A B S T R A C TThe knowledge concerning the physiology of germination in saline areas may contribute to the development of more efficient cultural practices and adequate choice of planting areas. Thus, the objective of this study was to evaluate the effects of saline and temperature stress on germination and vigor of Piptadenia moniliformis (a species known in Brazil as "catanduva") seeds. The treatments were distributed according to a completely randomized design in accordance with a 3 x 6 factorial arrangement (temperature x osmotic potential), with four replicates of 25 seeds each. The seeds were put to germinate at constant temperatures of 25, 30, and 35 °C on paper towel moistened in distilled water (0.0) and NaCl solutions at 0.2, 0.4, 0.6, 0.8 and 1.0 MPa. The results were evaluated in terms of germination percentage and germination speed index, seedling (root and shoot) length, and total dry matter. P. moniliformis seeds were able to germinate under temperatures of 25 and 30 °C and tolerate osmotic potentials of up to -0.6 MPa; from this point on, there is progressive decrease in the physiological quality of seedlings.Estresse salino e temperaturas na germinação e vigor de sementes de Piptadenia moniliformis Benth R E S U M O O conhecimento da fisiologia da germinação em locais salinos pode contribuir para o desenvolvimento do manejo e da escolha adequada das áreas de plantio. Com isto objetivou-se avaliar o efeito do estresse salino e temperaturas na germinação e vigor de sementes de catanduva (Piptadenia moniliformis Benth.). O delineamento experimental foi o inteiramente casualizado, com os tratamentos distribuídos em esquema fatorial 3 x 6 (temperatura x potencial osmótico) em quatro repetições de 25 sementes. Para tal, as sementes foram colocadas para germinar nas temperaturas constantes de 25, 30 e 35 °C e semeadas em substrato de papel toalha umedecido com água destilada (0,0) e soluções de NaCl a -0,2; -0,4; -0,6; -0,8 e -1,0 Mpa; as variáveis analisadas foram a porcentagem e o índice de velocidade de germinação, comprimento de plântulas (raiz e parte aérea) e massa seca total; as sementes de P. moniliformis germinadas sob temperaturas de 25 e 30 °C suportam concentrações salinas com potencial osmótico de até -0,6 MPa sendo que a partir de então ocorre diminuição progressiva da qualidade fisiológica das plântulas.

ABSTRACT. The invasion by Cryptostegia madagascariensis causes economic and environmental problems in Northeastern Brazil. Current study evaluates the initial growth of C. madagascariensis on light gradient. The experiment used 0, 30, 50 and 70% shading treatments arranged in a completely randomized design and evaluated in four periods, namely, 35, 50, 65 and 80 days. Height, absolute growth rate, relative growth rate, number of side branches, number of leaves, leaf area, specific leaf area, leaf area ratio, root mass ratio, stem mass ratio, leaf mass ratio and leaf area/root mass ratio were evaluated. Results showed that the height was greater in shade environments, and the greater the available light, the greater was the number of side branches. C. madagascariensis is able to change the leaf area, specific leaf area and biomass allocation in different shadings. Since C. madagascariensis varies growth forms and performs morphological adjustments to increase light uptake, the plant has warranted success during the initial growth under different shadings.Keywords: functional traits, Caatinga, shading, morphological adjustments, biomass. Influência da luz no crescimento inicial da invasora Cryptostegia madagascariensis Bojer no semiárido Brasileiro RESUMO.A invasão da Cryptostegia madagascariensis causa problemas econômicos e ambientais no Nordeste do Brasil. O objetivo do trabalho foi estudar o crescimento inicial da C. madagascariensis em gradiente de luz. O experimento utilizou os tratamentos de 0, 30, 50 e 70% de sombreamento, dispostos em um delineamento experimental inteiramente casualizado e avaliados em quatro períodos: 35, 50, 65 e 80 dias. Foram avaliados a altura, a taxa de crescimento absoluto, a taxa de crescimento relativo, o número de ramos laterais e de folhas, a área foliar, a área foliar específica, a razão de área foliar, a razão de massa da raiz, a razão de massa do caule, a razão de massa das folhas e a razão área foliar/massa da raiz. Os resultados mostraram que a altura foi maior em ambientes sombreados e, quanto mais luz disponível, maior o número de ramos laterais. A C. madagascariensis é capaz de alterar a área foliar, a área foliar específica e na alocação de biomassa nos diferentes sombreamentos. Portanto, a C. madagascariensis varia a forma de crescimento e realiza ajustes morfológicos para aumentar a captação de luz, o que garantiu seu sucesso durante o crescimento inicial em diferentes sombreamentos.

