Marilene Leão Alves Bovi

Tolerância à dessecação de sementes de palmito-vermelho (Euterpe espiritosantensis Fernandes)

With the objective of identifying the desiccation tolerance of Euterpe espiritosantensis seeds, two lots of fruits were picked in the collection of palm trees of the Agronomic Institute of Campinas (Ubatuba, State of Sao Paulo) and transported in impermeable packing to Faculdade de Ciencias Agronomicas/UNESP Botucatu (State of Sao Paulo), where they were shelled. The seeds were submitted to drying in silica gel, starting from the non-dehydrated control (51.4% and 46.6% of initial water content), taking samples at each 12 or 24 hours. The effects of dehydration were evaluated by means of germination test, percentage and speed of embryo protrusion, botton, plumule, and seedlings length. Seed dry matter and water content were also evaluated. It was concluded that the seeds of E. espiritosantensis are recalcitrant, presenting higher initial percentage of germination (90.0% to 87.5%) when not dehydrated (51.4% to 46.6% of water content). Water contents lower than 40.7%-51.4% reduced the vigour and germination rates. All seeds died when the water contents were lower than 13.4%-15.8%.

Fotossíntese, condutância estomática e transpiração em pupunheira sob deficiência hídrica

Research results on physiological aspects of peach palm (Bactris gasipaes Kunth), a native fruit tree from tropical America, are scarce. Trying to fill this gap, a water deficit experiment was performed under nursery conditions during 13 days, utilizing 12 months old plants. The main objective was to evaluate peach palm responses to water deficit. The measured variables were: CO2 assimilation rate, transpiration rate, stomatal conductance and leaf water potential. Data were collected daily in a laboratory, under a photosynthetic photon flux (PPF) of 1200 mm-2 s-1, and studied by variance and regression analysis. Significant decreases of leaf water potential values and gas exchange rates were verified when water was withhold for more than six days. The smallest values were found at the tenth day without water replacement, with a reduction of 92% of the net photosynthetic rate, 87% of the stomatal conductance and 70% of the transpiration. By that time, the smallest measured leaf water potential was ¾1.9 MPa. Recovering from water stress was accomplished two days after rewatering, except for stomatal conductance. The partial closing of the stomata (decrease in stomatal conductance) and the reduction of photosynthesis, suggest the existence of an acclimation mechanism of the peach palm, diminishing water loss under moderate stress.

Desidratação de sementes de quatro lotes de pupunheira: efeitos sobre a germinação e o vigor

The dessication tolerance of four seed lots of spineless pejibaye (Bactris gasipaes Kunth) harvested at Yurimaguas (Peru); Camamu and Pirai do Norte (Bahia State, Brazil) and Pindorama (Sao Paulo State, Brazil) was identified. The seeds were dried in a drying chamber starting with undried controls. Samples were drawn every 24 hours. Dessication effects were evaluated by means of germination test (until 184 days, vermiculite, 20-30oC), germination first counting (36 days), germination speed and seed water content. It was verified that seeds from that species are susceptible to dehydration, with higher initial germination percentage (59 to 84%) when undried (47 to 38% of water content). Water contents lower than 28 to 23% reduced significantly seed germination and vigor. All seeds died when the seed water content was lower than 15% (seed lots 2 and 4) and 13% (seed lots 1 and 3).

Understanding the threats to biological diversity in southeastern Brazil

Habitat destruction and the over-exploitation of species are perhaps thetwo most important processes threatening biodiversity. Whilst the growing humanpopulation puts considerable pressure on biological resources, a number ofsocial and economic factors tend to augment over-exploitation of theseresources. Here we show that the over-exploitation of the tropical palm treeEuterpe edulis Mart., as a consequence of social problems,has contributed significantly to its extinction in several forest fragments andalso to the disappearance of many wild animal species which used to be found inareas of the Atlantic Rain Forest (Brazil). Some of these species have been lostas a direct result of people hunting the animals when they went harvestingE. edulis while others disappeared as a consequence of thedecrease in food availability or by alterations in the trophic structure.

Desiccation effects on germination and vigor of King palm seeds

The desiccation tolerance of Archontophoenix alexandrae (Wendl. & Drude) seeds was determined and the most sensitive vigor test for assessing seed deterioration of this species was identified. Mature fruits were harvested in the palm collection of the Instituto Agronomico in Campinas, Brazil. Depulped fruits were transported in impermeable packages to the Faculdade de Agronomia in Botucatu, where the seeds were dried. As the seed moisture decreased, germination, seedling length, electrical conductivity and moisture were measured. The seeds of A. alexandrae are recalcitrant, with high germination percentage (over 67%) when undried (47% seed moisture). Lowering seed moisture below 31.5% reduced the germination rate significantly (<52.5%). Total germination failure was observed when seed moisture reached 15.1%. The electrical conductivity was the most sensitive vigor test to identify seed deterioration.

