盐胁迫下施钾调节棉纤维断裂比强度的糖代谢机制

The mechanism of sucrose metabolism of potassium regulating the cotton fiber strength under salt stress

【目的】研究盐胁迫下施钾调节棉花纤维断裂比强度的糖代谢机制,为盐碱地适量施钾提供理论依据。【方法】以中棉所79(耐盐型)和泗棉3号(盐敏感型)为试验材料,通过设置3个土壤电导率(低盐1.68~1.78 dS·m^-1、中盐6.21~6.42 dS·m^-1、高盐10.59~11.08 dS·m^-1),3个施钾量(0、150、300 kg·hm-2),研究了盐胁迫下施钾对棉花纤维断裂比强度、纤维加厚发育期纤维素累积和蔗糖、β-1,3-葡聚糖及相关酶活性的影响。【结果】(1)盐胁迫显著降低了棉花纤维断裂比强度;施钾显著缓解了中、高盐胁迫下盐分对纤维断裂比强度的影响,但施钾150、300 kg·hm^-2处理间无显著差异。盐碱地施钾,中棉所79的纤维断裂比强度增幅高于泗棉3号。(2)盐胁迫降低了纤维加厚期纤维素的累积量,降低了纤维蔗糖含量并提高了β-1,3-葡聚糖含量;盐碱地施钾则提高了纤维加厚发育期纤维素最大累积速率,提高了花后28 d磷酸蔗糖合成酶以及β-1,3-葡聚糖酶的活性,提高了蔗糖及β-1,3-葡聚糖含量,且施钾缓解作用随盐胁迫程度加重而逐渐减弱。施钾条件下,中棉所79的纤维素最大累积速率及β-1,3-葡聚糖酶活性的增幅高于泗棉3号。【结论】盐碱地适量施钾可缓解盐胁迫对棉花纤维断裂比强度的影响。

[Objective]The mechanism of sucrose metabolism of potassium regulating the cotton fiber strength under salt stress was investigated to provide theoretical basis for proper potassium application in saline-alkali land.[Methods]A field experiment was conducted to investigate the effects of potassium on the fiber strength,the accumulation of cellulose,the sucrose and callose content and related enzyme activities during the cotton fiber thickening of two cotton cultivars with contrasting salt sensitivity(CCRI 79,salt tolerant cultivar,and Simian 3,salt sensitive cultivar).Three potassium supply treatments(0,150,300 kg·hm^-2)under three soil salinity levels(Low salinity 1.68~1.78 dS·m^-1,Medium salinity 6.21~6.42 dS·m^-1,High salinity 10.59~11.08 dS·m^-1)were applied.[Results](1)Salt stress significantly reduced the strength of cotton fiber.The effect of medium and high salt on fiber strength was alleviated by potassium,but there was no significant difference between 150 and 300 K2 O kg·hm^-2.The effect of potassium on the fiber strength of CCRI 79 was better than that of Simian 3.(2)Salt stress reduced the accumulation of cellulose during the thickening stage,fiber sucrose content was reduced while the content of callose was increased.The maximum accumulation rate of cellulose,the activity of sucrose phosphate synthase andβ-1,3-glucanase at 28 days post anthesis were increased by potassium application,which increased the content of sucrose and callose.With the aggravation of salt stress,the alleviating effect of potassium gradually weakened.The maximum accumulation rate of cellulose and the increase ofβ-1,3-glucanase activity in CCRI 79 were higher than those in Simian 3.[Conclusion]The potassiumapplication under saline-alkali land can alleviative the effect on cotton fiber strength caused by salt.