Abstract: 【Objective】 The objective of this experiment is to study the effect of alternative partial root-zone irrigation on the physiological and ecological characters of cotton. 【Method】With pot-grown cotton plants, the current study compared the physiological effects, growth and allocation of photosynthetic produces under alternative partial root-zone irrigation (APRI), fixed partial root-zone irrigation (FPRI), and conventional full root-zone irrigation (CK). 【Result】 It was found that with 50% reduction in the amount of irrigation as compared with CK, biomass in APRI reduced by only 10%, while in FPRI the reduction was 23%. The results also revealed that although the total amounts of root biomass were the same in every treatment, the root/shoot ratio in APRI and FPRI increased significantly. Further analysis revealed that, the total amount of absorbing roots in CK and APRI were approximately the same, but higher than in FPRI in both cases. With partial root-zone irrigation, ABA content in leaves and stems increased significantly, which regulated the water loss through adjusting stomatal opening.【Conclusion】Results show that APRI could stimulate the growth of absorbing roots, adjust allocation of photosynthetic produces between shoots and roots, therefore it is a promising irrigation method for saving water and keeping reasonable crop product.

Key words: cotton, partial root-zone drying, alternative partial root-zone irrigation, abscisic acid, biomass