Paulo Roberto de Camargo e Castro

Amadurecimento e senescência de mamão com 1-metilciclopropeno

Papaya (Carica papaya L.) fruits are highly perishable due the fast ripening after harvest. The search for techniques that extend the shelf life and reduce the post-harvest losses is desirable. In this study, papaya Sunrise Solo fruits were harvested in two ripening stages (green and ripe) and treated with the competitive ethylene antagonist 1-methycyclopropene (1-MCP) at concentrations of 0, 30, 90 or 270 nL L-1 for 12 h at 20oC followed by storage at room temperature (20oC) during eight days. Application of 1-MCP (90 or 270 nL L-1) delayed degreening decay. Green fruits treated with 1-MCP (270 nL L-1) presented higher firmness in relation to control fruits. 1-MCP did not affect the soluble solids of fruits. The respiration rate and ethylene production were lower in fruits treated with 1-MCP (90 or 270 nL L-1) in both ripening stages. 1-MCP extended the shelf life of green fruits from four to six days and the shelf life of ripe fruits from two to four days. The 1-MCP was efficient to delay the ripening of papayas extending their shelf life

Root growth of cane rattoons harvested green or burned

Este trabalho teve como objetivos comparar o crescimento de raizes de cana colhida crua, mecanizada e de cana apos a queima, colhida manualmente; avaliar a influencia do clima sobre as duas condicoes de crescimento e analisar o comportamento do crescimento de raizes de cana crua e cana queimada nos 1o e 2o anos de rebrota, atraves de curvas adaptadas. A pesquisa foi realizada no municipio de Morro Agudo, SP, de julho de 1995 a julho de 1997. A cultivar utilizada foi a SP 70-1143. Utilizou-se como indicadores de crescimento das raizes a materia seca e o perfil delas no solo. Avaliou-se a influencia das temperaturas e das umidades do ar e do solo sobre os tratamentos. Observou-se que o crescimento, no primeiro e no segundo ciclo, nao apresentou curvas que indicassem um padrao semelhante, tanto para cana crua, como para cana queimada, os fatores climatologicos, isoladamente, nao provocaram mudancas nos ciclos de crescimento de maneira que se identificasse uma tendencia geral. As raizes aparecem em maior quantidade em todas camadas do solo em cana crua do que em cana queimada, no primeiro ano e no segundo ano aparecem maiores em cana queimada.

Crescimento da parte aérea de cana crua e queimada

This work had as objectives: 1. to compare the shoot growth between green cane, mechanically harvested and burned cane, harvested manually; 2. to evaluate the influence of the weather on the two conditions of growth and 3. to analyze the growth of green cane and cane burned in the 1st and 2nd years of second ratoon cane crop, by means of adapted curves. The research was performed in Morro Agudo, SP, Brazil from July 1995 to July 1997. The cultivar was the SP 70 -1143. As growth indicators the following biometric indexes were used: number of tillers, number of leaves, dry matter of stalks, and leaves and leaf area index (LAI). For each treatment, 4 areas were used, each one being considered a replication. Polynomial regression and non-linear regression were used to adjust the data to the growth curves. The growth in the first cycle was similar for the green and the burned canes. At the beginning of the second cycle the green cane growth was greater, while at the end, the growth was greater for the burned cane. Tillering of the green cane did not present significant differences that confirm the negative influence of the straw in the ratoon cane crop. The climatological factors, separately, did not promote changes in the growth cycles, that could identify a general tendency. The differences in the development expressed on the curve of growth from the 1st to the 2nd year are due to the climatological factors, for both, the green and the burned cane.

Remoção da adstringência de frutos de caquizeiro 'Giombo' sob diferentes períodos de exposição aovapor de álcool etílico

The purpose of this research was to study the effect of exposure period to ethyl alcohol vapor on astringency removal of persimmon fruits (Diospyros kakixa0L.) cv. Giombo. Fruits were exposed to alcohol vapor for 24, 36 and 48 hours at 20°C and 95% RH. Chemical and physical characteristics of fruits were measured for ten days, at two day intervals. Soluble tannin content, flesh firmness, water loss, pH, soluble solids, titratablexa0acidity and ascorbic acid content were measured. This research showed that 24 and 36 hours were equally efficient in the astringency removal of fruits, although the analysis of other quality indices showed that fruits exposed for 24 hours exhibited better quality. The flesh firmness underwent a linear decrease in terms of time. The best period for consumption of the fruits was placed between the 4th and 8th day after the treatment. Fruits became edible at the 4th day after the treatment, when the content of soluble tannins was under 0.1%, imperceptible to taste, and the flesh firmness was kept for 8 days after the treatment.The purpose of this research was to study the effect of exposure period to ethyl alcohol vapor on astringency removal of persimmon fruits ( Diospyros kaki L.) cv. Giombo. Fruits were exposed to alcohol vapor for 24, 36 and 48 hours at 20°C and 95% RH. Chemical and physical characteristics of fruits were measured for ten days, at two day intervals. Soluble tannin content, flesh firmness, water loss, pH, soluble solids, titratable acidity and ascorbic acid content were measured. This research showed that 24 and 36 hours were equally efficient in the astringency removal of fruits, although the analysis of other quality indices showed that fruits exposed for 24 hours exhibited better quality. The flesh firmness underwent a linear decrease in terms of time. The best period for consumption of the fruits was placed between the 4 th and 8 day after the treatment. Fruits became edible at the 4 th day after the treatment, when the content of soluble tannins was under 0.1%, imperceptible to taste, and the flesh firmness was kept for 8 days after the treatment.

