Effect of Canopy Gaps on Growth and Water Use Efficiency of Seedling of Vulnerable Species, Hopea sangal Korth

Aims: Hopea sangal Korth. is listed as vulnerable species and recently its remnant habitat was rediscovered in the degraded forest near the springs area in East Java. In the forest, the regeneration of the seedling and saplings understory is affected by the heterogeneity in environmental factors especially various light levels due to the canopy gaps. H. sangal is considered a shade-tolerant species, hence the establishment of the seedling in its natural habitat occurs under the closed canopy. This study aimed to understand the Water Use Efficiency (WUE) and Relative Growth Rate (RGR) of Hopea sangal Korth seedling grown in two different levels of tree canopy shades. Study Design: This research was using a completely randomized design, with 9 replications. Place and Duration of Study: This study was conducted in the Purwodadi Botanic Garden, East Java, between March � July. Methodology: We used seedling of H. sangal collected from the field in Pasuruan which were planted in plastic pots and acclimatized to obtain seedling of a similar size. The microclimate was measured weekly using solarimetri and sling psychrometer at 08.00; 10:00; 12:00; 14:00 and 16:00. RGR was measured by harvesting the seedling and whole plant WUE was measured using the gravimetric method. Results: We observed the light level during the periodic opening of the canopy gap was significantly different at a specific time (8-12 am), with the highest light intensity at 10.00 of 333.57 祄ol photon m-2s-1. The canopy shades differences did not affect the WUE of seedling (P = 0.333), meanwhile, there was a significant difference in the seedling RGR (P = 0.025). The seedling that were grown under a higher gap and received higher light intensity periodically during a day had higher RGR than those under a closed canopy. The WUE has a positive relationship with the RGR of seedling (R2 = 0.5; P < 0.05). Conclusions: This study suggested that the H. sangal is one of the shade-tolerant species capable of responding to gap-opening sunlight. The study also showed RGR of the seedling positively correlated with the WUE of plants, indicating that the seedling could use the water supply efficiently to grow rapidly.

Comparative physiological and histological investigations on resistant and susceptible pomegranate genotypes infected with Xanthomonas axonopodis pv. Punicae

Xanthomonas axonopodis pv. punicae (Xap) is a bacterial pathogen wreaking havoc in pomegranate cultivation. It causes bacterial blight disease dwindling yield and making fruit unfit for consumption. Physiological and histological investigations during host-pathogen interaction are prerequisite to assess the onset of defense mechanism in plants. Therefore, we tried to compare the pomegranate resistant (IC 318734) and highly susceptible (Ruby) genotypes challenged with Xap. The bacterial suspension containing Xap cells of 0.3 OD600 (~106 to 107CFU mL?1) was used for challenge inoculation. Uniformly grown resistant and highly susceptible plants were selected, the surface of leaves was pricked and spray-inoculated with bacterial suspension using native strain IIHR1 (NCBI Gen Bank ID: KT 222897). Simultaneously, the control plants were also sprayed with only distilled water and observed. A total of three replications with five plants per replication were maintained and evaluated under completely randomized design. Physiological investigations were recorded using Portable photosynthesis system (LCpro+, ADC BioScientific limited, UK) for one cycle of disease progression viz., 0, 1, 5, 10, 15 and 20 days after bacterial spray inoculation (DAI). Significant changes in gas exchange parameters were witnessed on pathogen inoculation. Higher reduction in mean percent change of photosynthetic and transpiration rate, instantaneous water use efficiency, internal CO2 content, stomatal conductance and relative water content were noticed in highly susceptible genotype than resistant one. On contrary, an increased percent mean change of intrinsic water use efficiency, carboxylation capacity and lignin was documented in resistant genotype. Relative injury caused due to bacterial infection was found high in highly susceptible genotype than resistant one. Histological investigations in highly susceptible and resistant genotype were studied on 20th day of Xap inoculation using Scanning Electron Microscopy. Highly susceptible genotype exhibited maximum deformed cells, tissues and other visible abnormalities upon Xap inoculation. Thus, this study forms a basis for effective disease management and breeding programmes in pomegranate.