Tolerance to water and salt stress during germination and growth of agricultural species might have superior results when seeds are submitted to priming processes. The objective of the present study was to evaluate the use of hydropriming and hormonal priming with gibberellic acid (GA 3 ) on the tolerance of divergent genotypes of sorghum to salt and water stress during germination and seedling growth. The genotypes analyzed were cultivar BRS 330 and lineage 201420, which are the most and least tolerant to water and salt stress, respectively. Sowing was undertaken under control (no stress), water stress (−0.6 MPa), and salt stress (20 dS·m −1 ) conditions, and the seeds were subjected to the following treatments: control-no immersion; hydropriming-immersion for 2 hours in distilled water; and hormonal priming-immersion in GA 3 solutions, at concentrations of 50, 75, and 100 ppm, for 2 hours. After soaking, the seeds were dried for 24 hours at a temperature of 30˚C ± 2˚C. The variables analyzed were percentage and germination speed index, root and shoot lengths, and root/shoot ratio. The stress conditions analyzed negatively affected the two genotypes; however, the seeds that underwent priming processes improved the performance of the genotypes under salt and water stress conditions, especially when using seeds of the more tolerant genotype (BRS 330) subjected to hormonal priming at 100 ppm GA 3 concentration.

The current study aimed to investigate the effects of the temperature, light, and water stress on Piptadenia stipulacea seed germination. It assessed germination percentage, speed and average germination time, root and stem length as well as the dry weight of seedlings subjected to the constant temperatures of 20˚C, 25˚C and 30˚C and alternating temperatures from 20˚C to 30˚C. A 12-hour photoperiod was established in addition to the following light conditions: white, darkness, red and far red. The experimental design was completely randomized and four replicates of 25 seeds were performed for each treatment. Regarding water stress, seeds were subjected to osmotic potentials of 0, −0.2, −0.4, −0.6, −0.8, −1.0, and −1.2 MPa, at 30˚C and 12 h light/12 h darkness photoperiods. After they were mixed, 100 seeds were randomly selected for biometric measurement and they were found to be uneven with respect to size and weight. P. stipulacea seeds germinated under all tested temperature and light conditions. Germination under water stress occurred up to −0.8 MPa. The conclusion is that there was no germination from −1.0 MPa. The seeds are light-indifferent and germinate at the constant temperatures of 20˚C, 25˚C and 30˚C and alternating temperatures from 20˚C to 30˚C.