Reguladores vegetais e a anatomia da folha de tomate (Lycopersicon esculentum Mill.) cv. Ângela Gigante

The objective of this work was to evaluate the effect of plant growth regulators GA3 (50 mg. l-1), NAA (100 mg. l-1), CCC (1500 mg. l-1) and SADH (3000 mg. l-1)on the anatomy of tomato leafs of Lycopersicon esculentum Mill. cv. Ângela Gigante.The growth promoters increased the number of stomata per square millimeter on adaxial epiderm and decreased the number of epidermic cells on both sides of the leaves. In relation to the control, growth retardants increased the thickness of the lacunary parenchyma, more than the growth promoters.

Efeitos de giberelina e ethephon na anatomia de plantas de cana-de-açúcar

Universidade Estadual Paulista Instituto de Biociencias, Letras e Ciencias Exatas Dep. de Botânica

Responses in root growth, nitrogen metabolism and nutritional quality in Brachiaria with the use of thiamethoxam

This study investigated the effects of using increasing doses of thiamethoxam, a neonicotinoid insecticide, applied as seed treatment, on the physiological, biochemical and nutritional composition of Brachiaria brizantha cv. Piatã. We conducted two experiments with B. brizantha in a greenhouse, in the absence of insects. Biometric parameters and nutritional quality, for feed, were measured in the first experiment, and the root system and the leaf nitrate reductase activity were analyzed in the second experiment. The doses of: 0, 17.5, 35.0, 70.0 and 140.0xa0g of thiamethoxam per 100xa0kg of seeds, were applied in both experiments. The results show that the seed treatment with thiamethoxam resulted in a slight decrease in shoot development, but provided root growth, which led to an increase in the nitrate reductase activity that resulted in the higher crude protein content in the shoot. Our data indicate that thiamethoxam alters the metabolism and physiology of B. brizantha, and improving the feed quality is thus becoming a technological tool to be applied to crops.

Transpiration and stomatal resistance variations of perennial tropical crops under soil water availability conditions and water deficit

During the dry and rainy seasons, determinations of stomatal resistance and transpiration of five tropical crops were carried out: guarana (Paullinia cupana Kunth), coffee (Coffea arabica L.), cashew (Anacardium occidentale L.), guava (Psidium guajava L.) and rubber (Hevea brasiliensis Muell. - Arg.) trees. Experimental design was done at randomized complete blocks with five replications. During the dry season there was a decrease in values of stomatal resistance in the following order: guarana > coffee> cashew> guava > rubber, with values from 2.5 to 30.0 s.cm-1. During the rainy season the stomatal resistance values varied from 1.5 to 3.0 s.cm-1. The guarana and coffee crops showed higher resistance to water transpiration when compared to other crops. During the rainy season, the rubber tree continued to present lower stomatal resistance and, consequently, higher transpiration.

INFLUÊNCIA DA EMBALAGEM DE POLIETILENO NA REMOÇÃO DA ADSTRINGÊNCIA E NA QUALIDADE DE CAQUIS (Diospyrus kaki L.), CV. GIOMBO, ARMAZENADOS SOB REFRIGERAÇÃO

The purpose of this research was to verify the influence of polyethylene bags during the cold storage of persimmon fruits (Diospyros kaki L.) when astringency removal is performed and to evaluate the quality of fruits when submitted to this process. Packed Gionbo persimmons in low-density polyethylene bags and non-packed fruits were kept in a cold room at 1°C and 95-98% RH. After 30 days of storage, fruits were submitted to astringency removal process by exposition to alcohol vapor for 40 hours at 20°C and 95% RH. Chemical and physical characteristics of the fruits were measured during 6 days. The use of polyethylene bags resulted in less fresh matter loss after the deastringency process, but it did not affected the soluble tannin content, flesh firmness, soluble solids, titratable acidity and ascorbic acid content. Fruits in storage for 30 days and submitted at ethyl alcohol vapor became non-astringent 3 days after the treatment. However they showed low flesh firmness and high fresh matter.

Ação de reguladores vegetais no desenvolvimento, aspectos nutricionais, anatômicos e na produtividade do feijoeiro (Phaseolus vulgaris cv. Carioca)

Pot-grown plants of Phaseolus vulgaris cv. Carioca, under greenhouse conditions, were sprayed with 50ppm of gibberellic acid, 50ppm of naphthaleneacetic acid, 1000ppm of chlormequat, 3000ppm of daminozide, 100ppm of chlorflurenol and 50ppm of Figaron. Gibberellic acid significantly increased plant height and the number of leaves, chlorflurenol decreased these parameters. Daminozide increased K level and presented a tendency to increase N compounds increasing the level of proteic nitrogen. Chlorflurenol increased K and Ca levels, and Figaron also increased Ca content. Histological analysis of changes induced by chlorf lurenol showed an accumulation of starch grains on medullary parenchyma cells of petioles in treated dry beans. The yield of dry beans was inhibited by chlorflurenol and decreased by naphthaleneacetic acid, chlormequat and daminozide.