干旱胁迫下不同基因型小麦干物质转运对产量形成的影响

Effects of dry matter translocation on yield formation of wheat with different genotypes under drought stress

为了探讨干旱胁迫下不同基因型小麦干物质转运特性及其对产量形成的影响,以二倍体野生一粒小麦(T.boeoticum)、栽培一粒小麦(T.monococcum)、四倍体野生二粒小麦(T.dicoccoides)、栽培二粒小麦(T.dicoccon)和2个六倍体小麦品种为材料。在充分供水(田间持水量的75%~80%)和干旱(田间持水量的50%~55%)两种水分处理下,测定分析了不同基因型小麦花前干物质转运、花后干物质积累、运输能力、抗氧化防御能力及籽粒产量和产量构成等性状的变化,探究不同基因型小麦干物质转运对小麦产量形成的影响及其调控机理。结果表明,干旱胁迫显著降低了小麦籽粒产量。相比于充分供水条件,在干旱胁迫下,二倍体小麦野生一粒、栽培一粒,四倍体小麦野生二粒、栽培二粒,六倍体小麦小偃22、长旱58籽粒产量分别为降低了48.00%、37.93%、40.19%、38.77%、19.58%、16.11%,相比于二倍体和四倍体小麦,六倍体小麦籽粒产量具有较高稳定性,且六倍体小麦籽粒产量显著高于二倍体和四倍体小麦。干旱胁迫显著降低了不同基因型小麦干物质转运量和积累量,相比于充分供水条件,二倍体小麦野生一粒、栽培一粒,四倍体小麦野生二粒、栽培二粒,六倍体小麦小偃22、长旱58花前干物质转运量分别降低了29%、27%、30%、14%、3%、8%,花后干物质积累量分别降低59%、42%、44%、45%、23%、17%。干旱胁迫对不同基因型小麦干物质转运率和贡献率的影响存在差异,与充分供水条件相比,二倍体小麦野生一粒、栽培一粒,四倍体小麦野生二粒、栽培二粒,六倍体小麦小偃22、长旱58花前干物质转运率分别降低了40%、38%、36%、6%、-16%、-17%,贡献率分别降低了43%、37%、15%、26%、20%、11%,花后干物质贡献率分别提高了5%、-3%、13%、6%、2%、2%。同时发现,干旱胁迫下不同基因型小麦相比,六倍体小麦叶绿素含量、干物质运输能力和抗氧化防御能力均显著高于二倍体和四倍体小麦。以上结果说明,干物质转运和积累是小麦产量形成的关键因素。小麦花后持绿时间、抗氧化防御能力和运输能力影响小麦花后干物质的积累和转运,进而影响小麦籽粒产量的形成。

Six wheat genotypes including two diploid wheat,two tetraploid wheat and two hexaploid genotypes were used to evaluate the effect of dry matter translocation on grain yield formation and its regulation mechanism.The results indicated that drought stress significantly reduced grain yield of wheat.Compared with sufficient water supply,the grain yields of Triticum boeoticum,T.monococcum,T.dicoccoides,T.dicoccon,Xiaoyan 22,Changhan 58 were reduced by 48.00%,37.93%,40.19%,38.77%,19.58%and 16.11%,respectively,under drought condition.Compared with diploid and tetraploid wheat,the grain yield of hexaploid wheat was more stable.The grain yield of hexaploid wheat was significantly higher than that of diploid and tetraploid wheat.Drought stress significantly reduced the dry matter translocation amount and accumulation,compared with sufficient water supply conditions.Dry matter translocation amount before anthesis was decreased by 29%,27%,30%,14%,3%and 8%in Triticum boeoticum,T.monococcum,T.dicoccoides,T.dicoccon,Xiaoyan 22,and Changhan 58.The accumulation after anthesis was decreased by 59%,42%,44%,45%,23%and 17%in Triticum boeoticum,T.monococcum,T.dicoccoides,respectively.However,drought stress had different effects on the dry matter translocation rate and contribution rate in wheat with different genotypes.Compared with sufficient water supply conditions,the dry matter translocation rate of Triticum boeoticum,T.monococcum,T.dicoccoides,T.dicoccon,Xiaoyan 6,and Changhan 58 was reduced by 40%,38%,36%,6%,-16%and-17%before anthesis.The contribution rate was decreased by 43%,37%,15%,26%,20%and 11%,respectively,and the dry matter contribution rate was increased by 5%,-3%,13%,6%,2%and 2%after anthesis.Interestingly,the chlorophyll content,dry matter translocation capacity and antioxidant defense capacity in the hexaploid wheat were higher than those in the other wheat with different genotypes under drought stress.These results indicated that dry matter translocation and accumulation were key factors in grain yield formation.Higher dry matter translocation and accumulation under drought stress environment were associated with higher chlorophyll content,antioxidant defense ability and larger vascular bundle transport capacity to affect wheat yield.