Marcelo de Almeida Guimarães

Reciprocal grafting separates the roles of the root and shoot in zinc hyperaccumulation in Thlaspi caerulescens

The extreme phenotype of zinc (Zn) hyperaccumulation, which is found in several Brassicaceae species, is determined by mechanisms that promote elevated Zn tolerance and high Zn accumulation in shoots. We used reciprocal grafting between a Zn hyperaccumulator, Thlaspi caerulescens, and a Zn nonaccumulator, Thlaspi perfoliatum, to determine the relative importance of roots and shoots in Zn hyperaccumulation and hypertolerance. Leaves from plants with a T. perfoliatum rootstock and a T. caerulescens shoot scion did not hyperaccumulate Zn, whereas plants with a T. caerulescens rootstock and a T. perfoliatum shoot scion did hyperaccumulate Zn. However, although leaves from plants with a T. caerulescens rootstock and a T. perfoliatum shoot scion hyperaccumulated Zn, at high Zn loads these leaves showed significant symptoms of Zn toxicity, unlike leaves of self grafted T. caerulescens. Hyperaccumulation of Zn in leaves of the hyperaccumulator T. caerulescens is pri-marily dictated by root processes. Further, the mechanisms controlling Zn hypertolerance in the hyperaccumulator T. caerulescens are driven primarily by shoot processes.

Produção e sabor dos frutos de tomateiro submetidos a poda apical e de cachos florais

The effect of top-shoot and floral cluster pruning on the production and flavor of the tomato fruits were experimentally evaluated (May to November of 2002). The experimental design was of randomized blocks, with five treatments, seven replications, and eight-plant plots. Seedlings from cultivar Kindyo of indeterminate growth habit, were used. Treatments were: (A) pruning of the 1st floral cluster and top-shoot pruning above the 7th floral cluster; (B) same as A, but without top-shoot pruning and with pruning of the floral clusters above the 7th cluster; (C) without pruning the 1st floral cluster, but with top-shoot pruning above the 6th floral cluster; (D) same as C, but without top-shoot pruning and with pruning of floral clusters above the 6th.; (E) without top-shoot and floral cluster pruning, but evaluating only the first six floral clusters. Tomato fruits were harvested, graded and weighed in a week basis, after reaching maturity (100% red). Data were submitted to variance analysis and Tukeys test (p<0.05). Pruning of the 1st floral cluster was detrimental for commercial production of tomato fruits. The preservation of plant growth in combination with pruning of floral cluster above the sixth, without pruning the first floral cluster (treatment D), significantly increased the production of large fruits (101.5 t ha-1) in relation to the other treatments (treatment A: 74.9; B: 71.4; C: 80.3; E: 78.9 t ha-1). However, for commercial production, treatment D (127.7 t ha-1) significantly differed only from treatments A and B (106.6 and 99.4 t ha-1, respectively). For total production, flavor, oBrix, and pH, whose averages were respectively 149.4 t ha-1; 13; 4,32%, and 4,34, there were no significant differences.

Physiological quality of sesame seeds produced from plants subjected to water stress

Germination and seed vigor may be influenced by several factors, such as water stress during production, which affect crops differently according to the phenological stage of the plant. The aim of this study therefore was to evaluate the physiological quality of sesame seeds from plants subjected to water stress at different phenological stages. To this end, sesame plants were subjected to water stress at the following stages: I - germination to the start of vegetative growth (T1); II - vegetative growth to flowering (T2); III - flowering to pod formation (T3); IV - fruit maturation (T4); also for stress at all stages (T5) and full irrigation (T6). By weighing and daily irrigation of the containers, levels were kept at 50% of pot capacity (CV) for treatments with water deficit, and at 100% CV for treatments with no deficit. At 90 days after planting, the plants were harvested. The seeds were evaluated by germination test, first germination count, germination speed index, mean germination time, accelerated aging, electrical conductivity, seedling emergence, emergence speed index, mean time of emergence, seedling length and seedling dry weight. Sesame seeds from plants grown under water deficit display lower physiological quality. Between germination and the start of vegetative growth, and between flowering and fruit formation, the sesame is more sensitive to water stress, so that water limitation during these periods results in the production of seeds of low physiological quality.