RESUMOA propagação de Acnistus arborescens (fruto-do-sabiá) usualmente é feita através de estacas, devido a baixa taxa de germinação de suas sementes. O objetivo deste trabalho foi estudar o efeito da temperatura e do estimulante nitrato de potássio (KNO 3 ) na germinação do fruto-do-sabiá. O experimento foi realizado utilizando quatro regimes de temperatura (20, 25, 30 e 20-30 °C), com e sem nitrato de potássio, em delineamento inteiramente casualizado com quatro repetições de 50 sementes cada. Foram avaliados a porcentagem, o índice de velocidade e o tempo médio de germinação. Nas temperaturas constantes, o KNO 3 favoreceu a germinação, sendo as maiores porcentagens (>68%) obtidas nas temperaturas de 20 °C e 25 °C. A temperatura alternada de 20-30 °C aumentou a porcentagem de germinação, sem a adição de KNO 3, portanto além da propagação vegetativa. A produção de mudas a partir de sementes é viável.Palavras-chave: nitrato de potássio, dormência, fruto-do-sabiá, sementes. Effect of Temperature and KNO 3 in the Germination of Acnistus arborescens (Solanaceae) ABSTRACTThe propagation of Acnistus arborescens (fruto-do-sabiá) is usually made using cuttings, because the germination percentage of this species is low. The objective of this work was to study the effect of temperature and potassium nitrate (KNO 3 ) stimulant on the germination of fruto-do-sabiá. The experiment was conducted under four temperature regimes (20, 25, 30 and 20-30 °C), with and without potassium nitrate, in a completely randomized design with four replications of 50 seeds each. The percentage, speed index, and average time of germination were evaluated. Under constant temperatures, KNO 3 improved germination, with the highest percentages (>68%) obtained at the temperatures of 20 and 25 °C. The alternating temperature of 20-30 °C was effective in overcoming seed dormancy without addition of KNO 3 ; therefore, besides the vegetative propagation, the production of seedlings from seeds is viable.

RESUMO:O fruto-do-sabiá (Acnistus arborescens L). é uma espécie de uso medicinal e importância fl orestal, com poucas informações acerca dos aspectos morfológicos de frutos, sementes e plântulas. O objetivo deste trabalho foi conhecer as características morfométricas de frutos e sementes, e a morfologia da germinação de A. arborescens. Os frutos foram coletados em Guaramiranga-CE, de 20 matrizes selecionadas aleatoriamente. Os aspectos biométricos foram avaliados em uma amostra de 50 frutos e 100 sementes, e o desenvolvimento pós-seminal foi descrito baseado em observações feitas em casa de vegetação durante 40 dias. O fruto é indeiscente, carnoso, globoso e polispérmico, com peso médio de 0,53 g e com uma média de 46 sementes por fruto. As sementes possuem coloração amarelada, formato elipsoidal, sendo o embrião curvo e o endosperma esbranquiçado. As sementes apresentaram as seguintes medidas: 1,59 mm de comprimento, 1,33 mm de largura e 0,36 mm de espessura. Para a germinação, foi observado que a emissão da radícula ocorre seis dias após a semeadura e, com 35 dias, a plântula apresenta todas as estruturas iniciais. Observou-se que o fruto é globoso e polispérmico, as sementes são elipsoides, com embrião curvo, e a germinação é do tipo fanerocotiledonar, epígea e com cotilédones foliáceos. ABSTRACT: Acnistus arborescens L. is a plant species of medicinal use. Although it is important for forestry, little is known about the morphology of its fruits, seeds and seedlings. The objective of the present study was to investigate the morphometric characteristics of fruits and seeds and the morphology and germination of Acnistus arborescens L.. The fruits were collected from 20 randomly selected matrices in the municipality of Guaramiranga

A study was conducted to examine the effects of different temperatures and water stress on Encholirium spectabile seeds. We evaluated the germination percentage, speed and time of germination of small (<2.97 mm), medium (2.97 ≤ M ≤ 4.01 mm) and large seeds (>4.01 mm), at temperatures of 15˚C, 20˚C, 25˚C, 30˚C, 35˚C, 40˚C and 45˚C and a photoperiod of 12 hours of light. Seeds were subjected to osmotic potentials of 0, −0.2, −0.4, −0.6, −0.8, −1.0, −1.2 and −1.4 MPa, induced by solutions of polyethylene glycol. The results indicated an excellent germination of medium and large seeds at the temperatures of 20˚C, 25˚C, 30˚C and 35˚C. The temperature of 35˚C provided the best mean germination time of large seeds and a higher speed rate of medium and large seeds. E. spectabile seeds germinate in a wide range of water deficit of −0.2 to −1.2 MPa. Germination reduced at concentrations of −1.0 and −1.2 MPa. No germination occurred at −1.4 MPa. Larger seeds showed the higher germination potential than medium and small seeds at the temperatures of 25˚C, 30˚C and 35˚C and in the range of water deficit of −0.2 to −1.2 Mpa.

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