Determination of amino acids from the leaves of evergreen oak (Quercus ilex L.) at four different stages of decomposition

Summary It was established by weak ion exchange resin chromatography that 17 amino acids in proteins and 15 free amino acids account for almost all of the amino acids present in the leaves of evergreen oak (Quercus ilex L.) in four different stages of decomposition. No significant change in the amounts of these amino acids was observed in the course of decomposition. The amino acid content of evergreen oak leaves is comparable to that in pine needles and beech leaves.     

Relationships between sulfur concentration in mulberry Leaves and the quality of silkworm cocoon

A 40-day gnotobiotic microcosm experiment was carried out to quantify the effect of bacterial-feeding nematode on plat growth and nutrient absorption.The results showed that inoculation of bacterial-feeding nematode Protorhabditis sp.stimulated the growth of wheat (Triticum aestivum) and the uptake of N.By the end of the 40-day incubation wheat biomass and N uptake in the treatment with nematode and bacteria (Pseudomonas sp.)increased by 6.5% and 5.9%,respectively,compared with bacteria alone treatment.The presence of nematode mainly accelerated the growth of aboveground of wheat,while it slightly inhibited the root development.There was little difference in plant tissue N concentration between treatments.P concentration and uptake of wheat,however,were generally reduced by nematode, It appears that the enhancement of plant growth and nitrogen uptake is attributed to the enhancement of nitrogen mineraliztion induced by nematode feeding on bacteria,and the reduction of phosphorous uptake is the result of ewak root status and comptetition by bacteria immobilzation.     

Breakdown of azadirachtin A in a tropical soil amended with neem leaves and animal manures

A field investigation was conducted to assess the breakdown of azadirachtin A in a tropical coastal savanna soil amended with neem leaves （NL） combined with poultry manure （PM） or cow dung （CD） using gas chromatography. Samples in polythene bags 15 cm long and 4.8 cm in diameter were randomly placed to a depth of 14 cm in the soil, and azadirachtin A concentration was assessed on days 0, 14, 28, 42, 56, 70, and 84. Azadirachtin A degradation in the soil followed first-order reaction kinetics with different half-lives obtained for varying combinations of the amendments. Higher neem amendment levels of 100 g gave shorter half-lives of azadirachtin A than the lower levels of 50 g. Within the 50 g NL group the additions of the poultry manure and the cow dung gave significantly shorter （P 〈0.05） half-lives of azadirachtin A than the sole neem amendment, whereas in the 100 g NL group only additions of 10 g CD and 10 g PM were significantly less （P 〈 0.05） than the sole neem amendment. Different changes resulting from the kind and quantity of animal manure added were observed in the half-lives of azadirachtin A. The 100 g NL group had significantly higher （P 〈0.05） moisture content, which, coupled with the likely differeaces in microbial biomass, could be the major factor responsible for variations in the half-llfe of the compound. Therefore, the quantity of the neem leaves applied and the addition of animal manure affected the breakdown of azadirachtin A in the soil amended with neem leaves.     

榨菜叶还田对土壤肥力的影响研究

利用盆栽试验和田间试验研究了榨菜叶还田对土壤养分肥力的影响,结果表明,榨菜叶还田处理土壤碱解氮、速效磷、速效钾含量在水稻整个生长期变化较小,水稻生长后期土壤速效N、P、K含量都高于化肥处理;而化肥处理氮磷钾含量变化较大,说明榨菜叶养分供应能够与作物的吸收相互协调,养分供应持续稳定,能满足水稻生长后期对NPK养分的需要,是一种天然的缓释肥料。在水稻生长期,榨菜叶还田能明显的提高土壤肥力,与对照相比,水稻收获后不同处理土壤有机质含量、土壤氮、磷、钾含量,均有所上升,以榨菜叶及其配施化肥处理上升的幅度较大,培肥效果较好。     

银杏叶提取物微胶囊化研究

为使银杏叶提取物能在食品领域得到充分有价值的应用，探索采用微胶囊技术来解决银杏类黄酮难溶于水及强烈苦味的问题。本研究选用阿拉伯胶和β-环状糊精作为银杏黄酮微胶囊壁材，通过喷雾干燥进行微胶囊化。结果表明：选用阿拉伯胶和β-环状糊精(1∶1)作为银杏黄酮的微胶囊壁材，能达到较好的微胶囊化效果，且芯材与壁材的最佳配比为0.1 g/g。最佳喷雾干燥工艺条件为：进料固形物浓度为25％，进风温度为180℃，进料速度为35 mL/min。产品微胶囊化效率达90％以上。     

