Effect of Liming on the Mineral Nutrition and Yield of Growing Guava Trees in a Typic Hapludox Soil

Abstract: High soil acidity influences the availability of mineral nutrients and increases that of toxic aluminium (Al), which has a jeopardizing effect on plant growth. The objective of this research was to evaluate the effects of soil liming on the development of guava (Psidium guajava L.) plants, on soil chemical characteristics, and on fruit yield. The experiment was carried out at the Bebedouro Citrus Experimental Station, state of São Paulo, Brazil, in a Typic Hapludox soil, from August 1999 to March 2003. The treatments consisted of limestone dose: D₀ = zero; D₁ = half dose; D₂ = total dose; D₃ = 1.5 times the dose, and D₄ = 2 times the dose to raise the V value to 70%. The doses corresponded to zero, 1.85, 3.71, 5.56, and 7.41 t ha^?1 applied to the upper soil layer (0–30 cm deep) before planting. The results showed that liming caused an improvement in the evaluated soil chemical characteristics up to a depth of 60 cm in soil samples both in the line and between lines. The highest fruit yields were obtained when the base saturation reached a value of 55% in the line and 62% between the lines. Foliar levels of calcium (Ca) and magnesium (Mg) were 8.8 and 2.5 g kg^?1, respectively. The highest limestone dose maintained the soil base saturation (at the layer of 0–20 cm) in the line close to 55% during at least 40 months after the incorporation of limestone.     

Clonal propagation of guava （Psidium guajava Linn.） by stem cutting from mature stockplants

Introduction Guava (Psidium guajava Linn.), belonging to the Family Myrtaceae, is originated in the tropical South America (Hayes 1970; Pathak and Ojha 1993) and grows wild in Bangladesh, India, Thailand, Brazil, Florida, West Indies, California and also …     

不同采收期番石榴叶中槲皮素的含量分析

采用回流提取法,以槲皮素的提取率为评价指标,以提取时间、料液比、乙醇浓度和提取次数为考察因素,通过正交试验优化提取条件,并以紫外分光光度法进行定量分析.结果表明,番石榴叶中槲皮素的优化提取条件为90％乙醇(V/V)、料液质量比1∶40、每次提取2h、提取3次;槲皮素含量以3月份最高,达到2.95％.该法测定番石榴叶中槲皮素含量稳定、快速、简便,符合方法学考察要求.     

番石榴叶的化学成分与药理作用研究动态

简述国内外近年对番石榴叶化学成分与药理作用的研究动态,为该作物的应用研发提供有价值的参考。     

番石榴焦腐病菌的ITS分析及PCR检测

番石榴焦腐病是台湾入境大陆水果的重要植物病害,由葡萄座腔菌Botryosphaeria rhodina引起.为建立该病原菌快速、灵敏的检测技术,比较分析了葡萄座腔菌和葡萄座腔菌属其它种的ITS序列,在此基础上设计了1对检测番石榴焦腐病菌的特异性引物BF1/BR1,利用此引物从葡萄座腔菌中特异性扩增出287bp条带,而其余参试的菌株未能获得扩增条带.将真菌通用引物ITS1/ITS4和BF1/BR1进行巢式PCR扩增后,检测灵敏度提高1 000倍,可检测到葡萄座腔菌1pg的基因组DNA.结合快速碱裂解法提取发病组织的DNA,采用该PCR检测技术可从自然感染焦腐病果实中检测到葡萄座腔菌.     

