Báo cáo lâm nghiệp: Germination and storage of recalcitrant seeds of tropical forest tree specie

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Germination and storage of recalcitrant seeds of tropical forest tree species...
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Báo cáo lâm nghiệp: "Germination and storage of recalcitrant seeds of tropical forest tree specie"Germination and storage of recalcitrant seeds of sometropical forest tree speciesF. Corbineau D .CômeLaboratoire de Physiologie des Organes V6g6taux apr6s Recolte, CNRS, Meudon, and UniversitéPierre-et-Marie-Curie (Paris VI), Paris, France Materials and MethodsIntroduction Experiments were carried out with seeds of twoSeeds have been termed orthodox or Dipterocarps collected in Thailand at the Phurecalcitrant by Roberts (1973) to describe Khac Botanical Garden (Shorea roxburghii) andtheir storage behavior. Orthodox seeds the Meak Lek Arboretum (Hopea odorata), andtolerate dehydration down to 5-10% (dry seeds of Simarouba amara (Simaroubaceae)weight basis) without damage. Prepared and Symphonia globulifera (Guttiferae) collected in the dense forest near Kourou, French Guiana.in this manner, these seeds can be stored Germination tests were performed in dark-for long periods and their viability can be ness, at temperatures between 5 and 35°C, onprolonged at the lowest temperature and cotton wool saturated with deionized water andmoisture content possible. Recalcitrant placed in plastic rectangular boxes (18 cm longseeds are highly hydrated and they cannot x 12 cm wide x 5.5 cm deep). 50-100 seeds were used in each test (10-25 seeds per box).withstand intensive desiccation. They To study the effect of dehydration on viability,originate predominantly from tropical or seeds were placed in open air at 20°C and 55%subtropical tree species. These seeds can relative air humidity. Samples were periodicallyonly be stored in wet medium to avoid removed, weighed and placed for germinationdesiccation injury and at relatively warm at 30°C. Viability was expressed by the maxi- mal germination percentage. Mois content ..;a htemperature, since most of them are sen- calculated fresh weight basis. was on asitive to chilling (King and Roberts, 1979). Wet storage was performed at 5, 8, 10, 12, The aim of the present study was to 15 and 20°C, on cotton wool imbibed with deio- nized water after seed treatment with quinolate the germination of some recalci-analyze (copper oxyquinoleate). Viability was periodical-trant seeds of tropical forest trees, and the ly tested by transferring seeds to 30°C.effects of dry and wet storage on their via- All results seeds visually healthy at concernbility. harvest time.* New address: Laboratoire de Physiologie V6g6tale AprJliquée. 4, pl. Jussieu. Tour 53, 75230 Paris Cedex 05, ussieu, pphqu£e,France.ResultsGermination of freshly harvested seedsFreshly harvested seeds had dorman- nocy. In all cases, germination best at wasrelatively high temperatures (optimum at25-30°C) (Fig. 1Below 15°C, it wasreduced (Shorea roxburghii) or impossible(Symphonia globulifera and Simaroubaamara), but h’opea odorata seeds germi-nated at 5°C. evenEffect of dry storageInitially, the moisture content of meanseeds relatively high: 67% for Sym- wasphonia globulifera, 39% for Simaroubaamara, 33% for Hopea odorata and 26%for Shorea roxt All seeds were urg/7/7. ’dead when their mean moisture contentsdecreased to about 8% for Simaroubaamara, 15% for Shorea roxburghii andI i - 1 11 IHopea odorata and 26% for Symphoniaglobulifera (Fig. 2). Simarouba seedsremained viable at relatively low moisturecontent, but they produced abnormalseedlings.Effects of wet storageSeeds often started to germinate duringstorage. Moreover, seeds or seedlingswere easily injured by chilling when thetemperature decreased below 10°C forShorea roxburghii, 15°C for Symphoniaglobulifera and 20°C for Hopea odorataand Simarouba amara (Fig. 3). Attemperatures that do not result in chillinginjury, seedling growth was too fast toallow extended storage. Storage durationdid not exceed 2-3 mo ...