钾肥对干旱胁迫下马铃薯生理特性、产量及品质的影响

Effect of Potassium Fertilization on Physiological Characteristics,Yield and Quality of Potato under Drought Stress

为探究干旱胁迫下不同施钾水平对马铃薯生长、光合荧光参数、抗性生理以及产量品质的影响,以‘陇薯7号’为研究对象,采用盆栽控水法进行干旱胁迫,钾肥用量分别为0 g/株(CK)、1.5 g/株(T1)、3.0 g/株(T2)、4.5 g/株(T3)、6.0 g/株(T4),共5个处理,并进行相关性与主成分分析。结果表明:干旱胁迫下施钾有利于马铃薯植株生长,增加株高和茎粗,以T2处理效果最佳;叶绿素a+b含量、净光合速率(P_(n))、气孔导度(G_(s))和蒸腾速率(T_(r))亦在T2处理最高,分别较CK增加22.50%、62.30%、27.66%和37.98%,而胞间CO_(2)浓度(C_(i))最低;施钾也可以提高马铃薯叶片的最大量子效率(Fv/Fm)、光化学猝灭系数(qP)、非光化学猝灭系数(N_(PQ))和脯氨酸(Proline)含量,降低热耗散量子比率(Fo/Fm)和丙二醛(MDA)含量,其中以T2和T3处理效果最明显;同时,施钾处理提高超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性;T1、T2、T3和T4与CK相比分别增产14.80%、36.38%、24.98%和9.77%,其中T2产量最高,达35209.06 kg·hm^(-2);施钾显著提高干旱胁迫下块茎中淀粉、蛋白质和维生素C含量,T2处理提升效果最优,同时降低还原糖含量,其中T3处理还原糖含量最低。相关性分析结果表明,马铃薯产量与叶片P_(n)显著正相关,淀粉与叶片G_(s)显著正相关。依据主成分得分排序,不同水平钾肥对干旱胁迫的缓解能力为T2>T3>T1>T4>CK。因此,T2处理可更好促进干旱胁迫下马铃薯的生长,增强叶片光合荧光特性、抗氧化能力,减缓叶片衰老速率,进而提高产量改善品质,缓解干旱胁迫的不利影响。

To investigate the effect of varying potassium levels on potato growth,photosynthetic fluorescence parameters,physiological resistance,yield,and quality under drought stress,‘Longshu 7’was utilized as the research subject.Drought stress was induced using potted plants with controlled water supply,and different potassium fertilizer dosages were applied:0 g/plant(CK),1.5 g/plant(T1),3.0 g/plant(T2),4.5 g/plant(T3),and 6.0 g/plant(T4).Correlation and principal component analyses were conducted the findings of the study indicated that applying potassium during drought stress had a positive effect on potato plant growth.Specifically,it resulted in increased plant height and stem thick,and T2 treatment showed the most significant effect.Additionally,the T2 treatment exhibited the highest levels of chlorophyll a+b content,net photosynthetic rate(P_(n)),stomatal conductance(G_(s)),and transpiration rate(T_(r)).These parameters increased by 22.50%,62.30%,27.66%,and 37.98%,respectively,compared to the CK.Conversely,the intercellular CO_(2) concentration(C_(i))was the lowest in the T2 treatment.Potassium application enhanced several important parameters in potato leaves.This included an increase in maximum quantum efficiency(Fv/Fm),photochemical quenching coefficient(qP),non-photochemical quenching coefficient(N_(PQ)),and proline content.It led to a reduction in thermal dissipation quantum ratio(Fo/Fm)and malondialdehyde(MDA)content.Among the treatments,the T2 and T3 treatment exhibited the most noticeable effects.Moreover,the application of potassium also improved the activities of superoxide dismutase(SOD),peroxidase(POD),and catalase(CAT).Compared to the CK,T1,T2,T3 and T4 treatments increased the yield by 14.80%,36.38%,24.98%,and 9.77%,respectively.The highest yield was achieved in the T2 treatment,reaching 35209.06 kg·hm^(-2).The potassium application had a significant positive effect on the starch,protein,and vitamin C contents of the tubers under drought stress.Among the treatments,the T2 treatment exhibited the most effective improvement and resulted in a reduction of reducing sugar content.It is worth mentioning that the lowest reducing sugar content was observed in the T3 treatment.The correlation analysis revealed significant positive correlations between potato yield and leaf P_(n),as well as between starch content and leaf G_(s).Based on the ranking of principal component scores,the effectiveness of different levels of potassium fertilizer in alleviating drought stress was T2>T3>T1>T4>CK.Therefore,T2 treatment exhibits the highest potential in enhancing potato growth under drought conditions,improves leaf photosynthetic fluorescence characteristics,antioxidant capacity,and decelerates leaf aging rate.As a result,it improves yield and quality,effectively mitigates the adverse effects of drought stress.