水分胁迫下春小麦根系吸水功能效率的研究

The study of spring wheat root function efficiency under water stress conditions

对水分胁迫下不同根系大小的春小麦籽粒产量与水分利用效率、相对生长速度和根系功能效率之间的关系进行了研究.实验分为3个水分处理和3个根系大小处理,3个水分处理分别是土壤含水量保持在田间持水量的80%～90% H ,50%～60% M 和30%～40% L .根系大小的处理是 1 大根系处理 B , 2 中根系处理 M 和 3 小根系处理 S .实验结果表明,在中度和重度干旱条件下小根系处理 MS和LS 的作物具有较高的WEUg、WUEdm、相对生长速度、根系功能效率和籽粒产量;在高水分处理中,上述参数的数值在大根系处理中相对较高.根呼吸耗C量在作物的整个生育期中都占有十分重要的地位,尽管根呼吸耗C比例随作物的生长而呈同步增加的趋势,但实际耗C量却呈逐步下降的趋势,同一时期作物的根呼吸速率与土壤含水量之间存在正相关关系,说明适当降低土壤含水量可以有效地减少根呼吸耗C量,有利于提高作物的存活率.在干旱半干旱地区,春小麦的根功能效率尚未达到最高值,作物产量仍有潜力可挖,通过适时补灌和减少同化物向根系分配的比例和根系对同化产物的消耗量来达到提高春小麦籽粒产量的方法是可行的,但不是长久之计.

An experiment was conducted the relationship of grain yield on water use efficiency in producing grain (WUEg) and dry matter (WUEdm),relative growth rate (RGR),and root function efficiency (RFE).Spring wheat (Triticum aestivum) were subjected to three water regiems and three root treatment.The three water regiems were that the soil water content was controlled to 80%~90% (H),50%~60% (M) and 30%~40% (L) of the field water capacity,and the three root treatment were big root system (B),middle root system (M) and small root system (S).The experiment indicated that under the moderate and sever water stress conditions WUEg,WUEdm,RGR,RFE and grain yield were significantly higher in the small root treatments.While under fully irrigated conditions these parameters were relatively higher in big root system treatments.A large amount of carbon allocated to the ground was respired by root.Though the amount of carbon consumed by root respiration decreased with the development of plant,the proportion of carbon root respired was increased with the development of plant.The results suggested that we could decrease the carbon consumed by root respiration greatly by decreasing the soil water content,which may benefit to improve the survival of wheat under water stress conditions.In semiarid areas,the root function efficiency of spring wheat still wasnt attained its maximum value,and the way is available to increasing the grain yield by decreasing the proportion of dry matter allocated to the root system and the amount of dry matter consumed by the root system,but in the long run,it was unfavorable to the sustainable development of semiarid agriculture.Furthermore,irrigation at appropriate time is also an effective way to improve grain yield.