, Canada H3A 1B1.
Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montréal, QC, Canada H3A 0C3.
J R Soc Interface. 2019 Oct 31;16(159):20190454. doi: 10.1098/rsif.2019.0454. Epub 2019 Oct 30.
Upon hydration and dehydration, the vegetative tissue of can reversibly swell and shrink to generate complex morphological transformations. Here, we investigate how structural and compositional properties at tissue and cell wall levels in lead to different stem curling profiles between inner and outer stems. Our results show that directional bending in both stem types is associated with cross-sectional gradients of tissue density, cell orientation and secondary cell wall composition between adaxial and abaxial stem sides. In inner stems, longitudinal gradients of cell wall thickness and composition affect tip-to-base tissue swelling and shrinking, allowing for more complex curling as compared to outer stems. Together, these features yield three-dimensional functional gradients that allow the plant to reproducibly deform in predetermined patterns that vary depending on the stem type. This study is the first to demonstrate functional gradients at different hierarchical levels combining to operate in a three-dimensional context.
在水合和脱水过程中， 的营养组织能够可逆地膨胀和收缩，从而产生复杂的形态转变。在这里，我们研究了 组织和细胞壁水平的结构和组成特性如何导致内茎和外茎之间不同的茎卷曲形态。我们的结果表明，两种茎类型的定向弯曲都与茎的腹侧和背侧之间的组织密度、细胞取向和次生细胞壁组成的横截面梯度有关。在内茎中，细胞壁厚度和组成的纵向梯度会影响顶端到基部的组织膨胀和收缩，从而使茎能够比外茎更复杂地卷曲。总之，这些特征产生了三维功能梯度，使植物能够以可重复的方式在预定的模式中变形，这些模式因茎的类型而异。这项研究首次证明了不同层次的功能梯度结合在一起，在三维环境中起作用。
