光周期对燕麦生育时期和穗分化的影响

盆栽试验研究了不同光周期对不同熟期燕麦品种的穗分化进程和生育时期影响及生理生态机制。试验材料包括早熟品种白燕8号,中熟品种白燕2号以及晚熟品种坝莜3号,跟踪测定了叶片保护酶活性、膜脂过氧化作用和质膜透性等生理指标的动态变化。结果表明,晚熟品种坝莜3号对光周期反应敏感,短日照(8h)条件下,其穗分化只能到二棱期,未能正常抽穗;早熟品种白燕8号在短日照条件下可完成穗分化、抽穗开花,但3个品种生育时期和穗分化时间均延长。随着光周期延长,各燕麦品种单株小穗数和穗重均增加。光周期对穗分化进程的影响机制可从叶片保护酶活性、膜脂过氧化作用和质膜透性等指标中得到证明,白燕8号在8h短日照处理下SOD,POD活性均高于白燕2号和坝莜3号,而MDA含量和相对电导率低于另两个品种。MDA含量和相对电导率与光周期呈显著正相关。燕麦早熟性与光周期不敏感性具有一定相关性,且燕麦光周期适应性调控机理可能与保护酶活性、膜脂过氧化作用和质膜透性等生理变化密切相关。

Ecophysiological mechanism of photoperiod affecting phenological period and spike differentiation in oat (Avena nuda L.)

A controlled pot culture experiment was conducted to determine the influence of different photoperiods on the phenological progression, spike differentiation and development of oat varieties differing in maturity. Three varieties (Bayou3, representing a late maturity variety, Baiyan8 representing an early maturing variety and Baiyan2 representing an intermediate maturating variety) were treated with 8, 12, and 16 h photoperiods, in a factorial arrangement with three replications. Phenological traits and apical development were monitored at weekly intervals. At the jointing, booting, heading and grain-filling stages, superoxide dismutase (SOD), peroxidase (POD), malondialdehyde (MDA) and relative cell membrane conductivity (REC) were determined after destructive leaf sampling. Our results showed that the late maturing Bayou3 was sensitive to photoperiod and was unable to complete spike differentiation and reach heading under 8 h photoperiod. Variety Baiyan8, on the other hand was not sensitive to changes in photoperiod. All varieties took longer to reach specific phenological stages and spike differentiation with the 8 h photoperiod. The SOD and POD activities were greater for Baiyan8 than for Bayou3 and Baiyan2. In contrast, Baiyan8 had lower MDA content and lower REC than the other two varieties. MDA content and REC were correlated with photoperiod. Our data indicate that the earliness per se of oat was related with photoperiod insensitivity, and there was also a relationship between foliar antioxidant enzyme activity and the response of varieties to photoperiod.