Stomatal behaviour and endogenous phytohormones promotes intrinsic water use efficiency differently in cotton under drought

The coordination between phytohormones regulation, stomatal behaviour (stomatal index and opening/closing) and gas exchange are potent determinants of plant survival under drought stress. However, we found a knowledge gap in the mechanism regulating the fine-tuning of these features during drought. In order to address this we evaluated gas exchange, stomatal behaviour and endogenous phytohormones content in two cotton varieties (LRA-5166 and NBRI-67) differing in drought sensitivity during water deficit conditions. Variety specific differences were recorded in net photosynthesis rate (A), transpiration rate (E) and stomatal conductance (gs) with significantly less decrease in drought tolerant LRA-5166 than drought sensitive NBRI-67. The abscisic acid (ABA) accumulation was significantly increased in LRA-5166 while reduced in NBRI-67 under water deficit, which was accompanied by relatively less reduced 6-benzylaminopurine (6-BAP) level in LRA-5166 than NBRI-67.Thus, improved ABA/6-BAP ratio was observed in both the varieties of cotton. Critically, LRA- 5166 has reduced stomatal index, aperture size and significantly higher A and intrinsic water use efficiency (WUEi), thus higher drought tolerance than NBRI-67. Furthermore, we found that endogenous ABA predominantly maintains the stomatal behaviour and regulates its physiology either by antagonizing 6-BAP or alone to coordinate with water deficit signals. Overall, our findings describe a new insight as to how drought modulates endogenous ABA and 6-BAP homeostasis in cotton leaf and the mechanism of stomatal regulation by ABA and 6-BAP in cotton.

Atmospheric evaporative demand and water deficit on the ecophysiology of Rubber seedlings

The search for genetic materials resistant to adverse weather conditions has been a major focus in studies on species of economic interest. The objective of the present study was to assess the growth and photosynthesis of rubber seedlings clones under two conditions of atmospheric evaporative demand, characterized by fluctuations in temperature (TEMP) and vapor pressure deficit (VPD), associated to two water regimens. Hevea brasiliensis Muell. Arg (RRIM 600 and FX 3864) clones were assessed in two microclimates, at low (TEMP 21.2 ºC and VPD 0.29 Kpa) and high (TEMP 26.9 ºC and VPD 1.49 Kpa) atmospheric evaporative demand, under two water regimens: water deficit and well-watered. Water deficit 50% water availability was sufficient to reduce the net CO2 assimilation rate, leaf area and total chlorophyll of the clones studied that impacted growth in both microclimates. The effects of water deficit on growth and net carbon assimilation rate were intensified under high atmospheric evaporative demand. However, when comparing the two clones studied, RRIM 600 showed greater growth and photosynthesis without water restriction. The FX 3864 clone, despite the high CO2 assimilation values under high atmospheric demand and without water restriction, showed a reduced growth. The results of this study form an important basis for the selection of genotypes with the potential to develop in adverse climatic conditions. In this sense, the RRIM 600 genotype is recommended as a promising material that would best adapt under adverse climatic conditions.

Ecophysiology and water use efficiency of soybean cultivars under field conditions

A wide range of soybean cultivars is available on the market and understanding the physiological response and yield of these materials is fundamental to develop new management systems. Thus, the objective of the present study was to assess ecophysiological parameters and yield of soybean cultivars under field conditions. The experiment was carried out on a farm located in the municipality of Açailândia, Maranhão, Brazil. Three commercial cultivars were used (SC1, SC2 and SC3), and gas exchanges, SPAD index, Fv/Fm, photosynthesis index (PI), instantaneous water use efficiency (WUE) and intrinsic instantaneous of the use of water (iWUE) were assessed during the vegetative (V5) and reproductive (R5) stages. In addition, the biomass and production components were obtained. A randomized complete block design was used, with three cultivars and six replications. SC2 obtained the best mean for the photochemical variables. SC2 was more efficient at both development stages in WUE, but the maximum iWUE values were obtained in SC3. The SC2 cultivar obtained the best responses in the main variables analyzed, resulting in a higher yield.

