Rascio Agata, Rascio Nicoletta, Rinaldi Michele, Valentini Massimiliano
Consiglio per la Ricerca e la Sperimentazione in Agricoltura, Centro di Ricerca per la Cerealicoltura S.S. 673 Km 25,200, 71122 Foggia, Italy.
Dipartimento di Biologia, Università degli Studi di Padova, viale Colombo 3, 35121 Padova, Italy.
Physiol Plant. 2015 Jun;154(2):210-22. doi: 10.1111/ppl.12280. Epub 2014 Oct 28.
A wheat (Triticum turgidum subsp. durum) mutant, generated with sodium azide from wild-type (WT) cv. 'Trinakria', differs in its water affinity of dry leaves, and was designated as a water-mutant. Compared with the WT, water-mutant leaves have lower rates of water uptake, while stomatal and cuticular transpiration do not differ. The nuclear magnetic resonance proton signals used for image reconstruction of leaf cross sections showed differences between these genotypes for the T1 proton spin-density and the T2 proton spin-spin relaxation time. Structural and histochemical analyses at midrib level showed that the water-mutant has thinner leaves, with more and smaller cells per unit area of mesophyll and sclerenchyma, and has altered staining patterns of lignin and pectin-like substances. Stress-strain curves to examine the rheological properties of the leaves showed a biphasic trend, which reveals that the tensile strength at break load and the elastic modulus of the second phase of the water-mutant are significantly higher than for the WT. These data support the proposal of interrelationships among local biophysical properties of the leaf, the microscopic water structure, the rheological properties and the water flux rate across the leaf. This water-mutant can be used for analysis of the genetic basis of these differences, and for identification of gene(s) that govern these traits.
用叠氮化钠从野生型（WT）“Trinakria”品种培育出的一个小麦（硬质小麦亚种）突变体，其干叶的水分亲和力有所不同，被指定为水分突变体。与野生型相比，水分突变体叶片的水分吸收速率较低，而气孔蒸腾和角质蒸腾没有差异。用于叶片横截面图像重建的核磁共振质子信号显示，这些基因型在T1质子自旋密度和T2质子自旋 - 自旋弛豫时间方面存在差异。中脉水平的结构和组织化学分析表明，水分突变体的叶片更薄，叶肉和厚壁组织单位面积内的细胞更多且更小，并且木质素和果胶类物质的染色模式发生了改变。用于检测叶片流变特性的应力 - 应变曲线呈现双相趋势，这表明水分突变体在断裂载荷下的拉伸强度和第二阶段的弹性模量显著高于野生型。这些数据支持了叶片局部生物物理特性、微观水结构、流变特性和叶片水分通量率之间存在相互关系的观点。这个水分突变体可用于分析这些差异的遗传基础，以及鉴定控制这些性状的基因。
