Leaf gas exchange and yield of three upland rice cultivars

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Interferência das plantas daninhas na nutrição e produtividade da cultura da berinjela cultivar 'Nápoli' com e sem tutoramento e desbrota

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Resposta da terceira soqueira da cana-de-açúcar à aplicação de nitrogênio na presença e ausência de silício

Pós-graduação em Agronomia (Ciência do Solo) - FCAV

Bactérias promotoras de crescimento e adubação nitrogenada no crescimento inicial de cana-de-açúcar proveniente de mudas pré-brotadas

The objective of this work was to evaluate the effects of the inoculation with plant growth-promoting bacteria on the formation of sugarcane pre-sprouted seedlings, originated from individual buds, and to quantify the initial growth of these seedlings in association with nitrogen application, in a low fertility soil. Two experiments were carried out: one in greenhouse conditions, with a time span of 50 days, and the other in vases under field conditions, with a time span of 180 days. In both experiments, a randomized complete block design was used with a factorial arrangement of 2x3, in the first experiment - with or without inoculation, and with three quantities of bud reserve -, and of 2x2x4, in the second one - with or without inoculation, with or without nitrogen, evaluated in four times: at 45, 90, 135, and 180 days. The inoculant had effect on the initial growth of the pre-sprouted seedlings, increasing sprouting speed and dry matter accumulation on roots and shoots, regardless of the bud reserve amount. In the second experiment, the inoculant increased the initial growth of shoots and root system up to 180 days after transplantation, increasing height, tillering, stalk diameter, dry matter production of stalks and straw, and root length, regardless of nitrogen application. The inoculant has a positive physiological effect on plant growth.

Acúmulo de massa seca na soja em resposta a aplicação foliar com silício sob condições de déficit hídrico

The foliar fertilization with silicon has promoted several actions beneficial to plants, among them is greater drought tolerance, however, for the soybean, there is little information on these benefits in this condition. Thus, the aim of this study was to evaluate the effect of silicon on leaf, the dry matter accumulation of soybean in their reproductive stages, where the crop water stress suffered during the same. The experiment was carried out at the Plant Science Unit Aquidauana University - State University of Mato Grosso do Sul. The statistical design was a randomized block split plot with four replications. The plots were represented by cultivar 5DR615, the subplots consisted of the application (with or without) silicon, whose source was used KSi. Was measured the height and identified the development stage of all plants, separating them into stem + branches, leaves + petioles, pods capsules and seed. Foliar applications of silicon increased dry matter accumulation during the reproductive stage of soybean, where the highest values occurred in the R6 stage. Under conditions of water deficit, foliar application of silicon on soybean provided normal plant development, generating greater dry mass of stem + branches, leaves + petioles, pods capsules and seeds throughout their reproductive phase, with the highest values obtained at R6 stage (35 days after R2).

Desempenho e uso eficiente da terra de modalidades de consorciação com milho e forrageiras

This study was developed with the aim of evaluating the performance and land use efficiency of different arrangements of intercropping with maize and forage. The field experiment was conducted in Tangar da Serra/MT. The experimental design was a randomized block in factorial scheme 3x2 + 1, were as three arrangements of intercropping, two species of forage and an additional treatment with maize monoculture in four replication. In maize monoculture and intercropping were evaluated: plant height and ear insertion height, plant population, weight of 100 grains, productivity, number of grain rows and number of grain per row. In forages intercropping with maize were evaluated plant population and dry matter accumulation. The arrangements with Maize + Forage sown in the line and Maize + Forage sown in two rows between rows with the species Urochloa hybrid promoted best corn yields. The modality and species affect both the productivity of maize as forages species. Grain yield of maize is higher in monoculture. The higher dry matter accumulation of Urochloa hybrid occurs in the Maize + Forage sown in one row between rows, while, for the Urochloa brizantha the arrangements studied do not affect their yields. The arrangement with best land use efficiency is Maize + Forage sown in two rows between rows for both study forage species.

Sensitivity of yellow passion fruit plants to ultraviolet-B radiation

The objective of this work was to evaluate the effects of UV-B radiation on the vegetative growth and on the gas exchange characteristics of passion fruit plants (Passiflora edulis) grown in greenhouse. The average unweighted UV-B radiation near the apex of the plants was 8 W m-2 for the UV-B treatment (high UV-B), and 0.8 W m-2 for the control plants (low UV-B). Plants were irradiated with UV-B for 7 hours per day, centered on solar noon, during 16 days. High UV-B radiation resulted in lower shoot dry matter accumulation per plant. The content of UV-B absorbing compounds and anthocyanins was increased in the plants exposed to high UV-B radiation, when compared with the control. UV-B radiation did not affect stomatal conductance or transpiration rate, but reduced photosynthesis and instantaneous water‑use efficiency, and increased intercellular CO2 concentration. The accumulation of UV-B-absorbing compounds and anthocyanins did not effectively shield plants from supplementary UV-B radiation, since the growth and photosynthetic processes were significantly reduced.

