棉纤维发育相关酶活性的基因型差异与纤维比强度的关系

 【目的】以纤维比强度差异较大的不同基因型棉花为材料，研究它们纤维发育过程中相关酶活性的动态变化与纤维比强度的关系，为探索改善棉纤维比强度的生理调控途径提供理论依据。【方法】选择棉纤维比强度分属高（科棉1号）、中（美棉33B）、低（德夏棉1号和苏棉15号）3种类型，4个不同基因型的品种，在大田栽培条件下，研究棉纤维次生壁加厚过程中相关酶活性的动态变化、纤维素累积和纤维比强度形成的关系。【结果】β-1,3-葡聚糖酶活性在次生壁加厚发育过程中呈下降趋势，蔗糖合成酶、过氧化物酶和IAA氧化酶活性变化均呈单峰曲线，基因型间差异主要表现在酶活性的大小和峰值出现的时间。科棉1号属高强纤维基因型，棉纤维中与纤维发育相关的酶活性在整个次生壁加厚期高于中、低强纤维基因型，前者酶活的动态变化与纤维素累积快速增长期的协调性好，纤维素累积平缓，纤维比强度增强的幅度大；反之，如低强纤维品种德夏棉1号和苏棉15号，其纤维发育相关酶在次生壁加厚期活性低，纤维素累积快速增长期短，纤维比强度增强的幅度小；美棉33B棉纤维发育相关酶活性、纤维素累积和纤维比强度形成特征介于上述两种基因型之间。【结论】不同基因型棉花纤维中与纤维发育相关的酶活性存在显著差异，该差异可能是导致纤维素累积特性及纤维比强度形成基因型间差异的主要生理原因之一。

Fiber Strength and Enzyme Activities of Different Cotton Genotypes During Fiber Development

Abstract: 【Objective】To study the dynamics of enzyme activities, which play important roles during cotton fiber development, and its relationship with fiber strength, and provide studying basis for the ways of physiological adjusting to improve fiber strength, 【Method】field experiments were carried out in Nanjing, Jiangsu Province (the Yangtze River region in China) in 2004 and 2005 by choosing three genotype cottons with significant differences in fiber strength as materials. The study focused on the time course of sucrose synthetase, β-1,3-glucanase, peroxidase and IAA oxidase activities during the secondary wall thickening in cotton fiber. The boll samples were collected from the first and second fruiting positions of 6 to 8 sympodial branchs. 【Result】The results showed that β-1,3-glucanase activity continuously decreased during the secondary wall thickening in cotton fiber. The activity curves of other enzymes (sucrose synthetase, peroxidase and IAA oxidase) were all unimodal and they might have a certain synergistic effect during fiber thickening development. However, there were obviously differences among three genotypes in the levels of enzyme activities and occurrence time of the peak. The cultivar (Kemian 1), which produced high strength fiber, had higher peak value of the related enzyme (sucrose synthetase, β-1,3-glucanase, peroxidase and IAA oxidase) activities, and slower descend trend subsequently. These resulted in a longer and more tempered cellulose accumulation, and in the wider range and longer period of fiber strength increase. While the cultivars (Dexiamian 1 and Sumian 15), which produced lower strength fibers, the items were just the contrary. And the cultivar (NuCOTN 33B), which produced medium strength fiber, the items were intervenient.【Conclusion】There are significant differences in the related enzymes activities among different genotypes. And that may be one of important factors which lead to the great difference in the characteristics of cellulose accumulation and the fiber strength formation in different genotype cottons.