In vitro Culture of Abscissed Immature Avocado Embryos

The efficiency of an avocado hybridization programme, usingsmall potted glasshouse plants, was reduced by a high rate ofabscission of immature fruitlets bearing embryos too young forconventional germination. This was overcome in part by culturein vitro of the shed embryos on a liquid medium supplementedwith 0.5 mg l^–1 benzyladenine. Most embryos younger than6 weeks did not survive in culture, but older embryos slowlyproduced multiple shoots, with axillary shoot growth being furtherstimulated by removal of both cotyledons. Embryo response wasnot related to cultivar. Shoots removed from culture could begrafted to seedling rootstocks. Grafting was considered morereliable than dependence on growth of the main root or adventitiousroots in vitro to produce established plants. Persea americana Miller, avocado, abscissed fruitlets, in vitro embryo culture     

长沙市春季时尚花卉调查与初步研究

研究表明,长沙市2004年春季时尚花卉有79种,涉及45科52属.其中主要种类有蝴蝶兰、巴西铁、金琥、红星果子蔓、圣诞花、金桔等30种,涉及15个科,28个属,包含观花、观叶、观茎、观果和观赏苞片类等5大类,其中以观叶类和观花类花卉占大多数,二者分别占38.7%和32.2%.对重要花卉种类的形态特征、栽培要点及观赏特点等进行了描述,分析了其中15种重要时尚花卉的观赏特色和人气指数,对近年来大众花卉消费观念的变化进行了分析,预测了未来花卉的消费趋势.对我省花卉消费市场及花卉产业发展等问题进行了讨论,提出了有益的建议.     

Anatomy and Transpiration of the Avocado Inflorescence

Structure and function of the inflorescence of cv. 'Hass' and'Fuerte' avocado (Persea americana Mill.) were examined by scanningelectron microcopy (SEM) and by porometry. Sepals and petalscould not be distinguished by their position in the flower,by visual gross morphology or by microscopic surface structureand were hence designated as tepals. These tepals were arrangedin two whorls of three, followed by two whorls of three outerand three inner stamens, each opposite a tepal. The most conspicuousfeature of tepals, developing leaves and peduncles was the densecover of hair which were most frequent on the adaxial tepalsurface (925-1200 trichomes mm^-2), followed by their abaxialsurface (625-1000 mm^-2) and peduncles (375-655 mm^-2). Stomatawere absent from the adaxial surfaces of both tepal and leaves,as well as peduncles. On the tepals, abaxial stomata appearedfunctional, small (8-9 x 11-13 µm) and scarce with 2·8-3·4stomata mm^-2, i.e. very low relative to avocado leaves (350-510stomata mm^-2) or young fruit (50-75 stomata mm^-2. However, flowersincluding tepals transpired 1·2-1·3 mmol underfield conditions in Southern California (1·6-2 kPa),i.e. in excess of leaves (0·7-1·1 mmol) and peduncles(0·6-0·8 mmolH₂O m^-2 s^-1). This situation wasattributed to the few small but functional abaxial stomata onthe tepal, in contrast to 80% closed stomata and dense epicuticularwax cover in form of rodlets on young and dendritic crystalson old leaves including the guard cells, and absence of stomatafrom the peduncle.Copyright 1993, 1999 Academic Press Persea americana Mill., avocado, bioenergetics, flower, fruit, leaf, peduncle, scanning electron microscopy, stomata, transpiration, petals, sepals, tepals     

The Fine Structure of Avocado Plastids

Ultrastructural studies of both young and harvest-ripe avocadofruits have established that the skin and outer green layersof flesh contain chloroplasts with an extensive thylakoid system.Etioplasts occur in the yellow flesh adjacent to the stone.The pale-green flesh contains plastids, intermediate betweenchloroplasts and etioplasts, which have prominent prolamellarbodies from which radiate grana. When segments of both the yellow and pale-green flesh of maturefruit (7 cm diam.) are cultured in the light their prolamellarbodies do not disperse although there is a change in their crystallinity.The palegreen tissues of immature (4 mm and 2 cm diam.) fruitsalso contain etioplasts but on culturing these differentiateinto chloroplasts. Both chlorophyll content and the ratio ofchlorophyll a to b varied in the different tissues of youngand mature fruits.     

鳄梨油在化妆品中的应用及配方

本文对鳄梨油的化学成分、生物活性及美容化妆品配方进行概述。     

Acid Phosphatase Development during Ripening of Avocado

The activity and subcellular distribution of acid phosphatase were assayed during ethylene-induced ripening of whole fruit or thick slices of avocado (Persea americana Mill. var. Fuerte and Hass). The activity increased up to 30-fold during ripening in both the supernatant fraction and the Triton X-100 extract of the precipitate of a 30,000g centrifugation of tissue homogenates from whole fruit or slices ripening in moist air. Enzyme activity in the residual precipitate after Triton extraction remained constant. The development of acid phosphatase in thick slices ripened in moist air was similar to that in intact fruit, except that enzyme development and ripening were accelerated about 24 hours in the slices. The increase in enzyme activity that occurs in slices ripening in moist air was inhibited when tissue sections were infiltrated with solutions, by aspiration for 2 minutes or by soaking for 2 hours, anytime 22 hours or more after addition of ethylene. This inhibition was independent of the presence or absence of cycloheximide or sucrose (0.3-0.5m). However, the large decline in enzyme activity in the presence of cycloheximide, as compared with the controls, indicated that synthesis of acid phosphatase was occurring at all stages of ripening.     