中国饮茶方式的历史演进

中国饮茶方式历经了由唐以前的生煮羹饮、唐代的煎茶、宋代的点茶到明清瀹饮法的漫漫演进,中国饮茶方式的历史演变也是中华茶文化发展进程的缩影,也是中华茶文化的精华所在。     

橡胶树叶片转化酶提取方法的比较

比较液氮研磨样品与蛋白抽提液研磨样品对6种提取橡胶树叶片转化酶方法的效果。结果表明：液氮研磨法对转化酶活性影响很大，特别是中性/碱性转化酶和细胞壁结合的酸性转化酶已基本失活，而可溶性酸性转化酶活性丧失也比较严重。利用蛋白抽提液研磨样品，用Hepes-NaOH法提取的可溶性转化酶的酶活性最高，达472.44 μmol（glucose）/[g（FW）·h]； 虽然磷酸-柠檬酸法获得的粗酶液的蛋白含量较低， 但其酶活性高达441.61 μmol（glucose）/[g（FW）·h]； Tris-HCl法提取的细胞壁结合酸性转化酶的酶活性最高， 达35.83 μmol（glucose）/[g（FW）·h]。从转化酶的比活力看，磷酸-柠檬酸法最佳，所提取的可溶性转化酶比活力约为Hepes-NaOH法的4倍。本研究结果为进一步完善橡胶树叶片转化酶的提取方法提供重要的指导意义。     

Senescence of Top Three Leaves in Field‐Grown Rice Plants

Abstract

The top three leaves play important roles in biomass production and grain yield of rice (Oryza sativa L.) crop since the three leaves not only assimilate majority of carbon for grain filling during ripening phase, but also provide large proportion of remobilized‐nitrogen (N) for grain development during their senescence. The objectives of this study were to (a) compare senescence of the top three leaves and (b) compare the changes in N, chlorophyll, and ribulose‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco) contents of the top three leaves after their full expansion in field‐grown rice plants. When the basis of comparison among the top three leaves was plant age in terms of days after transplanting (DAT), senescence generally started earliest in ?3rd leaf, intermediate in ?2nd leaf, and latest in flag leaf. If the basis of comparison among the top three leaves was leaf age in terms of days after full leaf expansion (DAFE), it was not clear which leaf senesced earlier. Senescence rate was generally greatest in flag leaf, intermediate in ?2nd leaf, and smallest in ?3rd leaf. Ribulose‐1,5‐bisphosphate carboxylase/oxygenase content declined earlier, and at a faster rate than N and chlorophyll contents during the senescence of all top three leaves. Correlation analysis indicated a close relationship between N and chlorophyll contents. Ribulose‐1,5‐bisphosphate carboxylase/oxygenase content correlated with N content better than with chlorophyll content. The suitability of N, chlorophyll, and Rubisco contents for quantifying the leaf senescence of field‐grown rice plants is discussed.     

海南台农和金煌芒叶片养分周年动态变化分析

对海南主栽芒果品种台农和金煌芒的叶片养分的变化动态进行了分析。结果表明，相同栽培模式下，芒果叶片养分含量在不同品种、不同生长发育阶段和不同物候期之间存在显著的差异，但总体规律为：Ca＞N＞K＞Mg＞P＞Mn＞Fe＞Cu＞Zn。营养生长期间，不同月份芒果叶片中N、P、K、Mg含量基本保持在同一水平上；生殖生长期间，养分从叶片转移至花芽中，叶片养分明显下降。对于大量元素N、P、K、Mg而言，8月份至12月份叶片养分波动较小，因此10月份芒果的叶片可以作为叶片营养诊断的采样时间。     

Macro and trace elements of 26 browse species growing in semi-arid grazing lands of Eastern Cape,South Africa

ABSTRACT

Leaves and twigs from woody plants provide essential nutrients to range animals. We examined variation in the mineral status of 26 woody species, and the influence of harvesting height as well as the interactions of the main effects on minerals levels. Leaves were harvested from five individual plants per species at two height levels: low (<1 m) and upper (>1.5 m). For trees, all mineral levels showed variation (p < 0.05) between species. For shrubs and intermediate growth forms (between shrubs and trees), mineral levels except potassium (K) and zinc (Zn) were influenced (p < 0.05) by height × species interactions. Most browse species had calcium (Ca) contents (8.5–50 g kg^-1) above the required levels, with the majority of the species having Ca beyond the maximum tolerable limit. Most browse plants had sufficient K, phosphorus, magnesium, manganese, iron and Zn concentrations to meet the requirements for ruminants. Copper was deficient in many browse leaves, thus supplementation should be considered in winter. We conclude that such knowledge is essential for sustainable use of browses as mineral supplements, especially during critical periods when climatic conditions limit the feed value of grasses.