Plant density on yield of Husk tomato (Physalis ixocarpa Brot.) in field and greenhouse / Densidade vegetal no rendimento de tomate Husk (Physalis ixocarpa Brot.) em campo e casa de vegetação

ABSTRACT: Physalis ixocarpa Brot. (tomatillo or Husk tomato) is one of the five major vegetables cultivated in Mexico, but its yield in the field is low. However, greenhouse crops and the enhancement in plant density can promote an increase in yield per area. The aim of this research was to evaluate: yield, water consumption and water use efficiency of variety husk tomato 'Diamante'. The experiment was conducted under field and greenhouse conditions, during the two crop cycles (autumn-winter and spring-summer), with different planting densities (1.5, 2 and 3 plants m-2), in complete random blocks and three replications. The yield was influenced by the planting density and environments. In both environments, the planting density, with 3 plants m-2 increased yield 32 %, and 25% in water use efficiency (WUE). In greenhouse increased 32% yield m-2 and the WUE it was 18.1 kg m-3 while in the field was 16.4 kg m-3. Crop cycle spring-summer produced differences of 27% in plant length and 15% in stem diameter, probably due to the temperature that was 4 ºC higher with respect to autumn-winter.

RESUMO: Physalis ixocarpa Brot. (tomatillo ou tomate de cáscara) é um dos cinco principais vegetais cultivados no México, mas seu rendimento no campo é baixo. No entanto, as culturas em estufa e o aumento da densidade das plantas podem promover um aumento no rendimento por área. O objetivo desta pesquisa foi avaliar: rendimento, consumo de água e eficiência no uso da água do tomate de casca de variedade 'Diamante'. O experimento foi conduzido em condições de campo e casa de vegetação, durante os dois ciclos de cultivo (outono-inverno e primavera-verão), com diferentes densidades de plantio (1,5, 2 e 3 plantas m-2), em blocos aleatórios completos e três replicações. O rendimento foi influenciado pela densidade e pelos ambientes de plantio. Nos dois ambientes, a densidade de plantio, com três plantas m-2, aumentou a produtividade em 32% e em 25% na eficiência no uso da água (WUE). Em casa de vegetação aumentou 32% do rendimento m-2 e o WUE foi de 18,1 kg m-3, enquanto no campo foi de 16,4 kg m-3. O ciclo da safra primavera-verão produziu diferenças de 27% no comprimento das plantas e 15% no diâmetro do caule, provavelmente devido à temperatura 4 ºC maior em relação ao outono-inverno.

Gas Exchange, Root Morphology and Nutrients in Maize Plants Inoculated with Azospirillum brasilense Cultivated Under Two Water Conditions

HIGHLIGHTS Azospirillum brasilense stimulates root growth in maize under water deficit. Maize inoculated with A. brasilense shows greater photosynthesis under drought conditions. Under water deficit, maize plants inoculated with A. brasilense showed greater water use efficiency (WUE).

Abstract The objective of this study was to evaluate the gas exchange, root morphology and nutrient concentration in maize plants inoculated with A. brasilense under two water conditions. The experiments were carried out in a greenhouse, one under irrigation and the other under water deficit. The treatments consisted of four A. brasilense inoculants (control (without inoculation), Az1 (CMS 7 + 26), Az2 (CMS 11 + 26) and Az3 (CMS 26 +42). At the V6 plant stage, water stress was imposed on maize plants for 15 days. The phytotechnical characteristics, gas exchange, root morphology, root dry matter and macronutrient analysis were evaluated after 15 days of water deficit imposition. The water deficit caused a reduction in the development of maize plants. The presence of A. brasilense Az1 under the same condition yielded higher photosynthesis, carboxylation efficiency, water use efficiency, and greater soil exploration with increased length, surface area and root volume of plants. Inoculation by A. brasilense increased root system volume by an average of 40 and 47% under irrigation and water deficit, respectively, when compared to non-inoculated plants. The inoculant Az1 attenuated the deleterious effects caused by drought and yielded the best growth of the root system, resulting in the tolerance of maize plants to water deficit.