Crescimento inicial de mudas de maracujazeiro amarelo em função de doses crescentes de superfosfato simples

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Acúmulo de micronutrientes em beterraba submetida a diferentes manejos de fertirrigação e niveis de salinidade

Knowledge of the amount of nutrients accumulated in the plant provides important information that can assist in the fertilization of crops program. To study the salt effect caused by high amounts of fertilizers applied by fertigation, an experiment was conducted in a greenhouse at the FCA/UNESP, Botucatu, SP. The experiment lasted 90 days (01/11/11 to 29/01/12) constituting five levels of electrical conductivity (1.0, 3.0, 6.0, 9.0, and 12.0 dS m-1), fertigation two management (M1: traditional management, M2: management by controlling the ionic concentration of the soil solution) and two varieties of beets (Early Wonder and Itapuã) blocks with 4 repeats forming a 5x2x2 factorial. From the dry weight of shoots and roots was determined the levels of micronutrients (B, Cu, Fe, Mn, Zn mg kg-1), and by multiplying the dry matter accumulation was determined in these plant . The accumulation of micronutrients in different parts of the plant followed the order: Fe> Mn> Zn> B> Cu for the different management fertigation studied. The Cu, Fe, Mn element present responses to increased soil salinity leading to greater absorption.

Predicting Growth of Panicum maximum: An Adaptation of the CROPGRO-Perennial Forage Model

Warm-season grasses are economically important for cattle production in tropical regions and tools to aid in management and research on these forages would be highly beneficial both in research and the industry. This research was conducted to adapt the CROPGRO-Perennial Forage model to simulate growth of the tropical species guineagrass (Panicum maximum Jacq. cv. 'Tanzania') and to describe model adaptation for this species. To develop the CROPGRO parameters for this species, we began with values and relationships reported in the literature. Some parameters and relationships were calibrated by comparison with observed growth, development, dry matter accumulation, and partitioning during a 17-mo experiment with Tanzania guineagrass in Piracicaba, SP, Brazil. Compared with starting parameters for palisadegrass [Brachiaria brizantha (A. Rich.) Stapf. cv. 'Xaraes'], dormancy effects of the perennial forage model had to be minimized, partitioning to storage tissue or root decreased, and partitioning to leaf and stem increased to provide for more leaf and stem growth and less root. Parameters affecting specific leaf area and senescence of plant tissues were improved. After these changes were made to the model, biomass accumulation was better simulated, mean predicted herbage yield was 6576 kg ha(-1), averaged across 11 regrowth cycles of 35 (summer) or 63 d (winter), with a RMSE of 494 kg ha(-1) (Willmott's index of agreement d = 0.985, simulated/observed ratio = 1.014). The model also gave good predictions against an independent data set, with similar RMSE, ratio, and d. The results of the adaptation suggest that the CROPGRO model is an efficient tool to integrate physiological aspects of guineagrass and can be used to simulate growth.

Growth of the crabgrass species Digitaria ciliaris and Digitaria nuda

The aim of this research paper was to compare the growth of D. ciliaris and D. nuda crabgrass species under non-competitive conditions. To this end, two experiments were conducted, one from March - July 2010 and the other from February - June 2011. The experimental design of both trials was completely randomized making a factorial (2 seasons x 2 species crabgrass x 12 evaluation periods) with four replications. Assessments began at 15 days after sowing (DAS), and repeated weekly until 92 DAS. The variables evaluated were total dry matter (roots+leaves+stems), leaf area, leaf number and tiller. The results were submitted to analysis of variance and the absolute growth rate, relative growth rate and leaf area ratio were calculated using the means, which were adjusted regression models. The crabgrass species were significantly different in leaf area, leaf number, tiller number and dry matter per plant. D. ciliaris for all variables was statistically higher than D. nuda. Regarding the speed at which the growth of the species occurred, the absolute growth rate and relative growth rate of D. ciliaris was also greater than D. nuda. In addition, D. ciliaris also had a lower leaf area ratio indicating greater efficiency in converting light energy into carbohydrates. It can be concluded that D. ciliaris has a higher growth rate in conditions where there is no limitation of nutrients and water availability in relation to D. nuda, mainly due to D. ciliaris have greater leaf area, number of leaves and dry matter accumulation per plant.

