Abstract This study evaluate growth, gas exchange, solute accumulation and activity of antioxidant enzymes in dwarf cashew clones subjected to salinity. Shoot dry mass reduced 26.8% (CCP06) and 41.2% (BRS189) at 16 dS m-1, concerning control. For net photosynthesis, CCP06 and BRS189 presented 69.8% and 34.7% of reduction, respectively. Na+ and Cl- contents increased in leaves and roots, in both clones, although CCP06 leaves presented Na+ concentrations lower than those of BRS189, the first one was the clone that the most accumulated such toxic ion, whereas K+ content remained almost unchanged for both clones. Soluble N-amino was the organic solute that more varied with salinity in cashew seedlings. Salt stress increased the activity of superoxide dismutase in both clones, mainly 16 dS m-1 treatment. Additionally, salinity promoted increases in ascorbate and guaiacol peroxidase activities, and the last enzyme was the main involved in H2O2 removal. Despite the reductions in growth and gas exchange, dwarf cashew seedlings of both clones presented an osmotic adjustment mechanism, and an efficient enzymatic antioxidant system that were able to attenuate the salt and oxidative stress, respectively. Our research suggested that BRS189 clone is more tolerant to salt stress than CCP06.

ABSTRACT The preservation of banana genetic material is usually performed through seedlings. However, most banana cultivars do not produce seed and are propagated vegetatively. Therefore, cryopreservation is a feasible technique that allows the preservation of banana genotypes indefinitely. For the success of cryopreservation protocols, the selection of cryoprotectants and pre-freezing techniques are important factor. Therefore, the objective of this study was to verify the effects of different cryoprotectants with and without 1% phloroglucinol and pre-cooling periods on the development of a protocol for cryopreservation of in vitro rhizomes ofMusa accuminata(AAA) cv Grand Naine banana. The addition of 1% phloroglucinol to the cryoprotective solutions, such as PVS2 enhanced recovery of cryopreserved banana rhizomes. In addition, pre-cooling of explants in ice for 3 hours in PVS2 + 1% of phloroglucinol allowed efficient cryopreservation of banana rhizomes, followed by successful recovery and regeneration of in vitro shoots of banana cv Grand Naine.

O objetivo do trabalho foi verificar possíveis efeitos alelopáticos exercidos por extratos aquosos de folhas de cumaru (Amburana cearensis) e malva-santa (Plectranthus barbatus) sobre a germinação de sementes de caruru (Amaranthus deflexus). As sementes de caruru foram colocadas para germinar em placas de petri em contato com extratos vegetais aquosos obtidos a partir de folhas de cumaru e malva-santa sob dois métodos de preparação - extrato aquoso das folhas frescas e extrato aquoso por infusão das folhas secas - e duas dosagens - 50 e 100 g L-1. Foi utilizado o delineamento inteiramente casualizado com 4 repetições e uma testemunha isolada compondo um fatorial 2 x 2 x 2 + 1. Foi determinada a porcentagem final e o índice de velocidade de germinação. A análise dos dados revelou diferença entre os tratamentos e a testemunha, condicionando graus diferentes de alelopatia para os extratos usados afetando drasticamente a germinação do caruru. O extrato a base de folhas frescas de cumaru apresenta alto nível de alelopatia de modo a impedir quase que completamente a germinação do caruru. A dose, com efeito, mais prejudicial para a germinação do caruru foi a de 100 g L-1.

The objective was to verify possible allelopathic effects exerted by aqueous extracts of leaves of Amburana cearensis and Plectranthus barbatus on the seed germination of the weed Amaranthus deflexus.A. deflexus seeds were put to germinate in Petri plates containing aqueous plant extracts obtained from A. cearensis and P. barbatus leaves under two tillage methods - aqueous extract from fresh leaves and aqueous extract by infusion of dried leaves - and two dosages - 50 and 100 g L-1. We used a completely randomized design with 4 replications and a detached witness composing a factorial 2 x 2 x 2 + 1. It was determined the final percentage and germination speed index. Data analysis revealed differences between treatments and the witness, conditioning different allelopathy levels for the extracts used, dramatically affecting the germination of A. deflexus. The A. cearensis fresh leaves extracts has a high level of allelopathy since they prevent almost completely the germination of the weed A. deflexus. The most damaging dosage for germination of A. deflexus was 100 g L-1.

Cereus jamacaru, uma cactácea encontrada comumente no nordeste brasileiro, é amplamente usada como planta forrageira e como ornamental e medicinal. No entanto, existem poucas informações sobre os aspectos fisiológicos e bioquímicos relacionados à sua germinação. O objetivo desse estudo foi avaliar a mobilização de reservas durante a germinação e o crescimento inicial de plântulas de C. jamacaru. Para isso, as sementes foram germinadas em câmaras de germinação e coletadas aos 0, 2, 4, 5, 6, 8 e 12 dias após a germinação para as análises fisiológicas e bioquímicas. As sementes quiescentes apresentaram tegumento espesso e rugoso e embriões curvados. Os lipídios foram as reservas mais abundantes, correspondendo aproximadamente a 55% e 65% da massa seca dos cotilédones e eixo hipocótilo-radícula, respectivamente. Os açúcares solúveis e o amido foram as reservas menos abundantes, correspondendo aproximadamente a 2,2% da massa seca dos cotilédones, embora suas reservas tenham apresentado mudanças significativas durante a germinação. As proteínas solúveis corresponderam a 40% da massa seca dos cotilédones, que foi reduzida a 81% no período final de germinação comparado a sementes quiescentes. As sementes de C. jamacaru podem ser consideradas oleaginosas devido ao seu alto conteúdo de lipídios. Além disso, os lipídios foram as principais reservas mobilizadas durante a germinação porque seus níveis foram fortemente reduzidos durante esse período, enquanto que as proteínas foram a segunda reserva mais utilizada nesse processo.

Cereus jamacaru, a Cactaceae found throughout northeast Brazil, is widely used as cattle food and as an ornamental and medicinal plant. However, there has been little information about the physiological and biochemical aspects involved in its germination. The aim of this study was to investigate its reserve mobilization during germination and early seedling growth. For this, C. jamacaru seeds were germinated in a growth chamber and collected at 0, 2, 4, 5, 6, 8 and 12 days after imbibition for morphological and biochemical analyses. Dry seeds had wrinkled seed coats and large, curved embryos. Lipids were the most abundant reserve, comprising approximately 55% and 65% of the dry mass for cotyledons and the hypocotylradicle axis, respectively. Soluble sugars and starch were the minor reserves, corresponding to approximately 2.2% of the cotyledons' dry mass, although their levels showed significant changes during germination. Soluble proteins corresponded to 40% of the cotyledons' dry mass, which was reduced by 81% at the final period of germination compared to dry seeds. C. jamacaru seed can be classified as an oil seed due to its high lipid content. Moreover, lipids were the main reserve mobilized during germination because their levels were strongly reduced after seed germination, while proteins were the second most utilized reserve in this process.