关键词: 柠檬, 果实, 品质, 主成分分析, 综合评价, 营养诊断

Abstract:

In the present study，the fruits and leaves from 70 different Eureka lemon orchards in Anyue County of Sichuan Province and Tongliang District of Chongqing were used as experimental materials to determine their main fruit quality parameters and the contents of leaf nutrient elements. The lemon orchards were divided into superior quality and normal orchards based on a established comprehensive evaluation model for lemon fruit quality. The criteria of nutrition diagnosis for Eureka lemon leaves was formulated according to the different grades of orchards. The results showed that four principal components were extracted from the fruit quality principal component analysis with a cumulative contribution of 80.54%. The results of the principal component analysis were used to calculate and rank the overall score of each orchard，which was used as an indicator to classify the orchards. The study of nutrient elements in lemon leaves of different orchards showed that N，K，Zn and B had a normal distribution，while P，Ca，Mg，S，Fe，Mn，and Cu were approximately χ² distributed. The standardized probability grading method was used to divide normally distributed elements into five levels：eficiency，lower，normal，higher，and excess. For elements that did not conform to the normal distribution，the probability classification method was corrected by referring to the nutrient elements in the leaves of superior quality orchards and the existing standard. In conclusion，preliminary standard for the nutrient elements of Eureka lemon leaves was developed.

Key words: lemon, fruit quality, principal component analysis, comprehensive evaluation, nutrition diagnosis