慈姑(Sagittaria trifolia)根系泌氧特征  

Oxygen Excretion by Roots of Sagittaria trifolia

作　　者：夏劲[1] 王国祥[2] 王文林[2,3] 刘波[2] 

机构地区：[1]南京师范大学生命科学学院,江苏南京210046 [2]南京师范大学地理科学学院/江苏省环境演变与生态建设重点实验室,江苏南京210046 [3]环境保护部南京环境科学研究所,江苏南京210042

出　　处：《生态与农村环境学报》2012年第4期422-426,共5页Journal of Ecology and Rural Environment

基　　金：国家自然科学基金(40873057;41173078)

摘　　要：借助高精度溶解氧微电极,研究了自然沉积物中慈姑(Sagittaria trifolia)根不同部位的泌氧能力差异以及光照对根系泌氧能力的影响。结果表明,慈姑根系不同部位的泌氧能力存在差异,光照和黑暗条件下根区氧气扩散层厚度由大到小依次为1/2根长(0.98、0.72 mm)、3/4根长(0.68、0.28 mm)、根尖(0.58、0.44 mm)和1/4根长(0.42、0.32 mm);光照条件下不同根长部位根表面溶解氧含量由大到小依次为1/2根长〔64.56%(以%空气饱和度计)〕、3/4根长(52.73%)、根尖(38.55%)和1/4根长(20.55%),这与根部泌氧屏障、通气组织发育程度和根组织呼吸代谢有关。无论有无光照,慈姑根均有泌氧产生,光照条件下根表面溶解氧含量和根区氧气扩散层厚度均高于黑暗条件;在光照和黑暗条件下1/2根长处根表面溶解氧含量均显著高于其他测定点(P<0.05);除1/2根长处以外的其他测定点,在光照条件下的根表面溶解氧含量差异显著(P<0.05),但在黑暗条件下趋于相同(P>0.05)。Root excretion of oxygen is an important feature of Sagittaria trifolia.For better understanding the characteristics of the radial oxygen loss（ROL） from roots of the plant in natural sediment,high-precision dissolved oxygen microelectrodes were used to measure penetration depth and distribution of oxygen under different light intensities（dark and light）.Substantial difference in oxygen distribution was observed between parts of the roots.Thickness of the oxygen diffusion layer in the rhizosphere under light and in dark varied along the root in the following order：at 1/2 of the root length（0.98 and 0.72 mm）〉at 3/4（0.68 and 0.28 mm）〉at root tip（0.58 and 0.44 mm）〉at 1/4 of the root（0.42 and 0.32 mm）.Content of dissolved oxygen on root surface under light varied along the root in the following order：at 1/2 of the root length（64.56% of air saturation）〉at 3/4（52.73%）〉at root tip（38.55%）〉at 1/4（20.55%）,which was related to barrier to ROL,development of aerenchyma,and metabolism and respiration of the tissue.ROL from the roots of S.trifolia,no matter under light or in dark,occurs all the time,and is significantly affected by light intensity.Both the content of dissolved oxygen on root surface and the thickness of the oxygen diffusion layer in the rhizosphere are higher under light than in dark.Among all the measuring points,the point at 1/2 of the root length had the highest ROL in both light conditions（P0.05）.

关 键 词：泌氧 微探头 慈姑 根区 

分 类 号：Q178[生物学—水生生物学] Q945[生物学—普通生物学]