The study and investigation of affected factors on physiological disorder syndromes of longan peel skin (Dimocarpus longan Lour. Var. Daw) at Ban Phu Din, Mae Taeng District, Chiang Mai Province, was investigated by using B and Zn treatments on concentrations (w/w) at 0% (T1), 0.1%B (T2), 0.2% B (T3), 0.1% Zn (T4), 0.2% Zn (T5), 0.1% B + 0.1% Zn (T6) and 0.2% B + 0.2% Zn (T7) during the growth period of longan on 0, 8, 16, 24 and 28 weeks, respectively. Physical changes on preharvest and postharvest study, protein changes on proteomics and metabolite changes on metabolomics were applied to analyze relation with disorder expression.
After foliar application, the physical and chemical properties studies (sub-project 1) were found that in the first month, control had more fruit set per bunch than another treatment (40.80 fruits) was significantly difference .Fruit quality was found that the foliar application of zinc and boron treated fruits, fresh weight had significant higher flesh weight and fruit weight per bunch compared to the control. Whereas, the width and length of fruit, total soluble solid, peel weight, seed weight did not significant difference .However, peel color showed that fruit treated with 0.29 boron and 0.2 zinc foliar application were clearly green and bright yellow when the harvesting stage and was significantly difference compared to others treatments. Application of B and Zn foliar sprays at gave higher Zn/B accumulated in the leaves which was more than the standard values of normal/control longan leaves .It was shown that the B and Zn foliar application can be leaves absorb and acuminated to use in the enough on growth stage during and development.
The physical and chemical results (sub-project 4) showed that group T7 had the maximum fruit weight, fruit size (width, length, and diameter) of 12.21 g, 3.20 cm, 2.74 cm, and 2.60 cm, respectively. On the other hand, the group T3 fruit had yielded the lowest average fruit weight and fruit size (width, length, and diameter) of 9.20 g, 2.62 cm, 2.40 cm, and 2.40 cm, respectively. The red color (a) of the peel of group T3 was the highest at 11.26. The lightness (L) of the peel (50.79-52.98) and flesh (35.88-38.92), total soluble solids (TSS) (20.01-20.44 %Brix), titratable acidity (citric) (1.08-1.49 g/100g), and pH (6.62-6.73) were not significantly different among the various treatment groups. The sensory evaluation of longan fruit found that at group 3 had the lowest sensory score of appearance, color, taste, aroma, texture and overall acceptable and significantly different among treatments.Protein separation (sub-project 2) by using one dimensional electrophoresis (1-D gel) of 80 ?g proteins in reducing sample conditions at 12.5% gel staining with Coomassie brilliant blue R-250 indicated that the 18.60 kDa of protein band in gel expression (vegetative storage protein, 25.17 kDa) was decreased in groups receiving boron and zinc foliar application Additionally, it indicated that the 20.83 kDa (vegetative storage protein) of protein band expression of longan peel was decreased in group receiving boron and zinc treatment (T7) compared to the same band from group T1 which showed the physiological disorder on the peel group of physiological disorder syndromes of longan peel skin (T1) throughout the 4 months after fruiting. This result had accordance with the decreased red value (a) of the longan peel. The results of Western blotting techniques are unclear due to problems with the antibodies being used. Therefore, further improvements are needed.
The analysis of the metabolomics of leaves (sub-project 3) by using LC-MS techniques showed that the total ion chromatogram (TIC) in terminal phase was disturbed by leaf binding agents and surfactants. Therefore, it is unable to interpret the LC-MS dataset to facilitate the search for the cause of the physiological disorder syndromes. Therefore, the study of metabolite biomarker in longan peel were conducted from metabolites from longan peels of the 0.2% w/w zinc (T6) and physiological disorders (T1). It found that 2 substances (6-(Hydroxymethyl)-2,4(1H,3H)-pteridinedione, and intermediate in folate biosynthesis and ?-aminoheptanoic acid, and inducer on immunity to resist infection) significantly increased (q <0.05) in T6 group at 1 month after fruiting. However, there were in 2 substances, 6-methyl thiohexylhydroximoyl-glutathione and trihomomethionine decreased and were consistent with the reduction of boron and vegetative storage proteins on zinc treatment in proteomic studies
Keywords: Longan peel skin, zinc, boron, metabolomics, proteomics, physiological disorders