-(Desiccation tolerance and storage of seeds of Caesalpinia echinata Lam. (Brazil Wood), a species from the Atlantic Forest). The exploitation of Caesalpinia echinata reduced markedly the original geographic distribution of the species. The knowledge of seed physiology, mainly desiccation tolerance and storability, could be helpful for the conservation of the species and future recovery of degraded areas of the Atlantic Forest. Desiccation study was performed in four categories of seeds selected according to colour and size (I, II, III, and IV stages), being submitted to drying at 40 ºC and 50 ºC until 8% water content was reached. Freshly harvested and dried (9.7%) seeds were stored in cold chamber (7 ± 1 ºC) or in natural environment (22 ± 7 ºC) using packages with three different levels of permeability. Results showed that seeds of C. echinata are tolerant to desiccation (until 7.6% wet basis) and seed sensitivity to drying is dependent on the initial quality of the seed. Seeds stored in natural environment lost their viability in three months while under low temperatures germination was 80% after 18 months.RESUMO -(Tolerância à dessecação e armazenamento de sementes de Caesalpinia echinata Lam. (pau-brasil), espécie da Mata Atlântica). A exploração descontrolada do pau-brasil reduziu sua distribuição original a pequenos remanescentes na atualidade. O conhecimento da fisiologia da unidade de dispersão da espécie pode contribuir para a ampliação de seu cultivo, uso racional e conservação. A sensibilidade das sementes à dessecação foi avaliada em sementes recém-colhidas, separadas em quatro categorias (estádios I, II, III e IV), segundo avaliação visual de tamanho e cor. Sementes de cada estádio foram submetidas a secagem a 40 °C e a 50 °C, até que o teor de água atingisse 8% (base úmida). A capacidade de manutenção da viabilidade das sementes durante o armazenamento foi avaliada em diferentes embalagens (permeável, semi-permeável e impermeável), em ambiente natural (22 ± 7 °C) ou em câmara fria (7 ± 1 °C), com sementes submetidas ou não a secagem inicial, que reduziu o teor de água para 9,7%. Os resultados permitiram concluir que as sementes de C. echinata são tolerantes à dessecação, mas a sensibilidade à secagem pode ser influenciada pela qualidade inicial das sementes. Quando armazenadas sob condições normais de ambiente podem perder a viabilidade em menos de três meses. Sob temperatura baixa foi possível manter a viabilidade das sementes por até 18 meses, com germinação superior a 80%. A espécie em estudo comporta-se como ortodoxa, tolerando dessecação até atingir 7,6% de água, o que pode facilitar o armazenamento e ampliar o potencial de conservação, para fins de reposição das populações naturais.

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The underground reserve organs of yacon (Polymnia sonchifolia Poep. Endl.), similarly to other economically important Asteraceae, accumulate more than 60%, on a DW basis, of inulin type β(2‐1) fructans, mainly oligomers (GF2–GF16). Although sucrose:sucrose 1‐fructosyl transferase (1‐SST), fructan:fructan 1‐fructosyl transferase (1‐FFT) and fructan 1‐exohydrolase (1‐FEH) were properly described and characterized from a number of plant species, detailed information about their activities in different organs during development are rather scarce in the literature. In the present work 1‐SST, 1‐FFT and 1‐FEH activities were measured monthly in rhizophores and tuberous roots of yacon plants during their complete growth cycle under field conditions. Results showed that 1‐SST activity in rhizophores was always higher than 1‐FFT activity and increased up to 8 months of cultivation, decreasing to initial values at the end of the growth period. In the tuberous roots 1‐SST activity was also higher than 1‐FFT but varied differently. The higher values were found at the beginning of tuberization (3‐month‐old plants) and at the flowering phase (7‐month‐old plants). Results also showed that synthesizing activities in yacon plants were always higher in rhizophores than in the tuberous roots, while hydrolysing activity predominated in the latter, mainly when 1‐kestose and nystose were used as substrates. 1‐FEH from yacon plants showed low efficiency when commercial inulin from Helianthus tuberosus was utilized as substrate. The analysis of the enzymatic activities performed during growth of yacon clearly indicated the most appropriate source organ and phase of development to obtain the highest enzymatic activities for purification purposes and for the production of fructo‐oligosaccharides (FOS). Furthermore, the results suggested that the relative levels of activities of 1‐SST, 1‐FFT and 1‐FEH could be involved in the chain length distribution of the fructan molecules found in rhizophores and in tuberous roots of this species.

