Jailson Lopes Cruz

Níveis de nitrogênio e a taxa fotossintética do mamoeiro "golden"

This research was aimed at evaluating the effect of nitrogen (N) levels on some aspects related to the photosynthetic rate in plants of papaya Cv. Golden. The plants were cultivated under greenhouse conditions on different nutritional solutions with three concentrations of N-N3- (1.0; 5.0; 8.0molm-3). The experiment was carried out under a randomized blocks experimental design, with seven repetitions. The evaluations occurred on the 61st day after the beginning of the experiment. The nitrogen deficiency reduced the total dry mass; however, the relation root:shoot was highest for these plants. The photosynthetic rate was reduced by the lesser nitrogen availability. The results observed for the stomatal conductance and the negative correlation found between the photosynthesis and the internal concentration of CO2, indicate clearly that the reduced photosynthetic rate was not due to stomatal limitation. Additionally, the reduction verified in leaf pigments, such as chlorophylls a and b and carotenoids also could have been contributed for the reduction on photosynthesis rate and growth of these plants. Transpiratory rate was higher for the plants cultivated under stress; as consequence it was observed, for these plants, minor CO2 profit for unit of transpirated water.

Influência da salinidade sobre o crescimento, absorção e distribuição de sódio, cloro e macronutrientes em plântulas de maracujazeiro-amarelo

The presence of sodium (Na) and chloride (Cl) in growth medium have leaded to crop growth due to because of negative effects of these ions such as changes in plant capacity of uptake, transport and use of essential nutrients. The objective of this work was to evaluate the influence of salinity on growth, uptake and transport of Na, Cl and macronutrients in yellow passion fruit plants. Three levels of NaCl (0, 50 and 100 m mol L-1) were tested. Experiment was finished after 50 days of growing in 2.2 dm3 pots. It was noticed that height, leaf number, leaf area and dry mass of all parts of the plant were reduced by salinity. The concentration of Na and Cl ions increased with the increasing of salinity. However, ions were retained partially in roots (Cl) and in older leaves (Na). Concentration of nitrogen (N), phosphorous (P) and calcium (Ca) were not affected by salinity. Actually, concentration of potassium (K) was reduced in all parts of the plant while sulfur (S) was reduced only in roots. Based upon the short reduction on growth characteristics, it was concluded thatyellow passion fruit crop has a moderated tolerance to saline stress.

Produção e partição de matéria seca e abertura estomática do limoeiro 'Cravo' submetido a estresse salino

This research aimed to evaluate the influence of the salinity on some physiological parameters in Rangpur lime (Citrus limonia Osbeck), which is the principal citrus rootstock in Bahia. The importance of this study is based on the possibility of using water of low quality for irrigation, which is a production constraint for citrus crop. Rangpur lime seeds were selected by size and sowed in washed sand. Three days after the germination, the seedlings were transferred to plastic pots containing nutrient solution. After ten days, the saline treatments were applied by addition of NaCl to the growth solution in each pot, reaching the final concentrations of 0, 20, 40 and 80 mM of NaCl. The completely randomized experiment had four treatments (NaCl concentration) and five replications. Forty two days after the beginning of the saline stress the experiment was concluded. The salinity decreased total dry matter production of the stem and roots. In the intermediate levels of NaCl (20 and 40 mM), neither the leaf area nor the leaf dry matter were affected; those characters were only affected in the level of 80 mM. The increase of the salinity levels caused reduction in the root:canopy ratio, in the stomatal conductance, in the transpiration and in the leaf temperature.

Efeito do nitrato e amônio sobre o crescimento e eficiência de utilização do nitrogênio em mandioca

This study was carried out to evaluate the effect of nitrogen source on dry mass accumulation and absorption, distribution and also use of nitrogen by cassava plants. Cigana Preta cultivar plants were grown in nutrient solutions set up in 11.0 L containers. Nitrogen concentration in solutions was 12 mol m-3. Treatments included five combinations of NO3-:NH4+ , that is, 12:0, 9:3, 6:6, 3:9 and 0:12 mol m-3. Aftert 90 days the dry mass was determined. The lowest total dry mass values were obtained for plants grown with just nitrate or ammonium as nitrogen source. In this sence, ammonium affected growth more than the nitric source. The concentration of free NH4+ was higher for absorption in roots, followed by leaves and storage roots. The efficiency of nitrogen absorption was higher for plants cultivated under highest proportions of NH4+. The results showed that cassava plants grow more when growth solution contains a mixture of NO3- and NH4+, especially at the proportions of 9:3 and 6:6 mol m-3.

