干旱胁迫下栽植模式对葡萄根际土壤湿度和光合效率的影响

Effect of Different Cultivation Planting Patterns on Rhizosphere Soil Moisture and Photosynthetic Efficiency under Drought Stress in Grapes

为了解西北干旱地区深畦栽植模式对葡萄光合效率的影响,试验以鲜食葡萄品种‘京亚’和‘红地球’为材料,以葡萄生产中常用的平畦栽植模式为对照,研究了深畦栽植模式对葡萄根际土壤湿度及光合效率的影响。结果显示:(1)干旱胁迫过程中,2种栽植模式的葡萄根际土壤相对含水量、气孔导度(Gs)、净光合速率(Pn)、蒸腾速率(Tr)、水分利用效率(WUE)均持续下降,但深畦栽植的土壤相对含水量和WUE较平畦栽植下降缓慢,且在胁迫后期严重干旱时两者均明显高于平畦栽植。(2)根据Logistic模型对土壤相对含水量与Pn、Gs、Ci、Tr的关系的曲线拟合结果,发现深畦栽植和平畦栽植下土壤相对含水量区间分别为30%~50%和40%~60%时显著影响葡萄的光合水分效率。(3)以Logistic方程的拐点为根际土壤湿度阀值,发现深畦栽植和平畦栽植葡萄的根际土壤湿度阀值分别为41.76%和52.60%,且此时葡萄光合水分效率最高。研究表明,在干旱逆境下,与平畦栽植相比,深畦栽植下能够有效减缓根际土壤水分散失,保持较高的根际土壤含水量,而且能够在土壤含水量较低的条件下实现更高的光合水分效率,深畦栽植是干旱地区理想的葡萄抗旱节水栽植模式;深畦栽植下,葡萄品种‘京亚’和‘红地球’的根际土壤相对含水量分别在40.19%和43.32%时叶片光合水分效率最高,且两葡萄品种光合作用的适宜土壤相对含水量范围分别是40.19%~50%和43.32%~50%。

The study aimed to explore the effect of deep-furrow planting pattern on photosynthetic efficiency of grape in the northwest arid region.The effects of deep-furrow planting pattern on the rhizosphere soil moisture and photosynthetic efficiency were studied with flat-furrow planting pattern as control using the table grape types of‘Jingya＇and ‘Red globe＇as testing materials.The results showed：（1）under drought stress,the rhizosphere soil relative water content,net photosynthetic rate（Pn）,stomatal conductance（Gs）,Intercellular CO2 concentratio（Ci）,Transpiration rate（Tr）and water utilization efficiency（WUE）of grapevine in both deep-furrow planting and flat-furrow planting continued to drop;However,the rhizosphere soil relative water content and WUE under deep-furrow planting dropped at a slower rate than those under flat-furrow planting.In addition,during severe drought（towards the later part ofdrought stress）,the rhizosphere soil relative water content and WUE under deep-furrow planting were significantly higher than those under flat-furrow planting.（2）Based on a logistic model,curve fitting was performed for the correlation between the soil relative water content to Pn,Cond,Ci,and Tr,and the following was revealed：relative water contents of 30%-50% and 40%-60% were the two ranges that significantly affected the photosynthetic efficiency in grapevines under deep-furrow planting and flat-furrow planting,respectively.（3）The inflection point of the logistic equation was defined as the soil moisture threshold.The rhizosphere soil moisture threshold was the point of highest efficiency in water utilization and photosynthesis for grapevine.Test results showed that the threshold of rhizosphere soil moisture in deep-furrow planting and flat-furrow planting were 41.76% and 52.60%,respectively.The above results apparently showed that under drought stress when compared with flat-furrow planting,water loss in rhizosphere soil could be effectively reduced in grapevines planted in deep furrow so that the WUE was higher in photosynthesis taking place in grapevines and higher photosynthesis efficiency could be achieved even when soil moisture was lower.Thus,deep-furrow planting is an ideal drought-resistant planting pattern for cultivating grapes in arid areas.In deep-furrow planting,the test results suggested that the rhizosphere soil relative water content of 43.43% and 40.19% were the most effective soil moisture that generated the highest WUE during photosynthesis in the leaves of‘Jingya＇and‘Red Globe＇,respectively;the appropriate soil moisture range for‘Jingya＇and‘Red Globe＇were 43.32%-50%and 40.19%-50%,respectively.