摘要
通过盆栽控光试验,研究不同生育阶段遮荫对冈优906根系生长的影响以及不同品种对弱光胁迫的响应.结果表明:抽穗前遮荫处理,随遮荫程度加重,冈优906根系体积、总吸收面积和活跃吸收面积均有所降低,根系生长受到抑制;始穗后轻度遮荫处理(遮53%光强),其根系体积、总吸收面积、活跃吸收面积和根冠比增加,根系生长得以促进,衰老延迟;始穗后重度遮荫(遮73%光强)则不利于其根系正常生长,根系体积、总吸收面积、活跃吸收面积和根系α-萘胺氧化力降低.不同品种根系生长对弱光的反应不同:冈优906耐荫性较强,有较高的根系α-萘胺氧化力和活跃吸收面积;耐荫性较弱的Ⅱ优498则表现为根系α-萘胺氧化力和活跃吸收面积的较大幅度减少.灰色关联度分析表明,根系α-萘胺氧化力和活跃吸收面积可以作为耐荫性敏感鉴定的有效指标.
Rice （Oryza sativa L.） as a photophilous crop, often encounters low-light environment during the growth stage in rice-producing areas particularly in Sichuan. Low-light stress seriously affects the morphology, physiology, grain yield and quality of rice. However, the response of rice root system to low-light stress is not so far clear. Therefore, we seeks to examine the responses of five rice varieties to low-light stress at different growth stages through pot experiments under artificially-controlled shading condition using white cotton yarn screen. By a completely randomized design, the pot experiments were carried out on the experimental farm of Sichuan Agricultural University in 2009. In experiment 1, one-layer and two-layer white cotton yarn screens, which shaded about 53 % and 73 % of the full light intensity respectively, were covered on the top of rice canopy of Gangyou 906 at tillering-elongation stage, elongation-booting stage, booting-heading stage, and heading-maturing stage respectively. In experiment 2, the response of root system of Ⅱ you 498, Gangyou 188, Gangyou 527 and Chuanxiang 9838 to shading was studied at tillering-elongation stage and booting-heading stage by covering with one-layer white cotton yarn screen. The screens were more than 2.0 m above the ground to ensure good ventilation and were large enough to fully cover the shaded plots. Plants without covers were set as control （CK）. Root/shoot ratio, root volume, maximal root length, root total absorbing area, root active absorbing area and root α-naphthylamine oxidizing activity were analyzed at the end of shading treatment. The results were as follows： 1） Root volume, root total absorbing area and root active absorbing area of Gangyou 906 were decreased with the increase of shading degree before filling stage, resulting in root growth retard （Fig. 1, 2）. At tillering-elongation stage and elongation-booting stage, shading greatly （P 〈 0.05） reduced root volume, and the decline was severe with the increase of low-light stress. As compared with the control, root volume was significantly decreased （P 〈 0.05）, but the decrement with treatment of 53 % shading was greater than that of 73 % shading at booting-heading stage. Root total absorbing area and active absorbing area significantly （P 〈 0.05） decreased with the increase of shading intensity at elongation-booting stage and booting-heading stage. After heading stage, the root system growth was promoted, while the root senescence was delayed under 53 % shading treatment. Meanwhile, the root volume, root total absorbing area and active absorbing area increased by 14.6 %, 17.5 % and 39.5 % respectively with 53 % shading treatment. However, 73 % shading treatment had negative effects on root volume, root total absorbing area, root active absorbing area and α-naphthylamine oxidizing activity in roots （Fig. 1-3）. 2） The responses of different varieties to shading treatment were different. Shading significantly （P 〈 0.05） reduced root α-naphthylamine oxidizing activity, root absorbing area and active absorbing area of Ⅱyou 498, Gangyou 188 and Gangyou 527 （Table 3, 4）, leading to the hindrance of the formation and capacity of moisture and mineral nutrients of root system. But for Gangyou 906, the root α-naphthylamine oxidizing activity with 53% and 73% shading treatment at tillering-elongation stage and booting-heading stage were 104.7 %, 35.5 %, 83.2 %, and 0.5 % respectively higher than those of non-shading treatment. It can be concluded that different degrees of shading have different influences on root system characteristics of rice at each growth stage, and strong shade-tolerant variety such as Gangyou 906, can reduce the disadvantaged effect on grain yield of rice by improving the vigor of root system. It also suggests that the root α-naphthylamine oxidizing activity and root active absorbing area can be used as effective indicators to identify the low-light tolerance of rice with the grey correlation degree analysis （Table 5）. All these results lay a theoretical foundation for the selection of shade-tolerant variety and the improvement of cultivation technology.
出处
《浙江大学学报（农业与生命科学版）》
CAS
CSCD
北大核心
2012年第6期700-708,共9页
Journal of Zhejiang University:Agriculture and Life Sciences
基金
国家粮食丰产科技工程资助项目(2006BAD02A05
2012BAD04B13-2)
四川省育种攻关课题资助项目
关键词
水稻
弱光胁迫
生育阶段
品种
根系生长
flee
low-light stress
growth stages
varieties
root system growth