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The underground organs of Vernonia herbacea (Vell.) Rusby, known as rhizophores, acumulate 80% of their dry mass as fructans of the inulin type. In view of the growing industrial use of fructans as dietetic and general food products, and of their medical application, the present investigation aimed at evaluating the effect of mineral fertilization and period of cultivation on the production of these carbohydrates in field trials. Plants used in the experiments were obtained by vegetative propagation from rhizophores collected from plants growing in natural areas of the cerrado, and cultivated for two years. Fertilization consisted of N:P2O5:K2O (80:200:150 kg.ha-1) plus 80 kg.ha-1 nitrogen as dressing. Soil fertilization did not stimulate biomass or inulin production, but in the second year of cultivation a dramatic gain in biomass and inulin was detected in both treated and control plants. Inulin production varied from 113 to 674 kg.ha-1 which corresponds to 43% of the rhizophore dry mass. The composition of fructans was not altered by fertilization, although treated plants had a higher proportion of sucrose and fructans with degree of polymerization 3-8 in the second year of cultivation. The results identify this species as a fructan source similar to other commercial crops and recommend further agronomic studies, aimed at increasing the production of this polysaccharide.
Rusby, denominados rizóforos, acumulam frutanos do tipo inulina como principal carboidrato de reserva, que podem atingir até 80% da massa seca em condições naturais do cerrado. Em vista do uso crescente da inulina na indústria de produtos dietéticos e alimentícios em geral e de sua aplicação médica, o presente trabalho teve por objetivo avaliar a produção desse carboidrato em condições de campo sob o efeito da adubação mineral e tempo de cultivo. As plantas utilizadas no experimento foram obtidas por multiplicação vegetativa a partir de rizóforos coletados de plantas crescendo em condições naturais e, em seguida cultivadas em área de cerrado natural por dois anos. A adubação básica consistiu de N:P2O5:K2O (80:200:150 kg.ha-1) com uma adubação nitrogenada de cobertura (N=80 kg.ha-1). Os resultados mostraram que a adubação não estimulou o aumento da biomassa e nem a produção de inulina. O tempo de cultivo, entretanto, afetou positivamente a produtividade de V. herbacea, havendo um ganho expressivo em biomassa e em frutano total (inulina), no segundo ano de cultivo. A produção de inulina variou de 113 a 674 kg.ha-1, correspondendo a 43% da matéria seca do rizóforo. A composição básica dos frutanos não foi alterada, embora as plantas adubadas tenham apresentado maior proporção de sacarose e frutanos com grau de polimerização de 3 a 8 no segundo ano de cultivo. Os resultados obtidos até o momento indicam ser esta espécie uma fonte de inulina comparável a outras culturas comerciais, sendo recomendado, portanto, a realização de estudos agronômicos, visando ao aumento da produção desse polissacarídeo

Comparative analysis of zygotic and somatic embryogenesis of Acca sellowiana showed higher amounts of sucrose, fructose, raffinose, and myo-inositol in zygotic embryos at different developmental stages than in corresponding somatic ones. These differences were mostly constant. In general, glucose levels were significantly lower than the other soluble carbohydrates analyzed, showing minor variation in each embryo stage. Despite the presence of sucrose in the culture medium, its levels conspicuously diminished in somatic embryos compared with the zygotic ones. Raffinose enhanced parallel to embryo development, regardless of its zygotic or somatic origin. Analysis of the soluble carbohydrate composition of mature zygotic cotyledon used as explant pointed out fructose, glucose, myoinositol, sucrose, and raffinose as the most important. Similar composition was also found in the corresponding somatic cotyledon. Total soluble carbohydrates varied inversely, decreasing in zygotic embryos and increasing in somatic embryos until the 24th d, at which time they increased rapidly about sixfold in zygotic embryos until the 27th d, a period coinciding with the zygotic proembryos formation. Such condition seems to reflect directly the variation of endogenous sucrose level, mainly because glucose and fructose diminished continuously during this time period. This means that, in terms of soluble sugars, zygotic embryo formation occurred under a situation represented by high sucrose amounts, simultaneously with low fructose and glucose levels, while in contrast, somatic embryo formation took place under an endogenous sugar status characterized by a substantial fructose enhancement. Starch levels increased continuously in zygotic embryos and decreased in somatic ones, the reverse to what was found in fructose variation. Starch accumulation was significantly higher in somatic torpedo and cotyledonary embryos than in the corresponding zygotic ones.