利用根管法对油菜和冬小麦苗期根系形态的研究

快速、准确的根系原位观测方法是根系研究中的重要技术,本研究介绍了一种根管盆栽方法,该方法在透明PVC管内种植作物,通过遮光膜保持管内黑暗环境,以实现在作物生长过程中对其根系生长的原位动态观测,且根系生长环境更接近田间实际情况,并可通过改变根管长度、半径等将其应用于田间深根作物的研究中。利用此方法、结合根系扫描技术分析了油菜和冬小麦从发芽到出苗后16 d时的根系生长情况。结果表明,出苗后7和16 d冬小麦根系和地上部干物重均大于油菜,出苗后16 d冬小麦和油菜根冠比分别为0.513和0.372。大部分根系分布在0~16 cm表层土壤中,出苗后16 d冬小麦和油菜表层土壤中的根长在总根长中的比例分别为62.60%和67.76%,根系总表面积、总体积和一级侧根数均为表层土壤中占比最多,在出苗后7 d,总根长、总表面积、总体积和一级侧根数均为冬小麦显著高于油菜,而在出苗后16 d,两种作物的总根长和总表面积差别不大,说明油菜根系生长呈先缓后快趋势。表层土壤中根系平均直径小于底层土壤,油菜根系平均直径小于冬小麦,油菜和冬小麦的根系直径均大部分在0~0.50 mm之间,随着根系生长,较细的侧根逐渐增多,根系平均直径变小。出苗后16 d内的冬小麦根系伸长速率为1.83 cm/d,大于油菜的1.51 cm/d。因此,冬小麦苗期根系生长快于油菜,油菜根系呈先缓后快的生长特性。本研究介绍的根管法是一种原位研究根系的有效方法。

Comparison of the root morphology of oilseed rape and winter wheat during the seedling period using a rhizotron tube method

Fast and accurate methods for determining root growth in situ are important tools.In the present study,a rhizotron tube method was trialed as a means to more conveniently observe the dynamic development of roots under conditions similar to those encountered in the field.Crops were planted in transparent tubes covered with photomask to ensure a dark environment in the tube.This method can also be used in field studies of deep root development in crops by changing the length and diameter of the tube.Combined with root scan technology,we investigated the dynamics of root growth in oilseed rape and winter wheat at the seedling period from 16 days after germination.The results showed that winter wheat had a larger root and shoot dry weight than oilseed rape at both 7 days and 16 days.For winter wheat and oilseed rape,the root to shoot ratios at 16 days after germination were 0.513 and 0.372 respectively;the ratios of root length to total root length in the top soil layer (0-16 cm) were 62.60％ and 67.76％ respectively.The total surface,total volume and number of first class lateral roots of the two crops both had larger percentages in the top soil layer,indicating that most of the roots were distributed in the top 16 cm soil layer at 16 days.At 7 days after germination,the total length,total surface,total volume and number of first class lateral roots in winter wheat were higher than those in oilseed rape,while there were no differences between the two crops for the total length and total surface of roots at 16 days,suggesting that the root growth of oilseed rape was slow in the beginning but fast thereafter.The average root diameter in top soil was smaller than that in the deep soil layer,and the average root diameter of oilseed rape was smaller than that of winter wheat,which was typically between 0-0.50 mm.In terms of root growth,there were more and more thinner lateral roots,meaning that average root diameter became smaller.At 16 days after germination,the root elongation rate of winter wheat was 1.83 cm/d,larger than that of oilseed rape (1.51 cm/d).In conclusion,the root growth of winter wheat at the seeding stage was faster than that of oilseed rape,and the root of oilseed rape grew slowly at the beginning but faster thereafter.The rhizotron tube method introduced in this research is recommended as an effective method for root study in situ.