拔节期干旱胁迫对青贮玉米生育与品质的影响

为明确拔节期干旱胁迫对青贮玉米生育性状和品质的影响，以粮饲兼用型品种‘中原单32’为试验材料，在遮雨棚内进行控水试验，对比分析拔节期中度与重度胁迫条件下青贮玉米的生育期、植株形态、单株干物质量及品质指标的变化趋势。结果表明：青贮玉米在拔节期遭遇干旱胁迫后，生育进程推迟，拔节至吐丝间隔时间延长2～6 d，吐丝至成熟的间隔时间缩短1～4 d；株高与叶面积生长受阻，单株干物质量、干鲜比与果穗率降低；粗蛋白、酸性洗涤纤维、中性洗涤纤维含量上升，干物质、淀粉含量下降，综合评定指标相对饲喂价值和粗饲料分级指数下降。且干旱胁迫越严重、干旱胁迫时间越长，对上述指标影响越大。复水后，株高、叶面积均表现出明显的补偿效应，但与正常供水相比(T1)不能实现等量补偿。表明拔节期干旱胁迫导致青贮玉米生长速度减缓，单株干物质量下降，品质下降。

Influence of Drought Stress on Growth and Quality of Silage Corn at Jointing Stage

In order to clarify the effect of moderate and severe drought stress at jointing stage on growth character and quality of silage corn, using a grain and feed variety ‘Zhongyuandan 32’ as the experimental material, this paper performed water controlled experiments in rain shed to analyze the change trend of growth period, plant morphology, dry matter mass per plant and quality indexes of silage corn. The results showed that drought stress at the jointing stage delayed growth process of silage corn, extended the interval from jointing to silking by 2～6 d, and shortened the interval from silking to ripening by 1～4 d. Plant height and leaf area were inhibited, dry matter mass per plant, dry to fresh ratio and ear rate decreased. The content of crude protein, acid detergent fiber and neutral detergent fiber increased, the content of dry matter and starch decreased, the comprehensive evaluation indexes relative forage value and grading index decreased. The more severe drought stress was, the longer the drought stress was, the greater the impact on the above indexes of silage maize was. After rehydration, plant height and leaf area showed obvious compensation effect, but compared with normal water supply (T1), equivalent compensation could not be achieved. So drought stress at jointing stage results in slow growth decreased dry matter mass per plant and quality of silage corn.