The aim of this work was to study the physiological responses of three contrasting cultivars of sugar cane subject to water stress and rewatering, The experiment was carried out in a greenhouse, where the cultivars SP83-2847, SP80-1842 and SP81-3250 were grown in pots. The first assessment was done after 85 days of planting, then two treatments were implemented, i.e. without water stress (-D) and with water stress (+D) by withholding water for 15 days and rewatering imposed for 12 days after the stress period. Cultivars SP81-3250 and SP80-1842 showed a higher decline in the Fv/Fm ratio, leaf relative water content (RWC), leaf water potential (Ψw), SPAD index and photosynthetic pigments due to water deficit. Drought caused less damage in the physiology of the variety SP83-2847, and it still showed rapid recovery during rewatering, including for the stomatal conductance (gs), so this variety had better adaptation under this condition. The traits Fv/Fm, Ψw, RWC, SPAD index and photosynthetic pigments present as potential physiological indicators in order to select tolerant sugar cane cultivars to water deficit. The trait gs is more effective in differentiating the tolerant cultivars during rewatering.

The vegetation of the Caatinga has different types of unique landscapes, in which little is known. Considering the situation, this study aimed to perform a phytosociological survey in area of Ca atinga, located in Bom Jesus, Piauí. Were systematically re leased 15 quadratic plots with 400 m², with spacing of 80 m between plots and between lines. Within each sampli ng unit were measured all individuals with circumfe rence at breast height (CBH) ≥ 6 cm, as measured in these individuals the CBH and the total height. With this, it were calculated the phytosociological parameters, diamet er distribution and diversity index of Shannon-Wean er (H'). In this survey we sampled 640 individuals represent ing 36 species, which provided a density of 1600 in d ha -1 and an estimated basal area of 17.02 m² ha -1 . The species most representatives were Copaifera langsdorffi Desf., Ptyrocarpa moniliformis Benth., Pterodon abruptus (Moric.) Benth and Combretum glaucocarpum (Mart.) Eichl. , with about 43% of the sampled and 40% in the area of ecological importance. The result of the diversity index of Shannon-Weaner was 2.96 nats in d -1 .

This study had the objective to evaluate the action of aqueous (EAC), ethanolic (EEC) and decoction (EDC) extracts of juremapreta bark Mimosa tenuifloraand aqueousroot extract (EAR) on the control of alternaria black spot on watermelon, as well as evaluating the mode of action of these extracts, either by presenting toxicity to the pathogen and the ability to alter the metabolism of the host by activating protective enzymes. M.tenuiflora extracts were tested for inhibition of germination, mycelial growth and sporulation of A.cucumerina in vitro. Under controlled conditions (in vivo), the plants were sprayed with the four extracts in three concentrations (05, 4.0 and 10 mg.mL-1) 48 hours before inoculation. The evaluations were based on disease severity and determination of enzymatic activity. In the field the four extracts were sprayed at two concentrations (4.0 and 10 mg.mL-1), evaluating the severity of the disease with the help of descriptive scale. The EAC inhibited 100% germination, mycelial growth and sporulation of A.cucumerina in vitro. The EAC induced synthesis of β-1,3 glucanase and peroxidase, reducing 97% of the disease, in a controlled environment and 31% in the field, being superior to the other extracts and commercial fungicides: copper oxychloride which controlled 79% and 21% for environmental controlled and field respectively, and tebuconazole + trifloxystrobin which controlled 15% in the field. These extracts showed potential to control alternaria leaf spot is caused toxicity to the pathogen or by inducing resistance.

