ABSTRACT

The drought tolerance trait osmotic adjustment has been widely studied in annual crops but has received little attention in perennial forages. White clover (Trifolium repens L.) is a forage legume of major importance with a reputation for drought susceptibility. This paper we believe is the first to publish research which measures intraspecific variability for osmotic adjustment within this species. This preliminary study identified variation for osmotic adjustment with the aim of providing sources of the trait for incorporation into new cultivars to improve drought tolerance. The research was conducted using a group of 5 cultivars which represented most of the morphological variation of the species. Plants of similar maturity and leaf area that were 18 months of age were subjected to a drying cycle in a glasshouse. Plant water relations were defined by measurements of water potential, osmotic potential and relative water content with these undertaken on a daily time-step. Substantial variation in the level of osmotic adjustment was observed with Kent Wild White and Siral the two cultivars with the greatest expression (0.5 and 0.46 MPa, respectively). These levels of expression of osmotic adjustment in white clover are comparable to those observed in annual legume crop species.

摘要

耐旱性状渗透调节已在一年生作物中得到广泛研究，但在多年生牧草中很少受到关注。白三叶草L.) 是一种具有干旱敏感性的重要牧草豆类。我们认为这篇论文是第一篇发表研究，该研究测量了该物种内渗透调节的种内变异性。这项初步研究确定了渗透调节的变异，目的是提供该性状的来源，以将其纳入新品种以提高耐旱性。该研究是使用一组 5 个品种进行的，这些品种代表了该物种的大部分形态变异。18 个月大的具有相似成熟度和叶面积的植物在温室中进行干燥循环。植物水分关系是通过测量水势、渗透势和相对水含量来定义的，这些测量是在每天的时间步长上进行的。用 Kent Wild White 和 Siral 观察到渗透调节水平的显着变化，这两个品种表达量最大（分别为 0.5 和 0.46 MPa）。白三叶中渗透调节的这些表达水平与一年生豆科作物物种中观察到的水平相当。