Influência do nitrato e do amônio sobre a fotossíntese e a concentração de compostos nitrogenados em mandioca

Plantas de mandioca (Manihot esculenta Crantz) apresentam reducao no acumulo de materia seca quando cultivadas com altos niveis de amonio na solucao do solo. A razao para esse efeito do amonio ainda permanece pouco estudada. O presente trabalho foi desenvolvido visando avaliar a influencia do NO3- e do NH4+ sobre alguns aspectos relacionados a fotossintese e a concentracao de alguns compostos nitrogenados em plantas de mandioca. Para esse estudo, utilizou-se a variedade Cigana Preta, que foi cultivada em solucao nutritiva, tendo areia grossa lavada como substrato. Os tratamentos consistiram de tres proporcoes entre NO3-:NH4+, em mM (12:0, 6:6, e 0:12). Plantas cultivadas apenas com NO3- ou com NO3- + NH4+ nao apresentaram diferencas na taxa fotosssintetica. No entanto, observou-se reducao desse evento quando o NH4+ foi a unica fonte nitrogenada. O valor da condutância estomatica obtido para as plantas cultivadas apenas com NO3- foi de 0,49mol m-2s-1, enquanto que para as plantas cultivadas apenas com NH4+, o valor foi de apenas 0,16mol m-2s-1 (tres vezes menor). Nao houve diferencas significativas na concentracao foliar de amonio livre, sugerindo nao ter ocorrido efeito toxico direto do NH4+ sobre a fotossintese. A concentracao de proteinas foi maior para as plantas cultivadas apenas com NH4+. Os resultados sugerem que o menor acumulo de materia seca das plantas de mandioca cultivadas exclusivamente com NH4+ e decorrente, dentre outros fatores, do efeito desse ion sobre a atividade fotosssintetica, em virtude, principalmente, de sua acao negativa sobre a condutância estomatica.

Influência da adubação fosfatada sobre o crescimento do camapu (Physalis angulata L. )

The specie Physalis angulata L., who belongs to the Solanaceae family, has stand out as an extremely promising plant in terms of medical use, due to the production of the physalin compound. However, important aspects of its production still remain unknown. Thus the objective of this work was to assess the influence of phosphorus for the growth of these species. The experiment was performed with three doses of P (8, 16 e 64 mg kg-1 de P), in a completely randomized experimental design. Two harvests were performed: at 30 and 42 days after planting. The deficiency of P reduced the number of leaves and leaf area. The total dry matter (DM), as well as a MS from all parts of the plant, was significantly higher for plants grown under the highest levels of phosphorus. Plants grown with 8 mg P kg-1 showed no flowers or fruit; but, for the treatment which used 64 mg of P kg-1 the beginning of flowering happened before than with the plants grown with 16mg. The ratio of the leaf area and the specific leaf area were higher for plants grown under stress, while the values of the relative growth rate and the net assimilatory rate were not statistically influenced. We conclude that the deficiency of P in soil may considerably affect the growth of Physalis plants. Moreover, since the deficiency of P significantly reduced the leaf production, which is responsible for creating the physalin, it is also possible to conclude that P deficiency may, even indirectly, reduce the concentration of this important compound in the plant.

Caracterização anatômica de órgãos vegetativos do mamoeiro

Papaya (Carica papaya L.) is a plant whose economic importance and scientific studies related to its growth and its physiology have greatly increased in recent years. Unfortunately, few researches in relation to its anatomy were performed. Thus, it was aimed to characterize the anatomically papaya plants in the early stages of growth. These studies are important because they can be used, mainly, for correlations with the growth and the physiology of this plant. After collected, the anatomical cuts of fresh root, stem and leaf were manually performed and their visualization were made through a coloration process using safranine and astra blue. The root structure is hexarc and is characterized as non-axial. The anatomical structure of the stem is similar to petiole in the mature parts. Leaf blade showed an uniestratified epidermis with dorsiventral mesophyll and anomocytic stomata were observed in the leaf abaxial surface.