差示分光光度法在番石榴叶总黄酮提取工艺中的应用

[目的]建立番石榴叶总黄酮含量的测定方法,并对番石榴叶总黄酮提取工艺进行优化。[方法]以浓度2％的ZrOCl2·8H2O甲醇溶液为显色剂,测定波长为412nm,以芦丁为对照品绘制标准曲线,建立番石榴叶总黄酮含量的测定方法。在单因素试验的基础上,以总黄酮得率为主要考察指标,干膏收率为次要考察指标,考察料液比、乙醇浓度、提取时间和提取次数对提取效果的影响,并采用正交试验筛选出最佳提取条件。[结果]计算得线性回归方程为：Y=31．3850x-0．0255（R=0．9999）,表明在0～0．024mg／ml范围内,芦丁浓度与吸光度的线性关系良好。优化的提取工艺为：乙醇浓度40％,料液比1：20（g／ml）,提取时间1h,提取次数3次;在此条件下,番石榴叶总黄酮的提取率为3．30％,干膏得率为27．8％。[结论]差示分光光度法操作简单易行、快速、准确,适用于黄酮类化合物的含量测定。通过正交试验优选得到的番石榴叶总黄酮的提取工艺条件稳定可行,对番石榴叶总黄酮的合理开发利用提供理论依据。     

原子吸收光谱法测定番石榴果中微量元素

[目的]建立番石榴果中微量元素的测定方法。[方法]采用火焰原子吸收光谱法测定Cu和Zn的含量,用石墨炉法测定Pb、Cd、Cr、Ni、As和Hg的含量。[结果]所有样品中Cu的含量最高,Zn、Cr、As、Ni、Pb、Cd和Hg的含量次之。火焰法测定Cu和Zn的加样回收率为99.2%~100.4%,石墨炉法测定Pb、Cd、Cr、Ni、As和Hg的加样回收率为97.6%~102.1%,精密度均小于4.46%。[结论]方法简单、快速、灵敏、准确,可用于番石榴果中微量元素含量的测定。     

叶面喷施海藻磷钾肥对金斗香番石榴产量和品质的影响

【目的】金斗香番石榴是广东省农业科学院果树研究所等单位选育的番石榴新品种,通过叶面喷施海藻磷钾肥对其果实品质、产量的影响,为提高金斗香番石榴正造果的产量和品质提供理论依据。【方法】以金斗香番石榴为试验材料,对其叶面喷施不同浓度的海藻磷钾肥,以喷施清水为对照,喷施处理后,统计产量,测定果实质量、横径、纵径、可溶性固形物、可滴定酸、Vc、总糖和蔗糖含量。【结果】海藻磷钾肥可明显促进金斗香番石榴果实生长,提高产量和品质。海藻磷钾肥浓度为1 500倍液时,单果重、果实横径、纵径分别为126.35 g、5.49 cm、5.83 cm,较对照分别增加39.81%、14.85%和14.99%;产量较对照增加35.75%;同时也明显提高了果实品质,Vc、可溶性固形物、总糖和蔗糖含量比对照分别提高20.1%、39.4%、64.3%和72.7%;可滴定酸含量降低14.2%。【结论】叶面喷施海藻磷钾肥提高了金斗香番石榴正造果的单果重、横径和纵径,同时也提高了果实的Vc、可溶性固形物、糖含量,降低了可滴定酸含量。选用海藻磷钾肥1 500倍液效果较佳。     

Changes in nutritional value of guava fruits infected by major post-harvest pathogens

Post-infection changes in ascorbic acid, sugars, proteins and phenols were studied in guava fruits infected by major post-harvest pathogens which in order of importance wereColletotrichum gloeosporioides, (Penz.),Botryodiplodia theobromae, Pat.,Rhizopus arrhizus Fischer.,Phomopsis psidii Nag Raj and Ponnappa apud Ponnappa and Nag Raj, andPestalotiopsis versicolor (Speg.) Steyaert. Contents of ascorbic acid, sugars and proteins declined in the fruits infected byBotryodiplodia theobromae, Colletotrichum gloeosporioides, Pestalotiopsis versicolor, Phomopsis psidii andRhizopus arrhizus. Total phenols increased in fruits infected byPestalotiopsis versicolor andRhizopus arrhizus while reverse was observed in fruits infected by other pathogens.Part of the Ph.D. thesis submitted by the senior author to the Rajasthan Agricultural University, Bikaner.