Suitable soil moisture contents for water use efficiency and saponins accumulation in Panax notoginseng / 中草药·英文版

Objective: The moisture content in the soil directly affects the yield and quality of Panax notoginseng, especially at the age of three years old. However, the suitable moisture for the growth of P. notoginseng is unknown. In this study, the effects of different soil moisture on the growth of P. notoginseng were studied. Methods: Four different water treatments (0.45 field capacity (FC), 0.60 FC, 0.70 FC, and 0.85 FC) were set up in Shilin County, Yunnan Province, China. The water consumption and daily dynamic of water consumption were determined daily (from April 21 to October 18, 2012), and the daily dynamic of water consumption under different weather conditions (sunny and rainy) was determined. The transpiration coefficient and water use efficiency were calculated through dry matter accumulation and total water consumption. Accumulation of saponins of roots of P. notoginseng were analyzed by HPLC after treated, and the soil moisture content suitable for the growth of P. notoginseng was estimated by regression fitting of the active ingredient accumulation and the soil moisture content. Results: The water consumption of 0.85 FC, 0.70 FC, 0.60 FC and 0.45 FC were 2.89, 3.68, 3.37 and 2.73 kg/plant per day, respectively. The water consumption of P. notoginseng from June to August was greater than other months. The daily dynamic of water consumption on sunny days and sunny days after rain showed a “double peak” feature, and it showed a “single peak” feature on rainy days. The water uses efficiency (WUE) of 0.85 FC, 0.70 FC, 0.60 FC and 0.45 FC were 2.51, 3.32, 4.59, 3.39 gDW/kg H

Precision tools for irrigation management of tomato seedlings / Ferramentas de precisão para manejo de irrigação de mudas de tomate

Seedling production is important to vegetable productions, however, irrigation planning for seedling production is usually inefficient due to the lack of information about water consumption by the seedlings, which decreases the quality of the seedlings. The objective of this work was to evaluate the use of hydrogel in the substrate and determine the appropriate irrigation management for the production of tomato seedlings (Solanum lycopersicom), using an automated irrigation system. The experiment was conducted in a protected environment at the Federal University of Viçosa, Brazil. Tomato seedlings were grown in polyethylene trays on substrates with, and without hydrogel. The seedlings were irrigated using an automated micro sprinkler system. Irrigation treatments were chosen considering different crop evapotranspiration (ETc) and reference evapotranspiration (ETo), and the use of timer. The height, root length, stem base diameter, root and shoot dry weights, seedlings were evaluated. The use of the hydrogel for the production of tomato seedlings resulted in seedlings with higher final heights, larger stem base diameter, greater shoot dry weight, larger crown area projection, and greater shoot relative growth rate.

A produção de mudas é um ponto crítico do sistema de produção de hortaliças. Devido a informações sobre o consumo de água pelas mudas, o planejamento da irrigação se torna ineficiente, fato que provoca perdas na qualidade das mudas. O objetivo do experimento foi testar o uso de hidrogel no substrato e determinar o manejo de irrigação adequado através de ferramentas de automatização do sistema de irrigação. O experimento foi conduzido em ambiente protegido na Universidade Federal de Viçosa. Foram produzidas mudas de tomate (Solanum lycopersicom) em bandejas de polietileno, preenchidas com substrato com e sem a presença de hidrogel. As mudas foram irrigadas com sistema de microaspersão, acionado a partir de um sistema automatizado. Os tratamentos de manejo de irrigação foram através da evapotranspiração da cultura (ETc), timer, 0.50 ETo e 1,00 ETo. Foram avaliados componentes de qualidade das mudas como altura, comprimento de raiz, diâmetro de colo, massa seca de raiz e parte aérea. O uso do hidrogel foi um diferencial para produção de mudas de tomate mais precoces, com maior altura final, maior diâmetro de colo, maior acúmulo de massa seca de parte aérea, maior área de projeção da copa e maior a taxa de crescimento relativo de parte aérea. Na presença do hidrogel o manejo 0.50 ETo favoreceu maiores plantas, com colo mais fino e menor massa seca de parte aérea.

