Marichel Canazza de Macedo

Biometry of fruit and seeds and germination of Magonia pubescens ST.Hil (SAPINDACEAE)

Magonia pubescens is a common native tree species of Brazilian savanna with a great utilization potential because of its economic and ecologic characteristics. The aim of this work was to evaluate the biometrical characteristics of fruit and seeds of this species and its germination potential. It was studied 28 fruit and 293 seeds originated from trees placed in Aquidauana - MS. The study was conducted in the Vegetable Physiology Laboratory and nursery conditions belonged to Faculdade de Ciencias Agrarias (FCA) of Universidade Federal da Grande Dourados (UFGD). There was a large variation in the size, weight and the seed-number of the fruit that presented middle values 6,66 cm of length, 8,14 cm of diameter, 248,21g fresh mass and 13,14 seeds. On the other hand, the seed size variation was smaller than the fruit size variation. The seeds presented middle values 4,81 cm of length, 8,44 cm of width and 3,5 of fresh mass. For the germination study, the seeds received the following treatments: 1) KNO3 1% 24h; 2) KNO3 2% 24h; 3) GA 500 mg. L -1 24h; 4) GA 250 mg L-1 24h; 5) Water 24h; 6) Control. The experiment was set up according to a three-replicate randomized complete design with 6 treatments. The treatment of immersion in water for 24 hours promoted the highest values of emergence percentage (80%). The gibberellins promoted the highest values of aerial part height (meddle of 14,7cm). The highest values of fresh and dry aerial part matter were observed in seedlings originated from seeds treated with GA 500 mg. L -1 (1,26 and 0,24g, respectively). The highest values of fresh and dry cotyledons matter were observed in seedlings originated from seeds treated with KNO3 1% 24h (7,63 and 1,81, respectively). It is recommended to pre-soak of the seeds in water or GA for 24 hours to obtain a greater number of seedlings.

Produção de mudas de ipê-branco em diferentes substratos

Objetivou-se, com este trabalho, avaliar a emergencia de plântulas e o crescimento no viveiro de mudas de ipe-branco (Tabebuia roseo-alba (Ridl.) Sandwith) em diferentes substratos. Foram realizados dois experimentos independentes. O estudo da emergencia foi realizado em seis substratos: 1- Plantmax® - P; 2- vermiculita - V; 3- areia - A; 4- solo + areia - SA (1:1); 5- solo + casca de arroz carbonizada - SC (1:1); 6- solo + areia + casca de arroz carbonizada - SAC (2:1:1) (v/v), sendo utilizado o delineamento experimental em blocos casualizados (DBC) com tres repeticoes. O estudo do crescimento no viveiro foi realizado em DBC com cinco substratos e cinco repeticoes, sendo utilizados os seguintes substratos: 1- solo + areia - SA (1:1); 2- solo + cama de frango semidecomposta - SCF (1:1); 3- solo + casca de arroz carbonizada - SC (1:1); 4- solo + areia + cama de frango semidecomposta - SACF (1:1:1); 5- solo + areia + casca de arroz carbonizada - SAC (1:1:1) (v/v). Os maiores valores de porcentagem final de emergencia, indice de velocidade de emergencia e altura das plântulas foram observados nos substratos P, V, SC e SAC. Os maiores valores de altura, diâmetro do colo, indice de clorofila, area foliar, comprimento da maior raiz e massa seca da parte aerea e radicular das mudas foram observados nos substratos SACF e SCF. Recomenda-se a utilizacao de P, V, SC ou SAC para germinacao e emergencia de plântulas e SACF ou SCF para a producao de mudas de ipe-branco.

Substratos e intensidades de luz no cultivo de orquídea denfal

The influence of light and alternative substrates to fern tree fiber was evaluated on the development and flowering of Dendrobium phalaenopsis var. schroederianum x Dendrobium bigibbum var. compactum plants. The experiment was carried out from October 2007 to August 2008. Four-year old plants from in vitro cultivation, and acclimatized in nursery with light intensities of 12,800, 8,300, 6,200, 5,300 and 4,500 lux, were used. Plants were planted in plastic vases filled with charcoal, coconut fiber or a mix of charcoal + coconut fiber as substrate. During the experimental period, the reduction of fresh mass (%) and diameter of pseudobulbs, sprouting (%), beginning of flowering, plants with flowers (%), length of the flower stem, flower buds (no), diameter of flowers and time of flowering were evaluated. The smallest reduction of fresh mass and of diameter were observed under 12,800 lux. For sprouting, the highest values were observed with charcoal substrate under 12,800 lux, or with coconut fiber substrate and charcoal + coconut fiber substrate under 4,500 lux. This orchid should be cultivated with charcoal under 12,800 lux, since the highest percentage of plants with flowers, number of buds per plant, diameter of flowers and length of the flower stem were produced under those conditions.

Aclimatização de Brassavola tuberculata com a utilização de ANA em diferentes substratos

One of the most limiting factors of orchid in vitro culture is the acclimatization. Thus the aim of this study was to evaluate the survival and initial growth of the Brassavola tuberculata (Orchidaceae) using naphthalene acetic acid (NAA), and different substrates during acclimatization. Plants were obtained from in vitro culture, previously immersed for 10 seconds in NAA solutions (0.0; 0.5; 1.0; 1.5; 2.0; 2.5; 3.0; 4.0 or 4.5 mg/L), and planted in plastic containers containing as substrate sphagnum, coconut fiber or a mix of sphagnum + coconut fiber 1:1 (v:v). The experiment was carried out in a completely randomized design, and the treatments were arranged in factorial 3x10, three substrates and 10 NAA concentrations, with 10 replications of one plant. After staying for 210 days in the greenhouse (83 µmol/m2/s) the plants were evaluated according to their survival, number of leaves, roots and offshoots, the length of the longest leaf and the longest root, fresh and dry mass of shoot and root. Increments of these variables in relation to the observed values during planting were also calculated. The substrates were evaluated according to their porosity, maximum water retention, substrate density, real density, electric conductivity and pH. The highest survival (67.7%) was obtained using the calculated concentration of 1.8 mg/L NAA which promotes the formation of efficient root system for the development of the species. The sphagnum is the most suitable substrate for the survival and early growth of B. tuberculata, in acclimatization phase.