In vitro organogenesis of Eucalyptus grandis: effects of boron and calcium

The in vitro organogenesis of woody species plays an essential role in the improvement of forest products by providing saplings with high commercial value. Furthermore, mineral nutrition plays an important role in the induction of organogenic responses. The objective of this study was to evaluate the effects of boron and calcium in the organogenesis of nodal segments from seedlings of Eucalyptus grandis growing under in vitro conditions. The concentration of boron and calcium in MS medium was modified to induce organogenic responses in 45-day-old nodal segments used as explants. After 60 days, the fresh weight, dry weight, ratio of fresh and dry weight, relative water content and relative matter content accumulated by the explants were evaluated. The concentrations of boron and calcium in the culture medium influenced the in vitro organogenic control of Eucalyptus grandis. Reduced combinations of boron and calcium induced callus formation and dry matter accumulation in the explants. A boron concentration of 100% (1.10 mg L-1) combined with 100% (119.950 mg L-1) and 200% (239.900 mg L-1) of calcium, and 200% (2.20 mg L-1) of boron combined with 100% (119.950 mg L-1) of calcium allowed the induction of well-developed buds, which can be used for the regeneration of micro-plants.

Long-distance transport of alkali metals in maturing wheat

The alkali metals cesium, rubidium, lithium and sodium were introduced together with strontium via flaps into leaf laminas or into the stem of maturing, intact winter wheat (Triticum aestivum L. cv. Arina) grown in a field. Long-distance transport of these elements and the influence of the application date and of different application positions were investigated. The phloem-immobile Sr served as a marker for the distribution of the xylem sap in the plants. Dry matter accumulation in the grains and the transpiration per shoot were not markedly affected by the treatments as compared to control plants. The phloem mobility was rather high for Cs and Rb. Li was almost immobile in the phloem (similarly to Sr). An application into the cut stem xylem below the second leaf node contributed more to the contents in the grains than an application into the flag leaf. An earlier feeding date led to a higher accumulation in the grains. The marked losses of the elements applied during maturation (most pronounced for Li) can be explained by leakage in the rain.

Long-distance transport of cobalt and nickel in maturing wheat

Cobalt, nickel and strontium were introduced via flaps into leaf laminas or into the stem of maturing, intact winter wheat (Triticum aestivum L., cv. `Arina') grown under natural conditions in a field. Long-distance transport of these elements and the influence of the application date and of different application positions were investigated. The dry-matter accumulation in the grains was not markedly affected by the treatments as compared to untreated control plants. The phloem-immobile strontium served as a marker for the distribution of the xylem sap in the plants. After foliar application, nickel accumulated more rapidly and in higher quantities in the grains than cobalt. Therefore, nickel has a slightly better phloem mobility than cobalt. Regardless of the application date, a higher percentage of the two elements was transported from the flag leaf lamina than from the second or third lamina from the top to the grains. These results indicate that the leaf position is highly relevant for the transfer of the heavy metals investigated to the ear. Introduction into the stem led to a higher accumulation of nickel and cobalt in the grains than introduction into one of the leaves. An earlier feeding date caused a higher accumulation of nickel and cobalt in the grains when introduced into the stem. In contrast, no major differences between earlier and later feeding dates were detected when the elements were introduced into the leaves. Losses of the applied elements were detected during maturation and can be explained by leakage in the rain.

The Role of Cytosolic Potassium and pH in the Growth of Barley Roots1

In an earlier paper we showed that in fully developed barley (Hordeum vulgare L.) root epidermal cells a decrease in cytosolic K+ was associated with an acidification of the cytosol (D.J. Walker, R.A. Leigh, A.J. Miller [1996] Proc Natl Acad Sci USA 93: 10510–10514). To show that these changes in cytosolic ion concentrations contributed to the decreased growth of K+-starved roots, we first measured whether similar changes occurred in cells of the growing zone. Triple-barreled ion-selective microelectrodes were used to measure cytosolic K+ activity and pH in cells 0.5 to 1.0 mm from the root tip. In plants growing from 7 to 21 d after germination under K+-replete conditions, the mean values did not change significantly, with values ranging from 80 to 84 mm for K+ and 7.3 to 7.4 for pH. However, in K+-starved plants (external [K+], 2 μm), the mean cytosolic K+ activity and pH had declined to 44 mm and 7.0, respectively, after 14 d. For whole roots, sap osmolality was always lower in K+-starved than in K+-replete plants, whereas elongation rate and dry matter accumulation were significantly decreased after 14 and 16 d of K+ starvation. The rate of protein synthesis in root tips did not change for K+-replete plants but declined significantly with age in K+-starved plants. Butyrate treatment decreased cytosolic pH and diminished the rate of protein synthesis in K+-replete roots. Procaine treatment of K+-starved roots gave an alkalinization of the cytosol and increased protein synthesis rate. These results show that changes in both cytosolic pH and K+ can be significant factors in inhibiting protein synthesis and root growth during K+ deficiency.