Genetic divergence of tomato subsamples

Understanding the genetic variability of a species is crucial for the progress of a genetic breeding program and requires characterization and evaluation of germplasm. This study aimed to characterize and evaluate 101 tomato subsamples of the Salad group (fresh market) and two commercial controls, one of the Salad group (cv . Fanny) and another of the Santa Cruz group (cv. Santa Clara). Four experiments were conducted in a randomized block design with three replications and five plants per plot. The joint analysis of variance was performed and characteristics with significant complex interaction between control and experiment were excluded. Subsequently , the multicollinearity diagnostic test was carried out and characteristics that contributed to severe multicollinearity were excluded. The relative importance of each characteristics for genetic diver gence was calculated by the Singh’s method (Singh, 1981), and the less important ones were excluded according to Garcia (1998). Results showed large genetic divergence among the subsamples for morphological, agronomic and organoleptic characteristics, indicating potential for genetic improvement. The characteristics total soluble solids, mean number of good fruits per plant, endocarp thickness, mean mass of marketable fruit per plant, total acidity , mean number of unmarketable fruit per plant, internode diameter , internode length, main stem thickness and leaf width contributed little to the genetic divergence between the subsamples and may be excluded in future studies.

Inducing flowering in Noccaea caerulescens (J. & C. Presl) F. K. Mey (Brassicaceae), a species having high heavy-metal accumulation.

Noccaea caerulescens (J. & C. Presl) F. K. Mey (Brassicaceae) is a plant widely used in studies of the high accumulation of such metals as Cd, Ni, and Zn. Considered a biennial species, propagated mainly by seed, it presents a long period for the generation of new individuals, which significantly hampers the development of new studies of this species. Based on the above, the objective of this work was to develop a protocol to induce early flowering and abundant seed-production in N. caerulescens. Plants of this species were therefore grown and developed in a controlled environment (growth room and cold chamber), and then submitted to different treatments composed of combinations of the following environmental conditions: photoperiod (8 or 12 hour of light - 100 µmol m-2 s-1), temperature (4 or 21 °C), time of exposure to the above conditions (6 or 8 weeks) and application of different concentrations of GA3 (0, 15, 30 and 60 µg µL-1). The work was carried out in a completely randomized design, with twenty plants per treatment being analyzed. The following characteristics were evaluated: a) Percentage of flowering (%); (b) Length of main cluster (cm); and (c) seed production (g pl-1). It can be seen that the temperature of 4oC was essential for inducing flowering and seed-production in N. caerulescens, with the time of exposure of the plants to this temperature being very important to potentialise seed production and longer periods of exposure to low temperatures being preferred.

Seleção de genótipos de Lactuca sativa L. para a produção com adubação orgânica

The aim of this study was to evaluate the adaptation of different genotypes of lettuce (Lactuca sativa L.) to organic farming systems. Eighteen accesses belonging to the Germoplasm Bank (BGH - UFV) were evaluated and compared with two commercial cultivars, Regina de Verao and Crespa Grand Rapids. The experiment was conducted in a greenhouse with three replications. The accesses were compared on substrates made of soil with either mineral or organic fertilizers. Plants were grown in 3 dm3 polystyrene pots filled with 2.5 dm3of soil. The substrate with mineral fertilizer was prepared with conventionally cultivated soil and mineral fertilizer, according to lettuce crop recommendations, based on soil analyses. The substrate with organic fertilizer was prepared with organically managed soil and fertilized with 50 t.ha-1 of organic compost. At harvest, plant morphological characteristics and leaf fresh and dry weights were evaluated. A great variability of forms, sizes and colors were observed among the genotypes. Accesses BGH 2625, BGH 118 and the cultivar Regina de Verao showed the greatest adaptation to organic environment. The genotypes showed good qualitative characteristics and yield and, therefore, were selected as possible sources of adaptation to this environment.

