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Chapter 1. Nutrient Uptake and Transport Capacities of Different Mango RootstocksSummary The objectives of thisexperiment were to investigate the mango cultivars'' abilities in the uptake and transport of mineral nutrients with special emphasis on the selection of a high Ca absorbing rootstock . The data will also be used as a guideline for the choosing of a rootstock for Chiin Whang which is a deficiency─prone cultivar and to clarify the relationship between Ca deficiency and pre harvest fruit deterioration. Results showed a significant difference in Ca content in leaves among cultivars. Caltivars were arranged according to the Ca concentration in leaves (from high to low) after calcium fertilizer was applied. They were listed as Local Varity, Tai-Known No.1, Keitt, Haden, Phon-Mee, Chiin Whang, Hon-Long, Irwin and Sensation. The order in the control was Local Varity, Tai-Known No.1, Phon-Mee, Haden, Hon-Long, Keitt, Irwin, Chiin Whang and Sensation. Calcium concentration from high to low in leaves of Chiin Whang after grafting were in the following order: Hon-Long, Tai-Known No.1, Local Varity, Sensation, Keitt, Haden, Chiin Whang and Irwin. After pruning the order were:Local Varity, Tai-Know No.1, Keitt, Sensation, Hon-Long, Haden, Chiin Whang and Irwin. The magnitude of leaves calcium concentration of cultivars planting in field were Tai- Known No.1, Hon-Long, Local Varity , Haden, Sensation, Irwin and Chiin Whang.The N/Ca of Irwin, Keitt and Chiin Whang leaves was higher than the other cultivars. Since the above mentioned cultivars are sensitive to Ca-deficiency, the pre harvest fruit deterioration may be associated with a high N/Ca in leaves. Results also indicated that Local Varity and Tai-Known No.1 had higher Ca uptake and transport capacities. Thus, It is suggested that these cultivars could be adopted as rootstocks in the cultivation and breeding of Chiin Whang mango.Chapter 2. Relationship between Stomata Density, Leaf and Fruit Nutrient ConcentrationSummary Eight mango cultivars grown in three different locations were used in the determination of leaf and fruit mineral nutrient concentrations and the possible relations between them. Stomata density was recorded with a view to elucidating the relationship between transpiration and Ca uptake. Result indicated ''Chiin Whang'' mango had the highest N content among cultivars in all three locations. A comparasion of the average leaf nutrient concentration of the 8 cultivars with that of Florida, U.S.A. revealed that Ca was rather low, a slight variation in N but no significant differences were found for the other nutrients. Ca decreased as fruits were measured from proximal to the distal end, or from peel to the inner mesocarp. In the different portion of fruit, N was the lowest at outer mesocarp, P was the highest at distal end and K was the highest in the inner mesocarp. High K and Cu were found accumulated in the fruit at the fruit developmental stage. But high N, P, Mg,Ca, Fe, Mn and B were found in leaves.In both leaves and fruits, experiment results showed a negative correlation between P and Ca, K and Zn, Zn and Fe, Cu and Mn. However, K and Mn, Mg and Cu, Mn and Mn. Zn and Zn, Zn and B exhibited a positive relationship. Boron and Cu likewise showed unveiled a positive correlation between leaf and leaf. A positive correlation was also observed between P and N, Mg and K, Cu and Zn together with a negative relationship between B and Fe. A high value of N/Ca, K/Ca and Mg/Ca could be associated with fruit deterioration. Results indicated Deshehari, Israel and Man-Moo had more stomata numbers than those of Irwin, Sensation and Haden. A positive correlation was noticed between the distribution of stomata and Ca uptake.Chapter 3. Leaf Carbohydrate and Mineral Concentrations of seedling, Scion and Rootstock of ''Chiin Whang'' mangoSummary An experiment was carried out using tips of juvenile twig and were grafted on the mature rootstock to induce flower bud differentiation. After successful grafting and further growth, leaves of seedling, topworking scion and rootstocks were sampled and analyzed for carbohydrate, mineral nutrients and C to N ratio. Results indicated that carbohydrate concentration of seedling was rather stable while those of topworking scion and rootstock increased rapidly to 30% in March a two-fold increase from October. No difference was found in soluble sugar content at the early developmental stage. Soluble sugar swiftly increased in the topworking scion and rootstock during the flowering period in March. Starch content was high in seedlings while that of the rootstock was low with scion in between. A significant decline was observed at the sampling time in October. As to element concentrations, Seedling had a high P level as well as Mn and Cu. Rootstock had relatively lower value of P and Cu as compared with the seedling and scion. No definite trend was found for the other elements. Results also indicated seedling leaves had a higher value than scion and stock at the beginning of investigation. Carbon to Nitrogen ratio in leaves of topworking scion and rootstock augmented during blossom in March to 21.6 and 21.9, respectively, and had a similar trend in the changing process, lowest in October and hit an all-time high in March.It is concluded that the basis of inducing flower initiation in seedling after grafting could be the effect of carbohydrate alone as shown by the significant change in C to N ratio.
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