Some techniques can be used in order to promote the recovery of degraded areas like riverine ecosystems, and those with low impacts present a fast regeneration, through an ecological succession with no need for human intervention. It is necessary to study the use of techniques that contribute to the recovery of these ecosystems, such as soil bioengineering, which involves the use of biologically active elements working on soil stabilization, combined with inert elements such as concrete, wood, polymers, and geotextiles made with synthetic material or plant fibers. This work was carried out in order to evaluate planted species develop- ment and endemic species in the ecological succession, along the Paramopama river margin, located at the mu- nicipality of São Cristóvão, in Sergipe State, submitted to soil bioengineering techniques. Two types of geotex- tiles (Fibrax and Syntemax and 400 TF) arranged in two blocks and three treatments were tested, and the be- havior of the vegetation and efficiency of geotextiles were observed for a period of 11 months monitored by the floristic survey. The abundance of the species Crotalaria spectabilis and Calopogonium muconoides was stud- ied, and subsequently classified according to vegetation succession stage. The study revealed that the use of geotextile Syntemax 400 TF on the left bank promoted the greatest abundance of species, resulting in a greater vegetation cover, and consequently better protection of the slope. The geotextile Syntemax 400 TF was the most appropriate among the tested types, to promote the floristic recovery in the studied area and probably in those with similar soil-climatic conditions.

The crisphead lettuce is a greenery adapted to grow in regions with mild temperatures and lack of rain. The objective of this work was to evaluate the performance of crispheadlettuce cultivars (Del ícia, Teresa, Lucy Brown, Raider Plus, Mauren, Angelin), under tropical climate in city Cáceres-MT, in two h arvest times.The experiment followed the randomized comple te block , with four replications, were arranged in 6 x 2 factorial, being, six cultivars in the crisphead le ttuce and two harvest time. Was evaluated the total and com- mercial production, commercial dry matter mass, com pactness, plant diameter, “head” diameter, health a nd was estimated the proportion of stem in the “head”. The cultivars Teresa and Delícia exhibit the total pro duction upper in relationship the other cultivars evaluated in the experiment, with productions of 631.1 and 5 89.3 g plant -1 , respectively. The second harvest, at large, has w as upper in relationship first, with 607 g plant -1 . The cultivar Teresa, in the second harvest, exhibit the upper result from the commercial production with 4 79.6 and 483.6 g plant -1 , in the first and second harvest, respectively. Th e cultivar Teresa, in the second harvest, exhibit the upper evaluate from compactness. The cultivars Teresa and Delícia were the most suitable for culti vation from weather of Cáceres - MT, and the harvested mus t be performed at 67 days after sowing.

The evaluation of profitability of ‘Ponkan’ mandarin subjected to chemical thinning may constitute important information that allows the farmer to evaluate the feasibility of adopting the practice of management in his orchard. Thus, this study was developed with the aim to evaluate the profitability of the practice of chemical thinning in ‘Ponkan’ mandarin trees (Citrus reticulata Blanco). The work was carried out in 2009, 2010 and 2011 in an unirrigated orchard of ‘Ponkan’ mandarin, in the city of Perdões, the southern region of Minas Gerais, Brazil. Before the treatments, in October 2008, 80 plants we selected with abundant flowering on the entire canopy, so that all the mandarin trees could have production significant quantities of fruit. In half of the plants was not performed the chemical thinning and the other half was applied 600 mg L-1 of Ethephon, after the period of physiological fruit drop, in January 2009, January 2010 and January 2011, when these were at stage 25 to 30 mm in transverse diameter. At harvest, in June 2009, June 2010 and June 2011 were evaluated the production per plant (boxes of 22 kg) and estimated the productivity of plants subjected to the chemical thinning and plants that were not subjected to this practice. The profitability analysis was performed in a simplified manner considering the production costs of the orchard already deployed with the production stable. The practice of chemical thinning promoted superiority of 176% on the average profitability of 'Ponkan' mandarin trees.

Elevated productivity of castor and common bean in intercropping is obtained with the use of quality seeds, where boron plays an important role in plant nutrition. The objective of the this study was to evaluate the physiological quality of seeds of the common bean and castor grown in intercropping syste ms, subject to different sources and levels of boron. A completely randomized design was used in a 2 x 5 + 2 facto- rial scheme with four replications. Treatments cons isted of two sources of boron (borax = 11% B and bo ric acid = 17% B), combined with five boron doses (0.0, 0.5, 1.0, 2.0 and 4.0 kg ha -1 of B in the soil) in intercropping of the common bean with castor, plus additional treatm ents of common bean and castor in monoculture. It w as concluded that boric acid permitted for acquisition of common bean seeds with the highest germination per- centage when intercropped with castor. Use of the d ose of 1.5 kg ha -1 of boron in the soil resulted in acquisition of seeds of the common bean with vigor of 79% when intercropped with castor, regardless of the boron s ource. Employing 2.3 kg ha -1 of boron, with the source being either boric acid or borax, influenced the vigor of castor seeds produced when intercropped with the common be an. The addition of boron by soil fertilization, in de- pendent of the source used, did not affect the phys iological quality of common bean seeds or castor se eds pro- duced in monoculture.

