肉桂山地造林适宜密度的选择

对闽南山地肉桂密度试验的研究结果表明：7a生肉桂不同造林密度间的保存率、树高和胸径存在显著或极显著差异，各器官的单株生物量和林分生物量也差别较大，说明造林密度对肉桂产量的影响极其重要。根据试验结果，提出如下适宜的造林密度：如以收获枝叶提炼桂油和桂通为主要经营目标，主伐年龄5～6a且不间伐的桂子林，适宜的造林密度为6000株／hm^2左右；如以兼收型为培育目标，主伐年龄8～10a的，则适宜的初植密度为4500～5200株／hm^2，且应根据林分长势、林木分化程度等因素，适时进行适量间伐，以期培育优质丰产的肉桂林。     

台湾珍珠芭乐叶面施肥试验

对台湾珍珠芭乐叶面喷施不同浓度的K、Ca和Zn等养分的试验研究，结果表明，叶面喷施养分对台湾珍珠芭乐的产量和质量影响较大，其中以喷施Zn元素的效果为最好，其次为喷施K元素的处理，其最适喷施浓度分别为0．6％硫酸锌和2％硫酸钾。这两个处理不但能明显提高座果率、保果率和产量，分别比对照提高了21．83％、3_4．78％、39．81％和9．43％、18．92％、25．57％；而且能明显增加果实总可溶性固形物含量和维生素C含量，并降低果实酸度，提高果实品质，值得推广应用。     

Antimicrobial activity of Psidium guajava L

Psidium guajava aqueous bark and methanolic extracts were found to possess anti-bacterial activity.     

Pharmacological studies on the leaf of Psidium guajava

The methanol extract of the leaves of Psidium guajava was found to inhibit paw oedema induced by carrageenan in rats and pain induced by acetic acid in mice, and exhibited an antipyretic effect. Oral administration of the extract reduced intestinal transit time and prevented castor oil-induced diarrhoea in mice. A CNS depressant activity was exhibited by the extract by potentiating the phenobarbitone sleeping time in mice.     

Bacteriostatic effect of flavonoids isolated from leaves of Psidium guajava on fish pathogens

The antimicrobial activity against fish bacterial pathogens of flavonoids (morin, morin-3-O-lyxoside, morin-3-O-arabinoside, quercetin, and quercetin-3-O-arabinoside) isolated from the leaves of Psidium guajava was evaluated. The flavonoids were shown to have bacteriostatic effect on all of the tested bacteria.     

Effects of livestock on seed germination of guava (Psidium guajava L.)

This paper reports on the effects that livestock have on seed germination of guava (Psidium guajava L.). Experiments here reported were intended to simulate gastric scarification using different soaking periods in a 0.01 N HCl solution alone or combined with rumen treatments. Additional experiments evaluated germination of defecated and nondefecated seeds germinated in petri dishes and in cow dung.Passage through the digestive tract of cattle did not affect seed germination of guava. Lowered germination was obtained for seeds germinated in cow dung as compared to laboratory germinated seeds. Nevertheless this difference may reflect an inadequate surface-volume ratio of the cow pat used. Large variations in germination between years were recorded. Nothing is known about the effects this may have on the ecology of pasture invasion by guavas.     

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。     

微波辅助水蒸气蒸馏法提取番石榴叶精油

本文开发了一种高效的微波辅助蒸馏法来分离番石榴叶精油的工艺。采用单因素法对该工艺的主要影响因素进行了优化。在优化的条件下,精油的得率为31.76±1.45 mL·kg^-1,获得的番石榴叶精油的主要成分为石竹烯(Caryophyllene)、菖蒲烯A(Calamenene A)、乙酸橙花酯(Nerolidyl acetate)和胡麻烯环氧化物(Humulene epoxide)等。与传统的水蒸气蒸馏法相比,微波辅助水蒸气蒸馏法产量高、耗时短并且耗电少。微波辅助水蒸气蒸馏法被认为是一种潜在的有效的、可持续的从植物基质中分离精油的替代技术。     

Contractile effect of the aqueous extract of Psidium guajava leaves on aortic rings in rat

Aqueous leaves extract of Psidium guajava significantly and dose-dependently (0.25-2 mg/ml) contracted aorta rings. The effect was evaluated also in presence of nifedipine and phentolamine. The sensitivity of the aortic rings to cumulative doses of P. guajava was significantly enhanced in the presence of phentolamine suggesting that the effect of P. guajava was to a large extent mediated by activation of alpha-adrenoceptor and to a lesser extent by acting via calcium ion channel.     

择伐林分冠下造林技术

1造林地选择冠下造林适宜择伐后林分保留木少(一般不足200株 hm2),林内天然更新差,幼苗、幼树少(不足500株 hm2),郁闭度小,立地条件好,土壤湿润易更新等地段。选择造林时,必须做到适地适树的原则。2造林树种选择由于林内光照强度小,通风不良,地表温度低,林内土壤疏松,腐殖质含量高,肥力大,水分充足,因此需要选择幼龄时期有较强的耐阴性、耐湿性,同时又具有很强的可塑性与适应性的树种。在我省东部林区,适宜冠下造林的树种主要有红松、云杉(红皮臭)、水曲柳。现将这些树种的主要的生物学特性和生态学特性简介如下:2 1红松是中性树种,喜深厚肥…     

Pasture growth and floristic composition under the shade of guava (Psidium guajava L.) trees in Costa Rica

Guava (Psidium guajava L.) trees in naturalized, unimproved pastures produce valuable firewood, fruit, shade, and other benefits. The effects of guavas on pasture growth and floristic composition were evaluated. Shaded and non-shaded pastures are floristically very similar. Total growth under shade is 49–63% of that in the open.Axonopus compressus andPaspalum conjugatum were the most prominent grasses in both sun and shade.