刈割高度对冬小麦再生及生物量分配的影响

Regrowth and biomass allocation of dual-purpose winter wheat under two clipping heights

为确定刈割留茬高度对冬小麦(Triticum aestivum)光合产物累积及分配的影响,在温室盆栽条件下,对冬小麦陇育4号(LY)和运旱2号(YH)于分蘖期进行刈割处理,刈割留茬高度为6cm(R_6)和3cm(R_3),以不刈割为对照(CK)。结果表明,刈割留茬高度影响冬小麦株高增长,刈割后花期植株叶面积指数与CK无差异。在R_6和R_3处理下,LY的地上部生物量较CK分别下降了23%和3%,根生物量分别下降了12%和13%(P>0.05),YH的地上部生物量分别降低了22%和15%(P>0.05)、根系生物量分别下降了6%和0.1%(P>0.05)。刈割干扰使植株地上部生物量在全株中占比下降,茎干重在地上生物量占比下降,而叶干重占比上升。留茬6cm下,冬小麦花期地上、地下生物量分配格局与对照无差异,而留茬3cm下光合产物向地上部转移比例增加,意味着适度干扰可通过源库协调,释放生长冗余,维护籽粒形成。

A greenhouse experiment was conducted to reveal the response on regrowth and grain yield of winter wheat plants to clipping treatment. Two winter wheat （Triticum aestiwum） cultivars, Longyu 4 （LY） and Yunhan 2 （YH）, were used, and clipping was done at the tillering stage, with cutting treatments to 6 cm in height （R6）, to 3 cm in height （Ra）, and no-cut as control （CK）. The results showed that the leaf area index and net photosynthesis rate of the two cultivars at the anthesis stage after clipping recovered to control levels; the aboveground biomass and root biomass of LY under R6 and R3 decreased by 23% and 3% （P〉0.05）, and 12% and 13% （P〉0.05） in comparison with CK, respectively. The ahoveground biomass of YH decreased bY 22% and 15% （P〉0.05） compared with its control under R6 and R3, however, root biomass under Ra was equal to its control. Clipping caused the proportion of aboveground biomass in the whole plant to decline, and ratios of stem to leaf in aboveground parts decreased and increased, respectively. There was no difference in biomass allocation patterns aboveground or below ground between R6 and CK; However, a higher proportion of dry matter transferred to aboveground under R3 than that under CK, implying that suitable cutting disturbance may release growth redundancy through the source-sink coordination to maintain grain yield formation.