Dierlei dos Santos

Teores de carboidratos em limeiras ácidas 'Tahiti' tratadas com paclobutrazol

ABSTRACT – The Placobutrazol (PBZ) can delay the growth and induce the flowering of citrus through the inhibition of biosynthesisof gibberellins. Besides, other features of the plants can be influenced by the application of PBZ, as well as the concentrations anddistribution of carbohydrates. The work was carried out aiming to study the possible relationships between concentrations anddistribution of carbohydrates in the plant and application of PBZ in acid lime tree ‘Tahiti’, grafted on lemon tree ‘Cravo’ and cultivatedin pots of five litters. The PBZ was applied in plants conducted in a growth chamber, under controlled temperature (28oC day/ 20o Cnight), and photoperiod of 16 hours with light, with photosynthetic photons flow of about 170 µmol m -2 s -1 . The application of PBZcaused significant reductions on the levels of carbohydrates in the leaves because they induced the flowering in the acid lime tree‘Tahiti’. The application of paclobutrazol resulted in the accumulation of reserves of carbohydrates in the roots.Terms for index: Citrus latifolia Tanaka, phytoregulators, hydric stress.

Slow-release and organic fertilizers on early growth of Rangpur lime

Slow-release and organic fertilizers are promising alternatives to conventional fertilizers, as both r educe losses by leaching, volatilization and problems of toxicity a nd/or salinity to plants. The objective of this wor k was to evaluate the effect of different rates of the organic fertilizer Humato-Macota ® compared with the slow-release fertilizer Osmocote ® on the growth and nitrogen content in the dry matte r of Rangpur lime. A field experiment was conducted in a factorial completely randomized design with an additional tre atment (4 x 4 +1). The first factor consisted of fo ur HumatoMacota ® rates (0, 1, 2, and 3%) applied to the substrate; the second factor consisted of the same Humato-Macota ® concentrations, but applied as fortnightly foliar s prays; the additional treatment consisted of applic ation of 5 kgm -3 Osmocote ® 18-05-09. Means of all growth characteristics (pla nt height, total dry matter, root/shoot ratio and l eaf area) and the potential quantum yield of photosystem II ( Fv/Fm) were higher when plants were fertilized with the slowrelease fertilizer. The organic fertilizer applied alone did not meet the N requirement of Rangpur lime.

Population dynamics of sharpshooters species transmitter of citrus variegated chlorosis (CVC) in Viçosa-MG

Os objetivos deste trabalho foram avaliar a presenca e a dinâmica populacional, ao longo do ano, de cigarrinhas transmissoras da CVC, no municipio de Vicosa - MG. As coletas foram realizadas no periodo de agosto de 2003 a julho de 2004, com auxilio de armadilhas adesivas amarelas e com rede entomologica (puca). Das onze especies comprovadamente capazes de transmitir a CVC, foram encontradas nove. O numero total de cigarrinhas capturadas foi de 2.966, sendo 2.805 nas armadilhas e 161 no puca. As tres especies da familia Cicadellidae mais expressivas em numero de insetos foram Bucephalogonia xanthophis (36,6% capturados na rede entomologica e 34,7% na armadilha), Dilobopterus costalimai (9,9% capturados na rede entomologica e 11,3% na armadilha) e Acrogonia citrina (6,8% capturados na rede entomologica e 7,4% na armadilha). No mes de novembro, foram coletadas 378 cigarrinhas, correspondendo ao mes de maior incidencia, sendo que 292 dessas foram coletadas na primeira quinzena, concorrendo para um pico populacional. Nao houve diferenca significativa entre o numero medio de cigarrinhas coletadas no interior e na periferia da area.

Micropropagação da bananeira 'Maçã', cultivada in vitro em diferentes volumes de meio líquido

Micropropagation of ‘Maca’ banana tree, cultivated in vitro in different volumes of liquid medium This study aimed to evaluate the effect of different volumes of stationary MS liquid medium on the in vitro multiplication rate and development of banana ‘Maca’ explants. During the multiplication phase, were used microrhizome of the cultivar ‘Maca’ (AAB), derived from pre-established plants on solid culture medium, which were standardized for size. The experimental design was a completely randomized with seven treatments and ten replicates, and the plot consisted of four explants. The treatments were different volumes of the liquid stationary medium (5, 10, 15, 20, 25, 30 mL) and 30 mL of semi-solid medium (standard). Microplants produced at the end of the third subculture were transferred to a growth and rooting medium. The experiment consisted of the same treatments and design, and each plot comprises four explants. The different liquid volume and the semi-solid did not alter the explants multiplication rate. It is possible to produce microplants of banana ‘Maca’ in vitro in liquid stationary medium, being the optimal volume of the 25 mL per flask.

Qualidade fisiológica de sementes de citros durante o armazenamento em ambiente refrigerado

Aimed to evaluate the effect of storage on emergence and force of the rootstocks Citradia 1708, Citrandarin 1710, Citrange Carrizo, Rangpur lime, Trifoliata Limeira, Rangpur x Swingle 1707 seeds stored in High density polyethylene (HDPE) at 5-7°C and relative humidity of 70% for 210 days. The emergence, emergence speed index and seed moisture content were performed each 30 days. The experimental design was a completely randomized design with four replications. The storage in that conditions cited showed that the seeds of Rangpur with moisture content inferior to 9% still showed 66.94% and 2.03 for germination and IVE, respectively. For the maintenance of the viability of seeds of the rootstocks Citradia 1708, Citrandarin 1710, Citrange Carrizo, Rangpur x Swingle 1707, moisture content could be kept between 35-40%. Seed viability of the rootstocks Rangpur x Swingle 1707, Citradia 1708 and Citrange Carrizo was maintained for until 150 days.