Temporary storage of jussara palm seeds: effects of time, temperature and pulp on germination and vigor

Seeds of jussara palm (Euterpe edulis Mart.) are recalcitrant, presenting low longevity, high sensitivity to dehydration and to low temperatures of storage. Temperature conditions for temporary preservation of those seeds, with and without pulp, were studied. Mature fruits were harvested from 24 plants belonging to the palm collection of the Instituto Agronomico (IAC) located at Ubatuba, Sao Paulo State, Brazil, and taken in moisture-proof containers to the Universidade Estadual de Sao Paulo, in Botucatu, Sao Paulo State. Half of the fruits were shelled and the seeds stored, with and without pulp, in sealed plastic bags (20 µm thick) maintained in chambers with temperatures of 5; 10; 15 and 20-30oC. Samples for the quality tests were taken at 0; 3; 6; 9 and 12 days after fruit harvest. Seeds stored with pulp were immediately shelled before test installation. Several characteristics were evaluated, especially seed water content, germination rate, seedling length and dry matter. There is a positive after-ripening effect on Euterpe edulis seeds. A period of storage of 9 to 12 days, after fruit harvest and before sowing, favored germination and vigor of jussara seeds. These effects were higher in shelled seeds when compared to unshelled ones. Short-term storage temperatures ranging from 5 to 20-30oC are equally adequate for the preservation of seeds without pulp, but should not exceed 20oC for those with pulp, since a decrease in germination and vigor, and an increase in rotted germinative button and dead seeds were observed at 20-30oC temperature.

Umedecimento do substrato na emergência e vigor de plântulas de pupunheira

A germinacao rapida e uniforme das sementes, seguida por pronta emergencia das plântulas sao caracteristicas altamente desejaveis na formacao de mudas. O objetivo deste trabalho foi verificar o efeito de diferentes niveis de umedecimento do substrato vermiculita sobre a porcentagem de emergencia e o vigor de plântulas de pupunheira. O umedecimento da vermiculita com agua nas quantidades de 60 a 90 ml/100 g de substrato (de 0,6 a 0,9 x o peso deste em agua ou 77,6 a 86,7% da capacidade de retencao do substrato em agua, respectivamente) resultaram na maior porcentagem de emergencia das plântulas. O umedecimento com 90 ml agua/100 g de vermiculita resultou em maior velocidade de emergencia e vigor de plântulas (comprimento, diâmetro e massa).

Densidade radicular de progênies de pupunheira em função de adubação NPK

The efficient use of fertilizers requires a knowledge of their effects, not only on shoot biomass, but also on below-ground biomass, to identify an adequate fertilization level from the point of view of a better partition between both. Dried root mass per soil volume has been used, especially in perennial crops, as a substitute for estimates of root biomass. With this objective, the root density of three progenies of the pejibaye palm (Bactris gasipaes Kunth) was studied under a combination of four nitrogen (0 to 400 kg/ha/year of N), phosphorus (0 to 200 kg/ha/year of P2O5) and potassium (0 to 200 kg/ha/year of K2O) doses, in a field experiment. The area was located at Ubatuba, SP, Brazil, in an allic alluvial soil, corrected by liming. The samples were collected during the first heart of palm harvest (October, 1993), when the plants (cultivated in a 2 x 1 m spacing) were two years old. Samples were collected, between and within planting rows, using a root-soil auger sampler, 50 cm from the main stem and at a 0-20 cm soil depth. There were differences among genotypes (GE), with progenies 2 and 3 showing, on average, higher root densities than progeny 1 (5.15 and 6.20, against 2.61 g/dm3, respectively). The interaction GE x PO (sample position) was significant: progenies 1 and 2 showed the highest root densities within planting rows (3.30 and 6.60 g/dm3 within row, against 1.92 and 4.70 g/dm3 between rows, respectively), while progeny 3 showed an inverse order (5.57 g/dm3 in the within row, and 6.84 g/dm3 between rows). There was a positive linear response to applied potassium (R2 =0.93 to 0.97), with increments between minimum and maximum doses varying from 18 to 28%. There was no isolated significant effect of P, while increasing doses of N provided a positive and significant linear effect, more evident in progeny 1 (averages of 2.26, 2.39, 2.62 and 3.16 g/dm3 for the doses 0, 100, 200 and 400 kg/ha/year of N, respectively). There was no significant interaction between GE and fertilizers (NPK), except for GE x N x P. Although the responses varied with progeny, higher root density was always found at high nitrogen doses.

Híbridos interespecíficos de palmiteiro (Euterpe oleracea x Euterpe edulis)

Compararam-se o desenvolvimento vegetativo e a producao de hibridos de palmiteiro (Euterpe oleracea x E. edulis) com seus genitores, em duas condicoes diferentes de cultivo, na regiao de Ubatuba, SP. Em ambas as situacoes, os hibridos apresentaram vigor e precocidade aliados a capacidade de regeneracao, mostrando-se superiores a populacao parental em crescimento vegetativo e producao de palmito. Embora o material ainda nao seja homogeneo, os hibridos interespecificos revelaram grande potencialidade para serem usados no cultivo racional do palmiteiro.

Atividade da redutase de nitrato em mudas de pupunheira (Bactris gasipaes)

The nitrate reductase enzyme (EC 1.6.6.1) is the main responsible enzyme for the assimilation of nitrogen by plants and its activity is strongly affected by the soil water availability. This feature allows the use of this enzyme to evaluate plants in different environmental conditions. The objective of this study was to standardize the methodology to evaluate in vivo the nitrate reductase activity in leaves and roots of nine months and one year old peach palms (Bactris gasipaes). The plants were cultivated in a nursery and the essays were conducted according to the classical method of in vivo analyses. The experimental design was entirely randomized with six repetitions. The results showed that maximum nitrate reductase activity for leaves was obtained with an incubation time of 60 minutes, pH 7, temperatures from 35 to 37°C and, nitrate concentrations between 28 and 30mmol L-1. The nitrate reductase enzyme activity was higher in nine months than in one year old palms. The peach palm leaves showed higher enzyme activity than roots. The nitrate reductase activity varied during the day, with maximum activity at 10:00 hs, indicating an influenceby light and leaf water potential.