Ensaio recebido em 13 de novembro de 2016, versão final aceita em 23 de maio de 2017. RESUMO:Nesse trabalho propõe-se contribuir com as discussões sobre a exploração sustentável da Caatinga através de uma atualização bibliográfica sobre o tema, destacando a importância desse bioma, suas potencialidades e a necessidade de sua preservação e conservação. Foram abordadas a importância socioeconômica do bioma, as estratégias de subsistência e geração de renda (como o extrativismo e bioprodutos de valor econômico), as políticas públicas e ameaças, além de avaliar o seu uso sustentável. Com base no exposto, compreende-se que o manejo sustentável é uma possibilidade real, tecnicamente comprovada. Faz-se necessário um intenso processo de conscientização e capacitação de todos os atores envolvidos por meio da formulação de políticas públicas, que priorizem a realidade ambiental e socioeconômica do bioma, da geração, sistematização e disseminação de informações, da construção de uma matriz de incentivos adaptados à realidade local e do fortalecimento institucional, como forma de garantir a sobrevivência do ecossistema.Palavras-chave: bioma brasileiro; extrativismo sustentável; semiárido.ABSTRACT: This paper aims to contribute with the discussions about the sustainable exploitation of Caatinga through an updated review of such topic. The research highlights the importance of this biome, thus, proposing its potential, and also the need for its preservation and conservation. This study, more specifically, exposes the socio-economic importance of the biome, on subsistence and income generation strategies, discussing the extraction and bio-products of economic value, public policies and threats, and evaluation of its sustainable use. Thus, considering this discussion it is understood that sustainable management is a real possibility and technically proven. It is necessary an intense process of awareness and training of all involved actors through

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Castor (Ricinus communis), cotton (Gossypium hirsutum), and safflower (Carthamus tinctorius) are industrial crops frequently considered to be raised under high salinity of the soil or irrigation water. Sodium is the most common ion causing salinity, but other ions can also be found in toxic level. This experiment had the objective to evaluate if the presence of calcium and magnesium in the irrigation water alleviates the toxic effect of sodium in the emergence and initial growth of these three oilseed crops. Seeds were sown in trays for evaluation of emergence and in pots for evaluation of plant growth. The treatments consisted of simulations of the Na + :Ca 2+ :Mg 2+ molar ratio found in the irrigation water of the Trans-Pecos region of the States of New Mexico and Texas, USA. The saline solutions were equivalent to 0, 50, 100, 150, 200, and 250% of the salt composition found in the reference water. Some solutions contained the three salts, while others contained only Na + , and the electrical conductivity varied from 0.7 to 13.7 dS m −1 among treatments. For the analysis of plant growth, the treatments were imposed after seedling emergence, and the plants were harvested after 30 days. In castor and safflower, the salinity effect was associated with the electrical conductivity rather than with the salt composition. The cotton genotype had been previously selected to be tolerant to Na + , but it was sensitive to Ca 2+ and Mg 2+. Safflower plants did not survive 30 days under exposure to salinity higher than 9.6 dS m −1 with any salt composition. In conclusion, Ca +2 and Mg +2 did not alleviate the toxic effect of Na + , and the mechanisms of salt tolerance in cotton were ion-specific.

RESUMOTradicionalmente, a propagação do pinhão-manso (Jatropha curcas) é realizada através de sementes; e em muitas situações a propagação vegetativa é uma importante alternativa para a propagação desta espécie. Objetivou-se, com este trabalho, avaliar como o comprimento e a parte do ramo de onde se extraem as estacas influenciam a capacidade de enraizamento adventício e de crescimento de mudas de pinhão-manso. Os tratamentos foram arranjados em esquema fatorial 3 x 4, sendo os fatores três posições da estaca no ramo (apical, mediana e basal) e quatro comprimentos de estaca (10, 15, 20 e 25 cm). Adotou-se o delineamento inteiramente casualizado com quatro repetições e dez estacas por parcela. Aos 70 dias após o estaqueamento foi avaliado o número de brotações e de ramos formados, o comprimento dos ramos, número de folhas, área foliar, número de raízes, massa seca de brotações e massa seca de raízes, cujos resultados indicaram que a posição do ramo em que se extrai a estaca de pinhão-manso (base, meio ou ápice) não influencia o crescimento inicial ou a formação das mudas; no entanto, o comprimento da estaca modifica o crescimento inicial das mudas sendo que o maior crescimento é obtido com estacas em torno de 22 cm. Palavras-chave: Jatropha curcas, estaquia, propagação vegetativaLength of cuttings and the part of the branch section for production of Jatropha seedlings ABSTRACT Jatropha curcas is traditionally propagated by seed. However, in several situations the vegetative propagation is an important alternative and its technology needs to be developed. The objective of this study was to evaluate how the length and the portion of the branch from where the cuttings are extracted, influence the rooting and growth capacity of Jatropha cuttings. The treatments were arranged in a 3 x 4 factorial design, with three cutting positions (apical, middle and basal) and four cutting lengths (10, 15, 20, and 25 cm). A completely randomized design with four replications and ten cuttings per plot was adopted. At 70 days after planting, the cuttings were evaluated for the number of sprouts and branches, branch length, number of leaves, leaf area, number of roots, and dry mass of shoots and roots. The position from where the cuttings are extracted (apical, middle or basal) did not influence its capacity for rooting and the growth of the seedlings. The cutting length influences the initial growth, and the best growth was obtained in cuttings of around 22 cm.

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