分根交替灌水对棉花生长、光合与水分利用效率的影响

Effects of Alternate Partial Root-zone Irrigation on Plant Growth,Photosynthesis and Water Use Efficiency in Cotton

应用部分根区干燥(PRD)技术,研究分根交替灌水(APRI)、分根固定灌水(FPRI)与全根系均匀灌水(BPRI)对盆栽棉花的生长、光合和水分利用效率的影响。结果表明:APRI黎明前与正午的叶水势均明显高于FPRI,而与BPRI无显著差异。APRI在叶片水分状况未变化时,显著降低了气孔导度,在维持光合作用不变的情况下,减少蒸腾量,瞬时水分利用效率与FPRI和BPRI相比分别提高了35.86%和63.51%。APRI处理的棉株在干旱复水后由于补偿效应,叶片生长速率和总叶面积较同等灌水量的FPRI分别提高了67.42%和27.16%。同时,干湿交替刺激APRI处理棉株的吸收根生长,其干重是FPRI的1.39倍。分根交替灌水在节水50%条件下,比同水量固定灌水处理的水分利用效率显著提高。

In this experiment, using partial root-zone drying technique （PRD） with pot-grown cotton plants, we compared the plant growth, photosynthesis and water use efficiency with water stress under alternative partial root-zone irrigation （APRI）, fixed partial root-zone irrigation （FPRI）, and both partial root-zone irrigation （BPRI）. It was found that the pre-dawn and midday leaf water potential in APRI and BPRI were approximately same, but higher than that in FPRI. Furthermore, the stomatal conductance in APRI decreased without obvious change in leaf water status, and transpiration rate declined significantly without much reduction in photosynthetic rate, therefore the photosynthesis water use efficiency improved by 35.86% and 63.51% respectively, as compared to that in FPRI and BPRI treatments. The results also revealed that the leaf growth rate and total leaf area in APR/increased by 67.42% and 27.16%, respectively, compared to that in FPRI at the same irrigation levels according to compensating effects. Further analysis revealed that cotton developed more feeder roots in APRI by using dry-wet alternative irrigation method, the dry mass of feeder roots improved 1.39 times compared to that of FPRI. With 50% reduction of water amount, APRI significantly improved the water use efficiency than FPRI.