根土空间对藜麦根系冗余及生理特性的影响

Effects of soil root-growing space on root redundancy and physiological characteristics of quinoa

采用等体积不同根土空间构型的根管土柱栽培方法(直径为10 cm、高60 cm的根土空间V1和直径15.2 cm、高26 cm的根土空间V2),旨在揭示根系生长空间和种植密度(D1:1株/管;D2:2株/管;D3:3株/管;D4:4株/管;D5:5株/管)在藜麦生长过程中是否存在根系冗余现象以及对其生理特性的影响.结果显示,相同种植密度条件下,根土空间V1在灌浆期的株高、茎粗、叶面积、根长、根体积、根表面积、地上干物质量、根系干物质量、相对叶绿素含量、SOD酶活、POD酶活和根系活力等分别比根土空间V2平均增加4.78%、10.41%、20.65%、29.04%、7.02%、7.78%、37.40%、48.42%、35.02%、15.80%、56.74%和6.90%,而根冠比和活性吸收面积(%)的趋势与上述指标相反,分别平均下降了9.10%和5.47%;当根土空间(体积、构型)相同时,藜麦的以上指标均随着种植密度的增加呈下降趋势,且表现为D3处理之后,密度增加越大,其各个指标下降幅度就越大;产量则随着种植密度的递增呈先增加后降低的相似变化动态,表现为根土空间V1在种植密度为3株时产量最高,根土空间V2在种植密度为4株时达到极值,但是V1D3的产量比V2D4平均增加了33.00%.本研究表明,“窄而深”的根土空间V1能促使植株根系向下层深扎,以获取底层的养分;适当的根土空间和合理的种植密度(V1D3)可以促进藜麦更好的生长,有效减少根系冗余.(图3表3参42)

The aim of this study was to investigate whether root redundancy exists during quinoa growth under different planting densities and root spaces,and its effect on the physiological characteristics of quinoa.We conducted a column experiment with different planting densities(D1,1 plant per column;D2,2 plants per column;D3,3 plants per column;D4,4 plants per column;and D5,5 plants per column)in custom-built soil columns of the same volume and different shapes(V1,cylindrical with a diameter of 10 cm and a height of 60 cm;V2,cylindrical with a diameter of 15.2 cm and a height of 26 cm).The results showed that under the same planting density,the plant height,stem diameter,leaf area,root length,root volume,root surface area,aboveground dry matter mass,root dry matter mass,relative chlorophyll content,superoxide dismutase(SOD)enzyme activity,peroxidase(POD)enzyme activity and root activity of V1 in the filling period were 4.78%,10.41%,20.65%,29.04%,7.02%,7.78%,37.40%,48.42%,35.02%,15.80%,56.74%and 6.9%higher than those of V2,respectively.Meanwhile,the root shoot ratio and active absorption area(%)of V1 in the filling period were 9.10%and 5.47%lower than those of V2,respectively.The above indicators of quinoa all showed a decreasing trend with increasing planting density under the same root space conditions(volume and shape),the greater the density increases,the greater the decline of each indicator under D3,D4,and D5 treatments.The yield first increased and then decreased as planting density increased,with the highest yield at planting densities of three per column for V1 and of four per column for V2.Moreover,the average yield of V1D3 was 33.00%higher than that of V2D4.In conclusion,the“narrow and deep”root space of V1 encouraged plant roots to dig deeper to obtain nutrients from the bottom layer.Proper root space and reasonable planting density(V1D3)can promote better quinoa growth and effectively reduce root redundancy.