Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Corps, Shihezi University, Shihezi, P.R. China.
School of Natural Sciences, Faculty of Science and Engineering, Macquarie University, North Ryde, NSW, Australia.
Ann Bot. 2022 Sep 6;130(2):231-243. doi: 10.1093/aob/mcac086.
The process of domestication has driven dramatic shifts in plant functional traits, including leaf mass per area (LMA). It remains unclear whether domestication has produced concerted shifts in the lower-level anatomical traits that underpin LMA and how these traits in turn affect photosynthesis.
In this study we investigated controls of LMA and leaf gas exchange by leaf anatomical properties at the cellular, tissue and whole-leaf levels, comparing 26 wild and 31 domesticated genotypes of cotton (Gossypium).
As expected, domesticated plants expressed lower LMA, higher photosynthesis and higher stomatal conductance, suggesting a shift towards the 'faster' end of the leaf economics spectrum. At whole-leaf level, variation in LMA was predominantly determined by leaf density (LD) both in wild and domesticated genotypes. At tissue level, higher leaf volume per area (Vleaf) in domesticated genotypes was driven by a simultaneous increase in the volume of epidermal, mesophyll and vascular bundle tissue and airspace, while lower LD resulted from a lower volume of palisade tissue and vascular bundles (which are of high density), paired with a greater volume of epidermis and airspace, which are of low density. The volume of spongy mesophyll exerted direct control on photosynthesis in domesticated genotypes but only indirect control in wild genotypes. At cellular level, a shift to larger but less numerous cells with thinner cell walls underpinned a lower proportion of cell wall mass, and thus a reduction in LD.
Taken together, cotton domestication has triggered synergistic shifts in the underlying determinants of LMA but also photosynthesis, at cell, tissue and whole-leaf levels, resulting in a marked shift in plant ecological strategy.
驯化过程导致植物功能性状发生了剧烈变化，包括叶面积比（LMA）。目前尚不清楚驯化是否导致了支撑 LMA 的较低层次解剖结构特征的协同变化，以及这些特征反过来如何影响光合作用。
在这项研究中，我们通过细胞、组织和整叶水平的叶片解剖结构特性，研究了 LMA 和叶片气体交换的控制因素，比较了 26 个野生和 31 个棉花（Gossypium）驯化基因型。
正如预期的那样，驯化植物表现出较低的 LMA、较高的光合作用和较高的气孔导度，这表明它们向叶片经济谱的“更快”端转移。在整叶水平上，野生和驯化基因型的 LMA 变异主要由叶片密度（LD）决定。在组织水平上，驯化基因型中较高的叶面积比（Vleaf）是由表皮、叶肉和维管束组织和气腔体积的同时增加驱动的，而较低的 LD 则是由于栅栏组织和维管束（密度较高）的体积减小，同时表皮和气腔（密度较低）的体积增大。海绵叶肉的体积对驯化基因型中的光合作用具有直接控制作用，但对野生基因型中的光合作用只有间接控制作用。在细胞水平上，向更大但数量较少的细胞壁较薄的细胞的转变，支撑着细胞壁质量的比例降低，因此 LD 降低。
总的来说，棉花驯化导致了 LMA 以及光合作用的潜在决定因素的协同变化，在细胞、组织和整叶水平上，导致植物生态策略的显著转变。