Effects of deficit irrigation and kaolin application on vegetative growth and fruit traits of two early ripening apple cultivars

BACKGROUND: Drought is one of the main serious problems for agriculture production which its intensity is increasing in many parts of the world, hence, improving water use efficiency is a main goal for sustainable agriculture. RESULTS: Growth indices including relative shoot length growth (SL), relative stem diameter increase (SD) and relative trunk cross sectional area growth (TCSA) measured at the start and end of the season decreased by reducing the irrigation level. Chlorophyll index (CI) was decreased at 70% crop evapotranspiration, however water use efficiency (WUE), leaf and fruit total phenolic content (TPC), and fruit anthocyanin content (AC) were among the traits that showed increment by water deficit stress in both cultivars. Shafi-Abadi cultivar showed to be more sensitive to the water stress than 'Golab' Kaolin treatment improved SL, SD and CI traits, but this increase was statistically significant only for SD at 5% level. Kaolin had no significant effect on yield and water use efficiency (WUE), however, it had negative effect on yield efficiency (YE). Kaolin treatments also significantly increased fruit and leaf TPC (P< 0.01) but had no effect on leaf and fruit total antioxidant activity (AA), as well as fruit anthocyanin content (AC) and soluble proteins (SP). CONCLUSIONS: Irrigation at 85% ETc showed better results than 100% and 70% ETc levels for yield attributes. It seems that the more pronounced effect of kaolin on vegetative traits but not on the fruits, might be attributed to the early ripening and harvest time of the examined cultivars.

Physiological response and productivity of safflower lines under water deficit and rehydration

ABSTRACT Water deficit is one of the major stresses affecting plant growth and productivity worldwide. Plants induce various morphological, physiological, biochemical and molecular changes to adapt to the changing environment. Safflower (Carthamus tinctorius L.), a potential oil producer, is highly adaptable to various environmental conditions, such as lack of rainfall and temperatures. The objective of this work was to study the physiological and production characteristics of six safflower lines in response to water deficit followed by rehydration. The experiment was conducted in a protected environment and consisted of 30 days of water deficit followed by 18 days of rehydration. A differential response in terms of photosynthetic pigments, electrolyte leakage, water potential, relative water content, grain yield, oil content, oil yield and water use efficiency was observed in the six lines under water stress. Lines IMA 04, IMA 10, IMA 14 showed physiological characteristics of drought tolerance, with IMA 14 and IMA 16 being the most productive after water deficit. IMA 02 and IMA 21 lines displayed intermediate characteristics of drought tolerance. It was concluded that the lines responded differently to water deficit stress, showing considerable genetic variation and influence to the environment.

The role of supplemental irrigation to crop water use under rainwater harvesting / O papel da irrigação suplementar na redução do uso da água através da captação de águas pluviais

Sorghum is an important food and dominant multi-purpose cereal crop in Sudan. Its production influenced by plant available soil water content at planting and growing season rainfall. Series of field experiments were carried-out to study the sorghum water use potentiality using different water harvesting techniques (WHT) and supplemental irrigation (SI). Soil moisture content (SMC), grain yield and water use efficiency (WUE) of sorghum were calculated during the years of 2012 and 2013. The results showed that the WHT and SI affected the SMC, growth and productivity parameters of sorghum. The results were also indicated that, the tied-ridging with SI (T1w) produced the highest values of SMC, sorghum productivity and WUE (10.59%, 3850 kg ha-1, and 0.71 kg m-3 in season 2012, respectively. Whereas in season 2013 the values were 11%, 4760 kg ha-1and 0.86 kg m-3 with the same arrangement mentioned above. Conclusively, the WUE could be promoted by implementing WHT as water stewardship. Nevertheless SI should consider as pivot factor that compensate the shortage in the rainwater.

