Abstract:

【Objective】 To explore the possible impacts of mineral elements and amino acids on rough-skin formation in Korla fragrant pear by comparing the differences o mineral elements and amino acids in rough-skinned fruits and normal fruits. 【Methods】 Inductively coupled plasma mass spectrometry (ICP-MS) and ultra-high performance liquid chromatography-mass spectrometry (UHPLC-MRM-MS/MS) techniques were used to detect the types and contents of mineral elements and amino acids in normal and rough-skinned fruits o Korla fragrant pear fruits collected from 15-year-old pear trees growing in an orchard in Korla (Xinjiang, China). 【Results】 The principal component analysis was carried out on the mineral elements and amino acids. A total of 14 mineral elements and 23 amino acids were detected in different types of fruits of Korla fragrant pear, among which 10 mineral elements and 19 amino acids were differentially accumulated in two types of fruits. In addition to boron (B) and silicon (Si), the contents of the other 8 elements (Na, Mg, P, K, Ca, Mn, Cu) in normal fruits were significantly higher than those in rough-skinned fruits with the fold-changes ranging from 0.70 to 3.17-fold. The contents of 19 differential accumulated amino acids in rough-skinned fruits were significantly higher than those in normal fruits, with the fold-changes ranging from 1.11 to 6.61-fold. Two principal components (PC) were extracted from principal component analysis (PCA) of these 14 mineral elements. Rough-skinned fruit samples and normal fruit samples were separated in the PC plot. Among them, Ca, K and Na had higher PC₁ correlation scores, while Se, Cu and B had higher PC₂ correlation scores. The elements with higher comprehensive scores in both PC₁ and PC₂ were Ca, Mn, K, etc. Similarly, two PCs were extracted from PCA of 23 amino acids, of which 4-hydroxyproline (4-hyp), ornithine (Orn) and histidine (His) had higher PC₁ correlation scores, and serine (Ser), glutamic acid (Glu) and 3-methyl-histidine (3-mehis) had higher PC₂ correlation scores. The amino acids with higher comprehensive scores in both PC₁ and PC₂ were threonine (Thr), alanine (Ala) and 4-Hyp. 【Conclusion】 The mineral elements and amino acids were differentially accumulated between two types of fruits. Differential accumulation of the mineral elements (Ca, Mn and K) and amino acids (Thr, Ala and 4-Hyp) with higher comprehensive scores might be one of the main reasons for the phenotypic differences between the rough-skinned and normal fruits.

Key words: Korla fragrant pear; rough-skinned fruits; mineral elements; amino acids; principal component analysis

摘要：

【目的】 研究比较库尔勒香梨粗皮果和正常果中矿物质元素和氨基酸的差异,分析库尔勒香梨粗皮病与矿物质元素和氨基酸的关系。【方法】 以库尔勒地区15 a生的香梨树为材料,分别利用电感耦合等离子体质谱(ICP-MS)和超高效液相色谱-质谱联合分析(UHPLC-MRM-MS/MS)技术检测库尔勒香梨正常果和粗皮果果实中的矿物质元素和氨基酸的种类和含量,运用主成分分析法对其分析。【结果】 库尔勒香梨不同类型果实中共检测出14种矿质元素和23种氨基酸,其中10种矿物质元素和19种氨基酸在不同类型果实中差异性积累。10个差异矿物质元素里除了硼(B)和硅(Si),其余8个元素(钠(Na)、镁(Mg)、磷(P)、钾(k)、钙(Ca)、锰(Mn)、铜(Cu))在正常果中含量明显高于粗皮果,矿物质在不同类型果实中的差异倍数为0.70~3.17倍。而19种差异氨基酸在香梨粗皮果中的含量显著高于正常果实,氨基酸在不同类型果实的差异倍数为1.11~6.61倍。在不同类型果实矿质元素中提取2个主成分,其中主成分1(PC₁)中Ca、K、Na等元素的分数较高,主成分2(PC₂)中Se、Cu、B等元素的分数较高,PC₁和PC₂中综合得分较高的元素为钙Ca、Mn、K等元素;针对不同类型果实种23种氨基酸进行主成分分析共提取2个主成分,其中PC₁中4-羟脯氨酸(4-Hyp)、鸟氨酸(Orn)、组氨酸(His)等的分数较高,PC₂中丝氨酸(Ser)、谷氨酸(Glu)、3-甲基-组氨酸(3-MeHis)等得分数较高,在PC₁和PC₂中苏氨酸(Thr)、丙氨酸(Ala)、4-Hyp等氨基酸的综合得分较高。【结论】 库尔勒香梨不同类型果实中矿物质元素和氨基酸含量具有显著差异,矿物质元素中的Ca、Mn、K和氨基酸中的Thr、Ala、4-Hyp综合的分数较高,其含量的差异可能是导致两种果实差异的原因。

关键词: 库尔勒香梨, 粗皮果, 矿物质元素, 氨基酸, 主成分分析