Elevated CO2 reduces whole transpiration and substantially improves root production of cassava grown under water deficit

ABSTRACT We evaluated the possibility of elevated CO2 concentration ([CO2]) to reduce the negative effect of drought on growth and physiological parameters of cassava (Manihot esculenta Crantz). Plants were grown with 390 ppm or 750 ppm of CO2, under well-watered or under water deficit conditions. The study was conducted in a climate-controlled greenhouse using 14 L pots, for 100 days. For any value of fraction of transpirable soil water (FTSW) the carbon assimilation was always higher for plants grown under elevated [CO2]. Still, elevated [CO2] reduced the negative effect of drought on transpiration, water use efficiency, all growth measures and harvest index. Elevated [CO2] increased the dry matter of tuber roots (DMTR) of well-watered plants by 17.4%. The DMTR of plants grown under water deficit were 124.4 g and 58.9 g, respectively, for plants under elevated and ambient CO2, an increase of 112%. Thus, the CO2 effect was relatively stronger to the production of tuberous roots when cassava were subjected to water-deficit. Our results suggest that cassava tuber production might be resilient to changes in precipitation that will accompany higher atmospheric CO2 and reinforce cassava as a specie that can significantly contribute to mitigate hunger in a changing climate environment.

Características fisiológicas, produção total de raízes e de parte aérea em acessos de Manihot esculenta em condições de déficit hídrico (Physiological characteristics, total root and shoot production in accessions of Manihot esculenta under water ...)

Na regiao Nordeste a cultura da mandioca destaca-se como alternativa de uso agronomico e de subsistencia para a maioria dos agricultores rurais familiares. No entanto pesquisas relacionadas ao desenvolvimento de cultivares recomendaveis para sistemas produtivos dependentes de chuva sao escassas. Genotipos mais produtivos em termos de raizes e parte aerea sob condicao de seca podem ser indicados para programas de melhoramento voltados para obtencao de materiais para alimentacao humana e animal. Neste estudo, objetivou-se a identificacao, em campo, de acessos com maior capacidade de producao total de raizes e de parte aerea nas condicoes irrigada e de deficit hidrico em 49 acessos de mandioca, e identificar quais variaveis fisiologicas estao relacionadas a maior producao. A produtividade total de raizes (PTR, t/ha), foi calculada pela soma de raizes comerciais e nao comerciais, e a produtividade de parte aerea (PPA, t/ha) pela massa total de ramos e folhas, da parcela como um todo. Foram determinadas as variaveis progressao do diâmetro de caule, de diâmetro da copa, de altura da planta, da taxa relativa de expansao foliar, do indice de area foliar, do conteudo relativo de clorofila total e da eficiencia fotoquimica dos fotossistemas II. O acesso Formosa foi o mais produtivo em termos PTR tanto na condicao de irrigacao quanto de deficiencia hidrica, enquanto BGM541 foi superior quanto a PPA em ambas condicoes. Considerando a soma de PTR e PPA, o acesso Formosa se manteve como o mais produtivo. As variaveis fisiologicas avaliadas apresentaram baixa correlacao com PTR e PPA. ABSTRACT In the Northeastern region of Brazil, cassava plants stand out as an alternative to agronomical use and livelihood for most rural family farmers. Research related to the development of recommended cultivars for rain-dependent production systems are scarce. This study aimed to identify accessions with a higher total root and shoot production capacity in irrigated and water stress field conditions between 49 cassava accessions, and identify which physiological variables are related to higher production. Total Root Production (TRP, t/ha) was calculated as the sum of fresh commercial and non-commercial roots of each plot, and Shoot Production (SP, t/ha) as the sum of fresh stems and leaves. They were determined the progression of the variables crown and stem diameters, plant height, relative rate of leaf expansion, relative content of total chlorophyll, potential quantum efficiency of photosystem II, and leaf area index. The Formosa accession was the most productive in terms of TRP in the two conditions, while BGM541 accession was most productive in SP. Considering the sum of TRP and SP, the accession Formosa remained as the most productive. The physiological parameters showed low correlation with TRP and SP. Key-words: Cassava, water deficit, productivity