不同基因型春小麦根系吸水功能效益的比较研究

This research compared root energy consumption and the influencing factors in various spring wheat cultivars developed in decades in dryland farming system of Gansu province to explore grain yield potential through regulation of assimilates partitioning between shoots and roots in future breeding. A pot experiment with 10 spring wheat cultivars developed in recent 50 years showed that total of root biomass C and root respiration C in these cultivars are as follows: earlier cultivars > metaphase cultivars > modern cultivars. Photosynthesis rate in the earlier cultivars reaches high level during the early period growth, but decrease markedly in medium and late growth periods. However, the metaphase and modern cultivars have low photosynthesis rate and low root biomass before anthesis, but increase prompt photosynthesis rate after anthesis, and keeping the higher level than the earlier cultivars until maturation of plants. This is favorable to increasing grain yield and harvest index. Earlier cultivars can still maintain relative high grain yield under drought stress conditions, while modern cultivars are relative sensitive to drought but have a relative higher grain yield potential in relative wet environment. In the experiment of drought tolerance with three typical cultivars representing the earlier, metaphase and modern times, plants die earlier in old cultivars than in modern cultivars; when three cultivars grow in one pot the three cultivars plants die still as the same time sequence of above mentioned, but delay 2-3 days in all the cultivars. This show that old cultivars transpire faster than the modern one, exhausted soil water earlier than the modern cultivars, which result in the low root efficiency, water use efficiency and grain yield, but modern cultivars have relative high root efficiency, water use efficiency and grain yield. A significantly correlation was found between ABA content of leaves and root biomass in various spring wheat cultivars, plants with high root biomass can accumulate more ABA in leaves and lead to die earlier than that of low root biomass in drought environment. This may be a cost of increase competitive ability through enlarging root system of plants in natural environment. In crop population, relative low root biomass decrease ABA accumulation in leaves, which is favorable to maintain relative high physiological activity, and further to get high shoot biomass and grain yield. A suitable combination of rooting depth and deep soil moisture regime can increase root efficiency, water use efficiency and grain yield. Grain yield and root efficiency in modern cultivars would decrease when mixed cultivation with old ones because of the weak soil water competitive ability in the formers. Therefore, the difference of grain yield and root efficiency between modern and old cultivars become smaller when mixed cultivation.

把根对地上供应水分、改善生产能力的水平同消耗同化产物之间的对比关系作为根系水的功能效益。不同年代春小麦品种与近源野生一年生小麦植物作为研究材料，测定根系分泌物、根呼吸和根生物量作为对光合产物的消耗，测定根对水的吸收、干物质生产集籽粒产量作为收益，分析比较根的产投效率，探讨通过影响根系对同化产物的消耗，提高产量的可行性。