四季柚生育期叶片和果实中矿质元素含量变化的研究

本研究以四季柚为试材，定期测定果实发育周期内叶片与果实的矿质元素含量，研究四季柚叶片和果实矿质养分需求特征与相关性，为树体营养科学调控，优质高效施肥提供理论依据。结果显示，叶片生长过程中N、 P元素含量呈逐渐下降趋势，K、 Ca、 Mg、 B、 Zn含量呈先增后降趋势，S含量总体保持上升趋势，Fe含量呈现先降后稳再上升趋势，Cu含量总体较稳定，Mn含量呈现出先上升后下降再上升趋势; 果实生长过程中，N、 P、 K、 Ca、 S含量呈下降趋势，Mg含量呈现先升后降的趋势，微量元素中Fe、 Mn元素含量变化幅度较小，B、 Zn、 Cu元素含量变化趋势略有不同。叶片与果实之间矿质元素协同吸收作用较弱，而果实与果皮之间作用较强。研究表明，萌芽前应适当增施氮、 磷肥，6月中旬增施钙肥，7月中旬增施钾肥和镁肥，以及重视微量元素肥料的应用。

Variations of mineral elements contents in Sijiyou pummelo leaves and fruits during the development period

As an important part in fruit cultivation, fertilization becomes one of the most effective technologies to improve yield and quality of fruit. Combination with plant nutrition diagnostic techniques, the theory of mineral nutrition with fertilization techniques on fruit production was applied to understand surplus deficit status of nutrient elements at fruit growth period of Sijiyou pummelo ［Citrus grandis (L.) Osbeck］ and to provide theoretical basis for the nutritional regulation and rational fertilization application. The contents of mineral elements in Sijiyou pummelo leaves and fruits at the fruit development period were measured to study their variation characteristics and correlations. The research was carried out in plants of over 40 years old in Sijiyou pummelo production base in Zhejiang province since 2009 The results show that during the development of leaves, the N and P contents decreased gredualy, the K, Ca, Mg, B and Zn contents increased in the early phase and decreased later, and the S content increased on the whole. The Fe content decreased gradually in the early phase, then steady, and increased later. The Cu content vept stable, and the content of Mn increased and then decreased, and finally increased. In the development of fruits, the N, P, K, Ca and S contents present downward trends all along, the Mg content increased at the early phase and decreased later, the Fe and Mn contents kept relatively stable, and the contents of B, Zn and Cu slightly different at the development period. The level of collaborative absorption of mineral elements was week between fruits and leaves, but strong between flesh and peel. Relatively high N and P fertilizer rates should be used before the budding, proper amount of Ca fertilizer in mid-June, K and Mg fertilizers in mid-July should be applied, and microelements fertilizer application should be emphasized.