旱农区春小麦根系生长冗余与碳平衡关系的研究

Study on the relationship between spring wheat root growth redundancy and carbon balance in semi-arid area

利用McCree 1986 测定整株植物碳平衡的方法,研究了半干旱区3个春小麦品种的籽实产量、根量、根冠比与碳平衡的关系.结果表明在开花期地方品种和尚头较之现代品种有更大的根量和根冠比.同一品种不同水分条件下根和茎叶CO2交换率 CER 波动幅度与水分条件正相关;在相同水分条件下不同品种间,品种和尚头波动幅度最大,品种定西-24次之,品种陇春-8139最小.从根和茎叶呼吸及日净碳获得量随水分供给条件的变化来看,品种和尚头和品种定西-24与品种陇春-8139相比在资源获取器官上存在着生长冗余,而且这种冗余也表现在生理代谢上,随水分条件的改善而增加.说明大根系品种在根系上存在着冗余,减少根系冗余可望成为半干旱区小麦高产育种的一条有效途径.

McCrees method (1986) was used to study the relationship of among spring wheat land race 'Heshangtou',modern variety 'Dingxi24' and modern variety 'Longchun8139' root growth redundancy and carbon balance in semiarid area of Loess Plateau in 1997 and 1998.It is shown that the modern variety Dingxi24 and 8139 is more productive than the landrace 'Heshangtou' when planted in monoculture,but when sowed in mixture Dingxi24 and 8139 will be eliminated in a few generations.There is a kind of negative correlation between competitive ability and productive performance in crop varieties.The reason is that the land race allocate more resources to the vegetive organs than the modern variety of spring wheat,thereby conferring a higher competitive ability on it.The relationships among seed yield,root size,root/shoot ratios and carbon balance of spring wheat varieties were studied in growth room.The results showed that the old landrace 'Heshangtou' has more root biomass,root/shoot ratios and higher root respiration than modern varieties 'Dingxi24' and 'Longchun8139' at florescence stage.There was significant difference in seed yield due to different soil water content and varieties (P>0.05).But there was not significant difference in seed yield due to different clipping root treatments (P>0.05).There were negative correlation between root weight and yield,root weight and aboveground biomass,root respiration and yield,root respiration and aboveground biomass.There maybe a root redundance,such as in landrace with a lower yield under the conditions of favourable rainfall.To reduce the root biomass to a suitable size may be a hopeful way for improving the yield of spring wheat varieties in semiarid area.