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Optimization of jenipapo in vitro seed germination process

The in vitro seed germination is an effective alternative for quickly obtaining explants with sanitary quality. However, jenipapo seeds present slow and uneven germination. Therefore, internal and external factors to seed which directly interfere in the process, they must be identified, in order to adapt better techniques to obtain seedlings. In this sense, this work aimed to optimize the in vitro germination of Genipa americana L. seeds by evaluating different factors (light quality, GA3 treatment, pre-soaking in distilled water, growing media and stratification in the dark). It was found that the seed germination of G. americana was indifferent to light, however, the best results were obtained under conditions of continuous darkness; There was no effect of the application of exogenous GA3; The pre-soaking in distilled water for 48 h contributes to obtaining better germination rates; And the reduction in MS medium salts, and laminating the pretreatment in the dark maximizes the germination potential of seeds.Therefore, the optimal conditions for in vitro germination of G. americana L. seeds requires pre-soaking in distilled water for 48 hours and inoculation into culture media consisting of 1/2 MS + 15 g L-1 sucrose, with stratification in the dark for 16 days, followed by the transfer to growth chambers with lighting provided by white fluorescent lamps.

Germinação in vitro e desenvolvimento pós-seminal de plântulas de Pilosocereus aurisetus (Werderm.) Byles & G.D. Rowley (Cactaceae)

Pilosocereus aurisetus e uma especie de cactos de importância economica e ambiental que se encontra em risco de extincao. A propagacao em areas naturais ocorre, principalmente, de forma sexuada; entretanto, nao ha registro da germinacao e viabilidade de sementes e morfologia pos-seminal de plântulas dessa especie. Assim, objetivou-se avaliar a germinacao de sementes e descrever a morfologia do desenvolvimento pos-seminal de plântulas de P. aurisetus. Para isso, sementes, armazenadas em condicoes ambientais por 19 meses, foram submetidas aos tratamentos: embebicao em agua por 24 horas; pre-resfriamento; imersao em solucao de giberelina, nas concentracoes de 250 mg L-1 e 500 mg L-1; e um tratamento controle. As sementes foram colocadas para germinar em meio de cultura MS, por 30 dias, quando se avaliou a percentagem de germinacao. O delineamento estatistico foi o inteiramente casualizado, com cinco tratamentos e quatro repeticoes, sendo dispostas 25 sementes por parcela. A caracterizacao pos-seminal foi realizada por um periodo de 60 dias, utilizando-se microscopio binocular, com base nas Regras para Analise de Sementes. Maior percentagem da germinacao de sementes ocorreu no controle, ou quando embebidas por 24 horas, sendo observados 90% e 83%, respectivamente. A morfologia do desenvolvimento pos-seminal indicou que a germinacao e do tipo epigea, com hipocotilo de reserva; suas plântulas sofrem modificacoes na regiao do colo, para a emissao de raizes, e apresentam cerdas no apice caulinar, mesmo na fase inicial da expansao cotiledonar. A diferenciacao e inicio da formacao das costelas iniciam-se aos 60 dias apos a germinacao, com o desenvolvimento do epicotilo.

In vitro propagation of Campomanesia rufa: An endangered fruit species

The Campomanesia rufa is a fruitful species native from Brazil considered as endangered by the IUC (International Union for Conservation of Nature) and low information regarding its propagation is available. In this context, the aim of the present study was to develop in vitro germination, micropropagation and callogenesis protocols for the species. For in vitro germination, seeds were inoculated in MS medium supplemented with GA3 (gibberellic acid) and for shoot induction, the medium was supplemented with three different cytokinins BA (benzyladenine), BAP (6-Benzylaminopurine) or TDZ (Thidiazuron). For shoot growth, culture medium containing BA, BAP, TDZ were maintained under white fluorescent lamps and blue:red light-emitting diodes (LED). GA3 was also tested on in vitro shoot elongation. For oxidation control, the medium was supplemented with PVP (polyvinylpyrrolidone) and for callus induction, 2.4-D (dichlorophenoxyacetic acid). The results showed 68% germination regardless of GA3 concentration. In the propagation stage, BAP at 4.5 μM induced a higher number of shoots (4.53) and LED lamps as the light source combined with the culture medium with 1 μM BAP induced a higher number of shoots (4.08). The highest average of C. rufa length (31.9 mm) was obtained using 8.8 μM GA3. The use of PVP (584.3 uM) controls up to 27.3% oxidation in young leaf explants. The use of 10 μM 2.4-D leads to a higher callus formation (58.7 %). Therefore, it can be concluded that the use of BAP is efficient in the induction of shoots, PVP controls oxidation leaf segments, and 2.4-D induces callus in C. rufa.

Fotorrespiração e metabolismo antioxidante em plantas jovens de seringueira cultivadas sob diferentes fontes de nitrogênio (NO3 - eNH4 +)

In this study, the effects of nitrate (NO 3 - ), ammonium (NH 4 + ) and of the absence of nitrogen (N) in photosynthesis, photorespiration and antioxidant m...