大红火龙果果实养分积累量动态变化及其相关性

【目的】分析海南地区大红火龙果果实生长规律和养分积累量动态变化及其相关性，为火龙果科学施肥提供理论依据。【方法】以大红火龙果谢花后8、16、24和32 d 4个不同生育期的果实为材料，测定果实横纵径、干重等农艺性状和氮（N）、磷（P）、钾（K）、钙（Ca）、镁（Mg）等矿质养分积累量指标，探索大红火龙果果实的形成规律和矿质养分动态变化，并分析果皮与果肉矿质养分间的相关性。【结果】果实发育前期（谢花后前24 d）主要为干物质积累，生长高峰期在谢花后16~24 d，横纵径和含水量的增长率较大。果实发育后期（谢花后24~32 d）果皮干重减少，主要为果肉增重与转色。随着火龙果的生长发育，果肉中的矿质养分积累量总体呈上升趋势，果皮和整个果实中的矿质养分积累量总体呈先上升后下降的变化趋势，果实对N、K和Ca的需求量较大，果皮和果肉之间K、Ca、Mg、硫（S）、铁（Fe）、铜（Cu）、锌（Zn）和硼（B）8种元素相互之间分别呈显著（P<0.05，下同）或极显著正相关（P<0.01，下同），果皮锰（Mn）与果肉Mn和Cu元素呈显著正相关，与果肉Zn和B元素呈极显著正相关，Mn与其他元素间无显著相关性（P>0.05）。整个生育期果皮矿质养分积累量排序为K>N>Ca=Mg>P>S>Fe>Mn>Zn>B>Cu，果肉矿质养分积累量排序为K>N>Mg>Ca>P>S>Fe>Mn>Zn>B>Cu，果实矿质养分积累量排序为K>N>Mg>Ca>P>S>Fe>Mn>Zn>B>Cu。【结论】大红火龙果生长发育前期（谢花后前24 d）主要为果实膨大，应加强N肥的施用和水分管理；发育后期（谢花后24~32 d）主要为果实转色，应注重K肥和Ca肥的施用，根据土壤肥力状况适当补充Mg、B等微量元素肥料。

Dynamic changes and correlation of nutrient accumulation in the fruit of red pitaya

【Objective】 In order to understand the development and growth of the red pitaya fruit and the dynamics of nutrient accumulation and their correlation in Hainan, to provide a theoretical basis for scientific fertilization of pitaya in this area.【Method】 Using the four different growth stages of the red pitaya at 8, 16, 24, and 32 d after flowering, the agronomic traits such as the horizontal and vertical diameters and dry weight of the fruit and nitrogen(N), phosphorus(P), potassium(K), calcium(Ca) and magnesium(Mg). Explored the formation law and dynamic changes of mineral nutrients of red pitaya fruit, and to analyze the correlation between peel and pulp mineral nutrients.【Result】 The early stage of fruit development(the first 24 d after flowering) was mainly the accumulation of dry matter. The peak growth period was 16 to 24 d after flowering, and the growth rate of horizontal and vertical diameter and water content were large. In the later stage of fruit development(24-32 d after flowering), the dry weight of the peel was reduced, mainly due to the weight gain and color change of the pulp. With the growth and development of pitaya, the mineral nutrient accumulation in the pulp showed an overall upward trend, and the mineral nutrient accumulation in the peel and the whole fruit showed an overall upward trend and then a downward trend. The fruit's demand for N, K, and Ca was high. The eight elements of K, Ca, Mg, sulfur(S), ferrum(Fe), copper(Cu), zinc(Zn), and boron(B) between the peel and the pulp had significant(P<0.05, the same below) or extremely significant positive correlation with each other(P<0.01, the same below). There was significant positive correlation between peel manganese(Mn) and pulp Mn and Cu, and extremely significant positive correlation with Zn and B elements, but there was no significant correlation between Mn and other elements(P>0.05). The accumulation of mineral nutrients in the whole growth period of the peel was K>N>Ca=Mg>P>S>Fe>Mn>Zn>B>Cu, and the accumulation of mineral nutrients in the whole growth period of the pulp was:K>N>Mg>Ca>P>S>Fe>Mn>Zn>B>Cu, the accumulation of mineral nutrients throughout the fruit growth period was:K>N>Mg>Ca>P>S>Fe>Mn>Zn>B>Cu.【Conclusion】 The early stage of red pitaya growth(the first 24 d after flowering) and development is mainly due to the expansion of the fruit, and attention should be paid to the application of N fertilizer and water management. The late stage of pitaya development(24-32 d after flowering) is mainly for the color change of the fruit. The application of K fertilizer and Ca fertilizer should be paid attention to, and the supplement of trace element fertilizers such as Mg and B should be conducted based on soil fertility.