香蕉种苗耗水规律及适宜节水灌溉制度研究

【目的】探讨香蕉育苗期的耗水规律,制定科学合理的节水灌溉制度。【方法】以‘巴西蕉’一级组培苗为材料,以椰糠为育苗基质,采用盆栽试验,设置6个水分上限(占田间持水率的百分比)处理:90%、80%、70%、60%、50%和40%(T90、T80、T70、T60、T50、T40处理),以100%相对含水率为对照(CK),每3天补水1次,测定了不同处理试验苗在苗期的日耗水量和生长生理指标。【结果】不同控水条件下的试验苗在整个苗期内单株日耗水量均呈上升趋势,各处理试验苗苗期总耗水量表现为:CK>T90处理>T80处理>T70处理=T60处理>T50处理>T40处理。在生长前期,T70处理的地上部指标的PCA得分最高,其叶片数和鲜质量分别较CK提高了16.67%和4.95%;在生长中期和后期,T80处理的得分最高,在生长中期,T80处理的茎粗和鲜质量分别较CK提高了15.64%和14.27%,在后期,茎粗和鲜质量分别较CK提高了34.62%和32.16%。根系的生长活跃度与基质相对含水率正相关,在生长前中期T80处理根系生长活力最强,而在生长后期T90处理根系生长活力最强。地上部与地下部异速生长模型为Y=0.1386·(x/r)0.7,R²=0.8076,模型评价的结果表明模型具有预测能力。【结论】香蕉苗期的最优节水灌溉制度为:在生长前期控制基质相对含水率为70%,中期和后期为80%。

Water Consumption of Banana Seedling and Suitable Water-saving Irrigation Scheme for It

【Background】Excessive irrigation and fertilization during seedling stage of banana are common in China,which is not only a waste of resources and increases costs,but also compromises plant quality and undermines healthy and sustainable banana production.【Objective】The purpose of this paper is to investigate water consumption of banana seedlings under different soil water contents,as well as its consequence for morphological and physiological traits in attempts to propose an improved water-saving irrigation scheme for banana production in China.【Method】We used the best tissue seedlings of the cultivar Mimosa nana Lour.as the model plant,and conducted the experiment in pots by controlling water content in them in the range from 20%to 90%of the field capacity,with keeping water content at the field capacity as the control(CK).During the experiment,we measured morphological and physiological traits of the plant for each treatment.【Result】Regardless of soil water contents,daily water consumption per plant increased first before plateauing as the plants grew.Increasing soil water content increased daily water consumption per plant,and the difference in water consumption between treatments was significant(P<0.05).Keeping soil water at 70%of the field capacity in the early stage was most effective in improving above-ground morphological and physiological traits,with the leaf numbers and fresh biomass weight increased by 16.67%and 4.95%,respectively,compared to CK.Keeping soil moisture at 80%of the field capacity increased stem diameter and fresh biomass weight at the middle and late stage by 15.64%and 14.27%,and 34.62%and 32.16%,respectively compared to CK;it also enhanced plant height at the late stage by 22.64%.The root traits depended on soil water content and the optimal soil moisture was 80%~90%of the field capacity.In early growth stage,keeping soil moisture at 80%of the field capacity boosted total root length and root surface areas by 19.98%and 19.79%respectively,while in the middle growth stage,it increased root surface area,average root diameter and volume by 12.38%,20.90%,and 32.06%,respectively,compared to CK.In late growth stage,keeping soil moisture at 90%of the field capacity increased root total length,root surface area and volume by 43.69%,42.78%,39.10%and 71.76%,respectively,compared to CK.The allometric model for above-and below-ground biomasses was Y=0.1386·(x/r)0.7,with R²=0.8076 and F>F0.01,P<0.01.【Conclusion】The optimal irrigation scheme for banana seedling was:keeping soil moisture at 70%of the field capacity during its early growth stage,and 80%of the field capacity at middle and late growth stage.The allometric model for above-and below-ground biomass can be used to predict change in root biomass based on the above-ground biomass.