Effects of foliar spraying K2SO4 on sugar metabolism in ‘Ruixue’ apple fruit
View Fulltext  View/Add Comment  Download reader
  
DOI:10.7606/j.issn.1000-7601.2024.02.11
Key Words: ‘Ruixue’ apple  potassium  foliar spraying  sugar metabolism  fruit quality
Author NameAffiliation
JIA Rongjian College of Horticulture,Northwest A&F University, Yangling, Shaanxi 712100, China 
HU Yu College of Horticulture,Northwest A&F University, Yangling, Shaanxi 712100, China 
YANG Jie College of Horticulture,Northwest A&F University, Yangling, Shaanxi 712100, China 
HE Ying College of Horticulture,Northwest A&F University, Yangling, Shaanxi 712100, China 
MA Yongtao College of Horticulture,Northwest A&F University, Yangling, Shaanxi 712100, China 
WANG Yuanji College of Horticulture,Northwest A&F University, Yangling, Shaanxi 712100, China 
ZHAO Zhengyang College of Horticulture,Northwest A&F University, Yangling, Shaanxi 712100, China 
Hits: 3
Download times: 3
Abstract:
      To explore the effects of spraying different concentrations of foliar potassium fertilizer on the fruit quality of apple variety ‘Ruixue’, the most suitable concentration of potassium fertilizer for ‘Ruixue’ was determined. Four\|year\|old ‘Ruixue’ was used as the experimental material.The type of foliar potash fertilizer was K2SO4, and three concentration gradients were set as T1 (0.1%), T2 (0.3%) and T3 (0.5%), respectively. Spraying clear water was used as control (CK). Foliar potash fertilizer was divided into 5 stages, the first fertilization time was May 22 (38 days after bloom), and then sprayed every other month. Fruit samples were collected at 45, 75, 105, 135 d and 180 d after anthesis, respectively. The indexes of sugar components, activities of enzymes related to glucose metabolism and basic fruit quality were determined. The results showed that compared with the control, the treatment group (T1, T2, T3) significantly improved the fruit quality of ‘Ruixue’, which was 12.6%, 25.9% and 4.4% higher than CK, respectively; the fruit firmness of the treatment group was 7.7%, 29.6% and 12.1% higher than that of CK, respectively; and the soluble solid content of the treatment group was significantly increased by 1.14, 1.95 and 0.87 percentage points, respectively. The titratable acid content in the treatment group was significantly reduced by 0.04, 0.05 and 0.09 percentage points, respectively (P<0.05). Among them, the single fruit weight, firmness and soluble solids of T2 treatment were the highest, the mass of single fruit was 335.75 g, the firmness was 9.82 kg·cm-2, and the content of soluble solids was 16.35%. The titratable acid content of the fruit treated with T3 was the lowest, and the content was 0.19%. Potassium application significantly increased the contents of N, P, K, Ca, and Mg in leaves, and significantly increased the contents of N, K, Ca, and Mg in fruit, but the content of P in fruit did not increase significantly. After T2 treatment, the contents of fructose, sucrose and glucose in mature fruits increased significantly, increased by 35.54%, 33.22% and 25.31% respectively compared with CK. Potassium increased the activities of acid invertase (AI), sorbitol oxidase (SOX), sorbitol dehydrogenase (SDH) and sucrose synthase (SS) in fruits. At 180 days after anthesis, the activities of AI, SOX, SDH and SS in T2 treatment increased by 4.54%, 2.08%, 19.11% and 12.81% respectively compared with CK. In terms of correlation analysis, there was an extremely positive correlation between potassium application rate and glucose content in fruit at 45 days and 75 days after anthesis (r45DAB=0.879**, r75DAB=0.893**), and an extremely significant negative correlation with sorbitol content at 180 days after anthesis (r180DAB=-0.861**). There was an extremely significant positive correlation between potassium application rate and neutral invertase activity in fruit at 135 days after anthesis (r135DAB=0.763**), an extremely significant positive correlation with sorbitol oxidase activity at 45 days and 75 days after anthesis (r45DAB=0.717**, r75DAB=0.880**), and an extremely significant positive correlation with sucrose synthase activity at 180 days after anthesis (r180DAB=0.739**). The most suitable concentration of K2SO4 fertilizer sprayed on the leaves of ‘Ruixue’ apple was 0.3% (T2), which could significantly improve the fruit yield and quality.