The objective of this study was to evaluate the emergence and development of lettuce seed- lings, cv. Babá de Verão, when produced with organi c substrates made from sheep manure. The experiment was accomplished at a nursery in the Universidade F ederal Rural de Pernambuco (UFRPE), Unidade Acadêmica de Serra Talhada (UAST), Serra Talhada to wn, State of Pernambuco, during the month of April 2011. It was used a completely randomized design wi th four replications. The treatments were: T1 – com mer- cial substrate (Tropstrato HT ® ); T2 – sheep manure + sand (1:1); T3 – sheep manur e + sand (2:1); T4 – sheep manure + sand (3:1); T5 – sheep manure + soil (1:1) ; T6 – sheep manure + soil (2:1); T7 – sheep manure + soil (3:1); T8 – sheep manure + sand + soil (1:1:1); T9 – sheep manure + sand + soil (2:1:1); T10 – sheep m anure + sand + soil (3:1:1). Emergence indicators were: per centage, speed index and average time of emergence. Re- garding the development characteristics of seedling s were analyzed: leaf number, seedling height, root length, shoot dry matter and root dry matter. Whereas the i ndicators of emergence and development, it can be i nferred that substrates T3 [EO + A (2:1)], T4 [EO + A (3:1) ], T6 [EO + S (2:1)], T7 [EO + S (3:1)] and T10 [EO + A + S (3:1:1)] provided similar results to those observ ed in the production of lettuce seedlings with the commercial substrate, thus providing the formation of vigorous seedlings more sustainable for the initial stage o f cultivation of this vegetable.

The crop demand by nitrogen varies from one crop to other as well as the amount and applica- tion time, and this nutrient can be lost by leachin g, volatilization and erosion. The objective of thi s study was to evaluate doses, sources and times of nitrogen appli cation in rice of high lands cropped in no till sys tem. The work was conducted in Selvíria, State of Mato Gross o do Sul, Brazil, in a soil originally under Cerrad o vegeta- tion. A randomized blocks design, with the treatmen ts disposed in a factorial scheme 5x3x2 was used. T he treatments were constituted by five nitrogen doses (0, 50, 100, 150 and 200 kg ha -1 ), three nitrogen sources (urea; ammonium sulfonitrate plus nitrification inh itor and ammonium sulfate) and two application time s (at sowing or at flower bud differentiation), with four repetitions. The sources of nitrogen, as well as t he applica- tion times had similar effects for most of evaluati ons. The N doses influenced linearly or with quadra tic adjust- ment the plant height, N leaf content and grains yi eld, in the two growing seasons. The chlorophyll co ntent and the number of ears m -2 were affected only, in the first year. The highest yield in the growing season of 2007/08 was obtained with the dose of 149 kg ha -1 of N. In 2008/09 growing season the increase of N doses provided increment in the grains rice yield, until the maxim um dose evaluated (200 kg ha -1 of N).

The soil management system can modify the natural d istribution of the soil attributes and, con- sequently, the variability of the soil aggregation and organic matter content. Thus, the aim of this w ork was to evaluate the aggregate stability and organic matter content spatial distribution on a Haplic Cambisol under sugar cane cultivation in the Southern Amazonas Sta te, Brazil. A 70 x 70 m square mesh, with regular 1 0 me- ters intervals, was designed over the cultivation a rea, resulting in 64 sample points. Soil blocks wit h preserved structure were collected at 0.0-0.2 m depth in orde r to analyze the aggregate stability and organic ma tter con- tent. The data were submitted to the descriptive an d geostatistical analysis. The soil attributes pres ented a spa- tial dependence structure and the greater range was observed for the mean weighted diameter and aggreg ate class <1.00 mm. Also, there is a spatial relation a mong the mean geometric diameter, mean weighted dia meter and aggregate classes (> 2.00 and 2.00-1.00 mm).