Inhibitor and Auxin Activity in the Avocado Fruit

The wheat coleoptile elongation bioassay was used for determination of growth-promoting and growth-inhibiting substances in avocado (Persea americana Mill.) fruit tissues, during development and maturation. Growth-promoting activity was found in two zones on paper chromatograms developed with isopropanol: ammonia : water (10:1:1 v/v): Rf 0.30–0.50 and Rf 0.8–0.9. Growth inhibiting activity was found in three different zones: “A” Rf 0.0–0.2, “B” (abscisic acid) Rf 0.6–0.8, and “C” (l-acetoxy-2,4-dihyroxy-n-hepta-deca-16-ene) Rf 0.85–1.0. Higher levels of auxins were found in seed tissues than in the mesocarp. No correlation was found between fruit growth rate and level of extractable auxins in the mesocarp. The amount of abscisic acid (ABA) in the mesocarp was constant during fruit growth. A gradual and consistent increase in 1-acetoxy-2,4-dihydroxy-n-hepta-deca-16-ene was found during fruit growth, reaching a maximum when the fruit attained maturity.     

Stereoselectivity of Abscisic Acid-oxygenase in Avocado Fruits

The optically resolved (±)-dihydrophaseic acid (DPA) was achieved by using a commercially available chiral HPLC column. PA and DPA, which were isolated after feeding (±)-(RS)- [²H6]-ABA to avocado fruits, were analyzed by the chiral HPLC method to examine the stereoselectivity of the oxygenase. Small peaks of the unnatural enantiomer could be observed in each case. The results show convincingly that (–)-(R)-ABA was converted to PA and DPA, although the extent of this conversion is very small in comparison with the conversion of (+)-(S)-ABA.     

高黎贡山花卉资源与赏花旅游初探

高黎贡山有完整的生物气候垂直带谱自然景观,多种植被类型和丰富的植物资源,目前已知有种子植物2门210科1086属4303种及变种,其中有较高观赏价值的花卉达62科320属1053种,是我国花卉资源最丰富的地区之一。高黎贡山花卉资源具有种类丰富,名花众多;珍稀,濒危植物多;植物区系成分复杂,起源古老,特有植物多;垂直分布明显,四季花卉不断;形态各异,色彩绚丽等特点,是开展赏花旅游的理想地方,笔者设计3条赏花旅游线中;（1）百花岭景区;（2）大蒿坪景区;（3）大塘大树杜鹃景区。为高黎贡山开展赏花旅游提供思路。     

Characterization of the Hydrolytic Activity of Avocado Cellulase

The cellulase produced by ripening avocado fruits (Persea americanaMill cv. Fuerte) was isolated and purified using chromatofocusing(pH 7–4) and gel filtration on a Bio- Gel P-100 column.Characteristics of the cellulase were assessed by using, assubstrates, a range of polysaccharides containing various sugarresidues and varying types of linkages between the residues.Only those substrates containing (14)-ß-glucosyl linkageswere hydrolyzed by the purified enzyme. Two polysaccharidesthat were extensively hydrolyzed by the cellulase were carboxymethylcelluloseand (13),(14)-ß-D-glucans such as from Avena endospermcell walls. Characterization of the activity in the degradationof the mixed linked glucan of Avena and cellodextrins indicatedthat the enzyme has a limit recognition-hydrolytic site of four(l4)-ß linked glucose residues. It was also foundthat the enzyme could cleave only (14)-ß-linkagesthat were adjacent to other (l4)-ß-D-glucosyl linkages.Activity of the cellulase against isolated avocado fruit cellwalls indicated that the purified enzyme was incapable of appreciablysolubilizing the cellulosic components of these walls. ¹Supported in part by National Science Foundation Research GrantPCM 7818588. ²USDA-ARS, Dairy Forage Research Center, University of Wisconsin,Madison, WI 53706. ³Department of Vegetable Crops, University of California, Davis,CA 95616. (Received September 14, 1985; Accepted February 12, 1986)     

GA_1和GA_3在樱桃幼果及枝条中的代谢

ＧＡ_１和ＧＡ_３在樱桃幼果及枝条中的代谢马焕普（中国农业科学院果树研究所,兴城１２５１００）ＢｌａｋｅＰＳＢｒｏｗｎｉｎｇＧ（国际园艺研究中心,东茂林,英国）关键词：樱桃,赤霉素,代谢最近,Ｂｌａｋｅ等（１９９３）从樱桃（Ｗ。ｕｓａｕｎ）幼果中分离出...