Diffusion of volatile organics and water in the epicuticular waxes of petunia petal epidermal cells
Diffusion of volatile organics and water in the epicuticular waxes of petunia petal epidermal cells
复制标题
矮牵牛花瓣表皮细胞表皮蜡质中挥发性有机物和水的扩散
DOI：
10.1111/tpj.15693
复制
发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Morgan, John A.
中科院分区：
文献类型：
--
作者：
Ray, Shaunak;Savoie, Brett M.;Dudareva, Natalia;Morgan, John A.
植物蜡是结晶和无定形蜡的混合物，限制植物和大气之间的分子交换。表皮蜡的多组分性质使得物理性质和运输性质之间的关系的研究变得复杂。在这里，一个模型角质层的基础上的epicuticular蜡ofPetunia hybridflower花瓣制定测试的影响，蜡的组成对水和挥发性有机化合物（VOCs）的扩散。模型表皮由二十四烷（C24 H50）、1-二十二烷醇（C22 H45 OH）和3-甲基丁基十二烷酸酯（C17 H34 O2）组成，反映了天然蜡的相对链长、官能团、分子排列和结晶度。进行分子动力学模拟，以获得通过不同组成的蜡移动的化合物的扩散系数。模拟VOC扩散系数的模型系统被发现在隔离矮牵牛cuprium的vitromeasurements高度相关。VOC扩散率在完全无定形蜡中增加了30倍，表明结晶度对表皮渗透性有显著影响。蜡的结晶度高度依赖于晶格长度的延长和晶胞之间间隙宽度的减小。水和高分子量的挥发性有机化合物的扩散显着影响的晶体间距和长度的变化，而低分子量的挥发性有机化合物的影响较小。从原子模拟和排放量从矮牵牛花测得的扩散系数的比较表明，植物角质层中的VOC排放网络的作用是由于差分控制个别挥发性有机化合物的传质控制的组成，数量和动态的气味排放。
Plant cuticles are a mixture of crystalline and amorphous waxes that restrict the exchange of molecules between the plant and the atmosphere. The multicomponent nature of cuticular waxes complicates the study of the relationship between the physical and transport properties. Here, a model cuticle based on the epicuticular waxes ofPetunia hybridaflower petals was formulated to test the effect of wax composition on diffusion of water and volatile organic compounds (VOCs). The model cuticle was composed of ann‐tetracosane (C24H50), 1‐docosanol (C22H45OH), and 3‐methylbutyl dodecanoate (C17H34O2), reflecting the relative chain length, functional groups, molecular arrangements, and crystallinity of the natural waxes. Molecular dynamics simulations were performed to obtain diffusion coefficients for compounds moving through waxes of varying composition. Simulated VOC diffusivities of the model system were found to highly correlate within vitromeasurements in isolated petunia cuticles. VOC diffusivity increased up to 30‐fold in completely amorphous waxes, indicating a significant effect of crystallinity on cuticular permeability. The crystallinity of the waxes was highly dependent on the elongation of the lattice length and decrease in gap width between crystalline unit cells. Diffusion of water and higher molecular weight VOCs were significantly affected by alterations in crystalline spacing and lengths, whereas the low molecular weight VOCs were less affected. Comparison of measured diffusion coefficients from atomistic simulations and emissions from petunia flowers indicates that the role of the plant cuticle in the VOC emission network is attributed to the differential control on mass transfer of individual VOCs by controlling the composition, amount, and dynamics of scent emission.