Production of cocona and jurubeba seedlings in different types of containers

The effect of different containers was evaluated to produce cocona seedlings (Solanum sessiliflorum) and jurubeba (Solanum paniculatum). The experiment was performed in the mesoregion of Alto Solimoes, in Benjamin Constant, Amazonas state, Brazil, in a particular production area. The seeding was done in black holed polyethylene bags and polystyrene trays with 128, 200 and 288 cells with volumes of 250.00; 32.61; 21.60 and 9.88 cm3, respectively. We adopted a completely randomized design with four containers, four replicates, being assessed five plants per replicate. The seedlings of cocona were evaluated at 27, 38, 45 and 52 days after sowing (DAS) and of jurubeba at 38, 45, 52, 59 and 66 DAS. We evaluated the number of leaves; length of the main root, the aerial and total parts of the plant, fresh and dry matter of the main root, fresh and dry matter of the aerial part. There was no difference on the number of leaves of jurubeba at 45 and 66 DAS; there was no difference on the number of leaves of cocona at 52 DAS; there occurred a greater number of leaves of cocona when seeded on trays containing 200 cells; The other characteristics for both species presented higher values when the seeding was done in the plastic bags, at all evaluation dates.

Morphological and productive aspects of lettuce in low altitude and latitude

Lettuce is considered a crop of mild climate and its production in regions of low altitude and latitude is impaired due to the high temperatures and the predominance of long days. Therefore, the aim of this study was to evaluate the behavior of lettuce cultivars in such conditions. An experiment was conducted at the Horta Didatica of the Federal University of Ceara, Campus do Pici, in Fortaleza. Nine lettuce cultivars from three commercial groups were used and distributed in a randomized block design, with four replications. The following qualitative traits were evaluated: bolting, head formation, leaf texture, anthocyanin and phytosanitary status for pest and disease infestation. Regarding the quantitative traits, plant height, plant diameter, fresh marketable weight (FMW), and non-marketable (FNMW) total fresh weight (TFW), dry marketable weight (DMW) and non-marketable (DNMW), total dry weight, chlorophyll a, chlorophyll b, chlorophyll a/b ratio. Data were submitted to analysis of variance and, later, grouping test was performed. None of the cultivars presented head formation but all presented early bolting. The cultivars showed no difference for FMW, however, Baba de Verao produced almost 72% more than Repolhuda Brasil from the same group. Regarding FMW, the most productive cultivars were Baba de Verao, Crespa para Verao, Americana Delicia, Crespa Repolhuda and Kaiser. However, Baba do Verao and Crespa stood out for DMW.

Isolation and characterization of gene sequences expressed in cotton fiber

Cotton fiber are tubular cells which develop from the differentiation of ovule epidermis. In addition to being one of the most important natural fiber of the textile group, cotton fiber afford an excellent experimental system for studying the cell wall. The aim of this work was to isolate and characterise the genes expressed in cotton fiber (Gossypium hirsutum L.) to be used in future work in cotton breeding. Fiber of the cotton cultivar CNPA ITA 90 II were used to extract RNA for the subsequent generation of a cDNA library. Seventeen sequences were obtained, of which 14 were already described in the NCBI database (National Centre for Biotechnology Information), such as those encoding the lipid transfer proteins (LTPs) and arabinogalactans (AGP). However, other cDNAs such as the B05 clone, which displays homology with the glycosyltransferases, have still not been described for this crop. Nevertheless, results showed that several clones obtained in this study are associated with cell wall proteins, wall-modifying enzymes and lipid transfer proteins directly involved in fiber development.

Substrates and containers for the development of Brassica pekinensis L. seedlings

The aim of this study was to evaluate the development of Chinguensai (Brassica pekinensis L.) seedlings, under different formulations of substrates and sizes of containers, in Fortaleza, Ceara. For this, two studies were conducted in factorial design with randomized blocks and four replicates. The first study was conducted in a factorial (4 × 4) design. Four substrate formulations (powder-type coconut fiber; carbonized rice hull and earthworm casting) had the following proportions: S1 (1:1:1); S2 (0:1:1); S3 (1:0:1); and S4 (0:0:1) by volume basis (v/v) and four evaluation dates (22, 27, 34 and 41 days after sowing — DAS). The second study was conducted in a factorial (3 × 4) design with three types of containers with different cell volumes (31, 18 and 11 cm3) and four evaluation dates (22, 27, 34 and 41 DAS). The fresh and dry weight of the shoot and root systems was evaluated. Both studies showed no interaction between the variables, with differences noted for substrate factors, containers and times in all traits. In the first study, the earthworm compost resulted in the highest yield of fresh and dry seedling weight. In the second study, the container with 31 cm3 of cell volume showed the highest production of fresh and dry weights. The results showed that the substrate composed solely of earthworm humus and with the use of trays with 31 cm3 of cell volume provided seedlings of Chinguensai with the optimal production for transplanting 41 DAS.