Nakata P A, McConn M M
United States Department of Agriculture/Agricultural Research Service, Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, 1100 Bates Street, Houston, Texas 77030-2600, USA.
Plant Physiol. 2000 Nov;124(3):1097-104. doi: 10.1104/pp.124.3.1097.
Plants accumulate crystals of calcium oxalate in a variety of shapes, sizes, amounts, and spatial locations. How and why many plants form crystals of calcium oxalate remain largely unknown. To gain insight into the regulatory mechanisms of crystal formation and function, we have initiated a mutant screen to identify the genetic determinants. Leaves from a chemically mutagenized Medicago truncatula population were visually screened for alterations in calcium oxalate crystal formation. Seven different classes of calcium oxalate defective mutants were identified that exhibited alterations in crystal nucleation, morphology, distribution and/or amount. Genetic analysis suggested that crystal formation is a complex process involving more than seven loci. Phenotypic analysis of a mutant that lacks crystals, cod 5, did not reveal any difference in plant growth and development compared with controls. This finding brings into question the hypothesized roles of calcium oxalate formation in supporting tissue structure and in regulating excess tissue calcium.
植物会积累各种形状、大小、数量和空间位置的草酸钙晶体。许多植物如何以及为何形成草酸钙晶体在很大程度上仍然未知。为了深入了解晶体形成和功能的调控机制，我们启动了一个突变体筛选来鉴定遗传决定因素。对经化学诱变的蒺藜苜蓿群体的叶片进行目视筛选，以检测草酸钙晶体形成的变化。鉴定出了七类不同的草酸钙缺陷突变体，它们在晶体成核、形态、分布和/或数量上表现出变化。遗传分析表明，晶体形成是一个涉及七个以上基因座的复杂过程。对一个无晶体的突变体cod 5进行的表型分析显示，与对照相比，其植物生长和发育没有任何差异。这一发现使人们对草酸钙形成在支持组织结构和调节过量组织钙方面的假设作用产生了质疑。
