中文摘要：

河套灌区是全国受土壤盐渍化危害最为严重的地区之一。利用土柱试验和微区试验,研究了不同盐分条件下向日葵的根系分布,建立了基于根系总吸收面积和根长密度的两种根系分布函数（RAA函数和RLD函数）,并利用HYDRUS-1D软件对微区试验土壤含水率进行动态模拟,以评价分别应用RAA函数、RLD函数、Zuo函数和Ning函数这4种不同根系分布函数计算根系吸水速率的准确性。结果表明,应用RAA函数的土壤含水率模拟准确性在不同的盐分条件下均最优。尤其在受轻度盐分胁迫时,RAA函数较其他3种根系分布函数具有明显的优势。此外,还通过HYDRUS-1D软件计算得到向日葵逐日根系吸水量,表明在向日葵全生育期内盐分胁迫对根系吸水始终具有抑制作用,但是向日葵根系的耐盐性随生育期的推进而提升,盐分的抑制作用逐渐减弱。

英文摘要：

Hetao irrigation District is one of the areas which are troubled with serious soil salinization in China .This paper studied sunflower root distribution by pot experiments and built two different root distribution functions based on root absorption area （RAA） and root length density （RLD） .Meanwhile ,we simulated sunflower root water uptake during its whole growth period using different root distribution functions and HYDRUS-1D software .Compared with RLD function ,Zuo function and Ning function , RAA function always had the best performance in simulating soil water content ,especially in slight saline soils .Moreover ,daily root water uptake rate which was calculated by HYDRUS-1D showed that salt stress had an varying inhibiting effect on sunflower root water uptake at different growth stages .The inhibiting effect was alleviated with the enhancing salt tolerance of sunflower root after seedling growth .