Maria Luiza Sant'anna Tucci

Erythrina speciosa (Leguminosae-Papilionoideae) under soil water saturation: morphophysiological and growth responses.

BACKGROUND AND AIMS Erythrina speciosa is a Neotropical tree that grows mainly in moist habitats. To characterize the physiological, morphological and growth responses to soil water saturation, young plants of E. speciosa were subjected experimentally to soil flooding. METHODS Flooding was imposed from 2 to 4 cm above the soil surface in water-filled tanks for 60 d. Non-flooded (control) plants were well watered, but never flooded. The net CO(2) exchange (A(CO2)), stomatal conductance (g(s)) and intercellular CO(2) concentration (C(i)) were assessed for 60 d. Soluble sugar and free amino acid concentrations and the proportion of free amino acids were determined at 0, 7, 10, 21, 28 and 45 d of treatments. After 28, 45 and 60 d, dry masses of leaves, stems and roots were determined. Stem and root cross-sections were viewed using light microscopy. KEY RESULTS The A(CO2) and g(s) were severely reduced by flooding treatment, but only for the first 10 d. The soluble sugars and free amino acids increased until the tenth day but decreased subsequently. The content of asparagine in the roots showed a drastic decrease while those of alanine and gamma-aminobutyric increased sharply throughout the first 10 d after flooding. From the 20th day on, the flooded plants reached A(CO2) and g(s) values similar to those observed for non-flooded plants. These events were coupled with the development of lenticels, adventitious roots and aerenchyma tissue of honeycomb type. Flooding reduced the growth rate and altered carbon allocation. The biomass allocated to the stem was higher and the root mass ratio was lower for flooded plants when compared with non-flooded plants. CONCLUSIONS Erythrina speciosa showed 100 % survival until the 60th day of flooding and was able to recover its metabolism. The recovery during soil flooding seems to be associated with morphological alterations, such as development of hypertrophic lenticels, adventitious roots and aerenchyma tissue, and with the maintenance of neutral amino acids in roots under long-term exposure to root-zone O(2) deprivation.

Germinação de sementes e desenvolvimento inicial de plântulas de achachairu

The achachairu (Garcinia sp), a fruit widely grown in Bolivia, has been commercialized in Brazil for many years. The fruit is globular-oblong shaped, with a white succulent pulp, mucilaginous texture and a well balanced sweet-acid flavor (oBrix 15; pH 4.1). Due to the increasing interest in its cultivation in Brazil, this work was carried out aiming to study the seeds germination and seedling development throughout the first 12 months after seed emergence. The seeds, after being extracted from full ripe fruits were placed in a B.O.D. type chamber, under the following temperatures: 25, 30, 20-30 oC, as well as under room temperature (25±2 oC). The best result was given by the steady temperature of 30oC, with a germination of 92% and a germination speed index (GSI) of 0,255. At room temperature, seeds germination was low (30%), with a GSI of 0,015. Seedling development at greenhouse conditions was very slow mainly throughout the first weeks post emergence. The first pair of leaves appeared 25 days after seedling emergence, when seedlings averaged 8cm. From the eighth month on, many lateral branches were burst out, from the seedling medial portion towards the apical one.

Seasonal growth variation of peach palms cultivated in containers under subtropical conditions