O sorgo é um alimento importante e uma cultura de cereais multi-propósito dominante no Sudão. Sua produção é influenciada pelo teor de água disponível no solo da planta na plantação e na precipitação da estação de crescimento. Foram realizadas séries de experimentos de campo para estudar a potencialidade do uso da água do sorgo usando diferentes técnicas de colheita de água (WHT - water harvesting techniques) e irrigação suplementar (SI - supplemental irrigation). O teor de umidade do solo (SMC - Soil moisture content), o rendimento de grãos e a eficiência do uso da água (WUE - water use efficiency) de sorgo foram calculados nos anos de 2012 e 2013. Os resultados mostraram que o WHT e SI afetaram os parâmetros SMC, crescimento e produtividade do sorgo. Os resultados também foram indicados que o empate com SI (T1w) produziu os maiores valores de SMC, produtividade de sorgo e WUE (10,59%, 3850 kg ha-1 e 0,71 kg m-3 na temporada 2012, respectivamente). Enquanto que na temporada 2013, os valores foram de 11%, 4760 kg ha-1 e 0,86 kg m-3 com o mesmo arranjo mencionado acima. Conclusivamente, a WUE poderia ser promovida pela implementação de WHT como gerenciamento de água. No entanto, a SI deve considerar como fator de pivô que compense a escassez na água da chuva.

Establishment of Mimosa biuncifera (Fabaceae) inoculated with arbuscular mycorrhizal fungi in greenhouse and field drought conditions / Establecimiento de Mimosa biuncifera (Fabaceae) inoculada con hongos micorrízicos arbusculares en invernadero y campo, en condiciones de sequía

AbstractMexico is dominated by arid or semi-arid ecosystems, predominantly characterized as xeric shrublands. These areas are frequently deteriorated due to agriculture or over-grazing by livestock (sheep and goats). The vegetation type mainly consists of thorny plant species, and among these, the dominant one in overgrazed areas is catclaw (Mimosa biuncifera). This is a nurse plant that facilitates establishment of other vegetation and promotes plant succession. Catclaw plants form a mutualistic association with arbuscular mycorrhizal fungi (AMF), which improves uptake of nutrients and water. The objective of this study was to determine the effect of inoculating catclaw plants with native AMF and starting their growth under a low water availability treatment in a greenhouse, and later transplanting them to field conditions of drought and deterioration. Field plants were evaluated according to their survivorship and growth. The seeds of catclaw plants and soil with AMF spores were collected in the Mezquital Valley of Hidalgo State, in Central Mexico. Seedlings were grown in individual pots in a greenhouse. The experimental design consisted of two levels of pot irrigation, wet (W) and dry (D), as well as the presence (M+) or absence (M-) of AMF inoculum, with 20 replicates for each treatment. The following plant parameters were recorded every week: height, number of leaves and pinnae, and mean diameter of coverage. After 20 weeks in the greenhouse, determination was made of fresh and dry biomass, relative growth rate (RGR), root/shoot ratio, real evapotranspiration (RET), water-use efficiency (WUE), and percentage of mycorrhizal colonization. The remaining plants growing under the dry treatment (M+ and M-) were then transplanted to a semi-arid locality in the Mezquital Valley. During one year, monthly records were kept of their height, number of leaves, mean diameter of coverage and survival. Results showed that compared to greenhouse plants under other treatments, those under the wet mycorrhizal (WM+) treatment were taller, had more pinnae, and were characterized by greater coverage, faster RGR, and greater fresh and dry biomass. Moreover, inoculated plants (WM+ and DM+) showed higher WUE than those uninoculated (WM- and DM-, respectively). After one year in field conditions, there was a higher survival rate for previously inoculated versus uninoculated plants. Hence, mycorrhization of M. biuncifera with native AMF inoculum increased plant efficiency in biomass production, thus favoring establishment and survival in field conditions. We concluded that inoculation of catclaw plants is recommendable for revegetation programs in deteriorated semi-arid zones. Rev. Biol. Trop. 64 (2): 791-803. Epub 2016 June 01.

