滴灌水钾一体化对猕猴桃光合特性的影响

The effect of water-potassium integration in drip irrigation on the photosynthetic characteristics of kiwifruit

为探明不同滴灌水钾一体化管理对猕猴桃光合特性的影响,以8 a生金艳猕猴桃为试材,设置对照处理CK(在果实膨大期即III期、果实成熟期即IV期灌水量分别为31.2、26.4 m^3·667m^-2,施钾量分别为6.0、7.8 kg·667m^-2),在III、IV期分别设置3个亏水水平(即轻度、中度、重度水分亏缺,记为LD、MD、SD,灌水量分别为CK的80%、60%、40%)和2个施钾水平(即低钾、高钾,记为LK、HK,施钾量分别为CK的60%和80%)。结果表明:果实膨大期、果实成熟期不同滴灌水钾一体化处理的光合指标日变化趋势相似;LD处理下叶片净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、瞬时水分利用效率(WUEi)、羧化速率(CE)均随施钾量增加而增大,果实膨大期LDHK处理的Pn、CE较LDLK处理分别高15.71%、16.80%,果实成熟期LDHK处理的Pn、Gs较LDLK处理分别高6.07%、12.76%,差异达显著水平(P<0.05);SD处理下,除胞间CO2浓度(Ci)外各光合指标均较CK显著下降(P<0.05);MD处理下,除Ci、WUEi外各光合指标均较CK显著下降(P<0.05);施钾量一定时,除Ci、WUEi外各指标均随灌水量增加而显著增大(P<0.05),增幅为11.42%~64.40%;与CK处理相比,果实膨大期LDHK处理Pn提高11.38%(P<0.05),WUEi提高3.06%,CE提高10.83%;IV-LDHK处理Pn提高0.96%,WUEi提高2.00%。综合比较采用果实膨大期LDHK处理及果实成熟期LDHK处理,可在相应生育期节水节肥20%,日光合能力较强,是猕猴桃较适宜的滴灌水钾一体化管理模式。

In order to find out the effect of different water-potassium(K)integrated management on kiwifruit photosynthesis,the Jinyan kiwifruit for 8 years was selected as the test material.There was a control treatment with irrigation amount of 31.2 m^3·667m^-2 and 26.4 m^3·667m^-2 and K application of 6.0 kg·667m^-2 and 7.8 kg·667m^-2(CK)at fruit expansion stage(III)and fruit maturity stage(IV),and 3 irrigation deficit levels including sever water deficit(SD),medium water deficit(MD),and light water deficit(LD)with irrigation amount was 40%,60%,and 80%of CK,respectively,and 2 K fertilizer application levels(low K and high K of 60%and 80%of CK,respectively)were set at III and IV stages.The results showed that the diurnal variation trends of photosynthetic index were similar in the two growth stages under different water and K integrated drip irrigation treatments.Under the LD treatment,the net photosynthetic rate(Pn),transpiration rate(Tr),stomatal conductance(Gs),instantaneous water use efficiency(WUEi)and carboxylation rate(CE)of leaves increased with increasing the application amount of K.Pn and CE of III-LDHK are 15.71%and 16.80%higher than that of III-LDLK,Pn and Gs of IV-LDHK were 6.07%and 12.76%higher than that of IV-LDLK,and the difference was significant(P<0.05).Under the SD treatment,except intercellular CO2 concentration(Ci),all photosynthetic indexes decreased significantly compared with CK(P<0.05).Under the MD treatment,except Ci and WUEi,all photosynthetic indexes decreased significantly compared with CK(P<0.05).Under the same K application rate,except Ci and WUEi,the photosynthetic indexes increased significantly with increasing water irrigation(P<0.05),and the increase rate was 11.42%~64.40%.Compared with CK and Pn of III-LDHK treatment increased by 11.38%(P<0.05),WUEi increased by 3.06%;Pn of IV-LDHK increased by 0.96%,WUEi increased by 2.00%.In summary,under III-LDHK and IV-LDHK treatmetns,the photosynthetic capacity of kiwifruit was stronger,and saved the water irrigation and K fertilizer application by 20%at the corresponding growth stage,which was a more suitable integrated management mode of water and K for drip irrigation.