A pupunheira (Bactris gasipaes Kunth) e cultivada no Estado de Sao Paulo, Brasil, sob condicoes de variacao estacional do clima, particularmente temperatura e precipitacao pluviometrica, com possiveis efeitos na fisiologia das plantas. Recentemente, devido ao crescente interesse em se realizar experimentos sobre a fisiologia da especie, tem havido necessidade de cultiva-la sob condicoes experimentais mais controladas. Com o objetivo de estudar a variacao estacional do crescimento de pupunheiras, bem como a possibilidade de cultiva-las em recipientes ate a colheita, para a realizacao de futuros experimentos fisiologicos, foi executado este trabalho, em Campinas, SP, com 40 pupunheiras inermes. Um ano apos a germinacao, as mudas foram transplantadas em recipientes plasticos de 80 L, em espacamento 2 x 1 m, dispostos em quatro linhas de dez plantas. O desenvolvimento vegetativo foi avaliado mensalmente, em todas as plantas, por medidas de altura da haste principal, numero de folhas funcionais, numero de perfilhos e comprimento da raquis. Foi observada estacionalidade de crescimento em altura e diâmetro, bem como em comprimento da folha mais jovem e na evolucao do numero de folhas. Apos dois anos, as plantas apresentavam altura media de 230 cm, e media de 6 folhas e 11,7 perfilhos. Correlacoes positivas (P < 0.001) foram observadas entre variaveis de crescimento e as medias de temperatura, precipitacao pluviometrica, bem como insolacao vigente nos 30, 60, 90 ou 120 dias anteriores as mensuracoes. As pupunheiras puderam ser cultivadas em recipientes ate a primeira colheita, sem restricoes ao crescimento.

Gas exchanges in peach palms as a function of the spad chlorophyll meter readings

The close relationship between the chlorophyll-meters readings and the total chlorophyll and nitrogen contents in leaves, has allowed their evaluation both in annual and perennial species. Besides, some physiological events such as the CO2 assimilation have also been estimated by chlorophyll meters. This work was carried out aiming to evaluate the gas exchanges of peach palms as a function of the chlorophyll SPAD-Meter readings. Three year-old peach palms from Yurimaguas, Peru were studied in Ubatuba, SP, Brazil, spaced 2 x 1 m in area under a natural gradient of organic matter which allowed four plots to be considered, according to the peach palms leaves colors, from light yellow to dark green. The SPAD readings and the stomatal frequency of leaflets were evaluated. The photosynthetic photon flux density (PPFD, μmol m-2 s-1), the leaf temperature (Tleaf, oC), the CO2 assimilation (A, μmol m-2 s-1), the stomatal conductance (gs, mol m-2 s-1), the transpiration (E, mmol m-2 s-1) and the intercellular CO2 concentration (Ci, μmol mol-1) were evaluated with a portable infrared gas analyzer (LCA-4, ADC BioScientific Ltd., Great Amwell, U.K.). A linear increase in the CO2 assimilation as a function of the SPAD readings (y = -0.34 + 0.19x, R2 = 0.99), indicates that they can be a rapid and cheap complementary method to evaluate in peach palms some important physiological events, such as CO2 assimilation.

CRESCIMENTO DE MUDAS DE PUPUNHEIRA ( Bactris gasipaes Kunth) UTILIZANDO RESÍDUO DE MINERAÇÃO DE AREIA COMO COMPONENTE DE SUBSTRATOS

O objetivo deste trabalho foi avaliar o crescimento de mudas de pupunheira quando utilizado o residuo fino de mineracao de areia na composicao de substratos. O experimento constou de cinco tratamentos, sendo quatro composicoes de diferentes proporcoes de residuo de mineracao de areia e casca de arroz carbonizada: 1:0; 3:1; 1:1; 1:3 e um substrato padrao composto por latossolo amarelo podzolico alico e esterco de bufalo curtido, na proporcao 3:1. Utilizou-se o delineamento experimental de blocos ao acaso com cinco repeticoes e 10 mudas por parcela. Repicou-se uma plântula de pupunheira por recipiente (sacos plasticos de polietileno preto de 8 x 20 cm, volume 1,1 L), os quais foram preenchidos com os diferentes substratos. Foram determinadas mensalmente as variaveis diâmetro do coleto, altura da haste, numero de folhas e taxa de crescimento relativo e, apos 180 dias da repicagem, os valores SPAD (Soil and Plant Analysis Development), din âmica da assimilacao de CO2, da transpiracao e da condutividade estomatica. O residuo de mineracao de areia puro como substrato nao proporcionou mudas de qualidade, visto que esse material apresenta alta densidade e baixa granulometria. Seu uso pode ser indicado como um dos componentes de substratos, pois as plantas que cresceram nas misturas de residuo e casca de arroz carbonizada apresentaram resultados semelhantes ao do considerado padrao.