ResumenMás de la mitad del territorio mexicano está dominado por ecosistemas áridos y semiáridos. El principal tipo de vegetación de estos ambientes son matorrales xerófilos y normalmente están deteriorados por agricultura y sobrepastoreo de ovejas y cabras inducido por la actividad humana. Las plantas espinosas dominan en estas zonas, como el gatuño (Mimosa biuncifera Benth., Fabaceae), que es una planta nodriza que promueve la sucesión vegetal. Las plantas de gatuño forman junto con hongos micorrizógenos arbusculares (HMA), una asociación mutualista llamada micorriza arbuscular que mejora la captación vegetal de nutrimentos y agua. El objetivo de este trabajo fue determinar el efecto de la inoculación con HMA nativos en plantas de gatuño, para evaluar su crecimiento y establecimiento bajo un tratamiento de baja disponibilidad hídrica, tanto en condiciones de invernadero como de campo. Para esto, se recolectaron semillas de Mimosa biuncifera y suelo con esporas de HMA en el Valle del Mezquital, estado de Hidalgo, en el Centro de México. Las plántulas fueron cultivadas en macetas individuales en condiciones de invernadero bajo un diseño experimental que consistió en dos tratamientos de riego de las macetas, húmedo (W) y seco (D), y dos tratamientos de inoculación: con y sin inóculo de HMA (M+, M-). Cada tratamiento tuvo 20 repeticiones. Semanalmente se registró altura, diámetro medio de la cobertura y número de hojas y pinnas de las plantas. Después de 20 semanas, se determinaron biomasa húmeda y seca, tasa relativa de crecimiento (TRC), proporción raíz vástago, evapotranspiración real, eficiencia en el uso del agua (WUE) y porcentaje de colonización micorrícica. Posteriormente, los individuos del tratamiento seco (M+ y M-) fueron trasplantados a una localidad semiárida en el Valle del Mezquital, donde la altura, número de hojas y supervivencia fueron registrados mensualmente durante un año. Los resultados muestran que las plantas en el tratamiento húmedo y micorrizado (WM+) tuvieron una mayor altura, cobertura vegetal, biomasa húmeda y seca, TRC y más pinnas que las plantas de los otros tratamientos; también los tratamientos micorrizados (WM+ y DM+) tuvieron mayor WUE que la plantas sin inóculo (M-). En condiciones de campo, después de un año, la supervivencia de las plantas M+ fue mayor que en los testigos. Se concluyó que la micorrización de M. biuncifera con inóculo nativo incrementa su eficiencia en la producción de biomasa y favorece el establecimiento y supervivencia en condiciones de campo. Finalmente, se recomienda la inoculación de plantas de gatuño con HMA en programas de revegetación de zonas semiáridas deterioradas.

Onion yield under agroecological farming system using distinct irrigation depths and soil covers / Produtividade de cebola em sistema de cultivo agroecológico sob distintas lâminas de irrigação e coberturas do solo

ABSTRACT: The present study was carried out in order to evaluate the effects of irrigation depths applied through drip and presence/absence of soil cover in onion yield, under agroecological farming. The experiment was conducted in Seropédica, RJ, Brazil, from May to September 2012. The experimental design was a randomized complete block with split-plot design with 10 treatments and 7 replications, characterized by the presence (+S) and absence (-S) of soil cover and five irrigation depths according to percentages of the crop evapotranspiration (ETc): 0, 22, 45, 75 and 100% (0, 155, 220.6, 320.5 and 372,7mm in +S condition and 0, 145.5, 207.6, 285, 351,4mm in -S condition). The irrigation influenced by second-order polynomial regression the total yield of bulbs, percentage distribution of bulbs in diameter classes and water use efficiency (WUE) in the -S condition, and in the linear regression the WUE in +S condition. The soil cover promoted an increase on the total bulb yield, WUE and the percentage of bulbs classified in classes of greater diameter.

RESUMO: O presente estudo teve como objetivo avaliar os efeitos de lâminas de irrigação, aplicadas via gotejamento, e do uso de cobertura morta na produção de cebola em cultivo agroecológico. O experimento foi conduzido em Seropédica, RJ, no período de Maio a Setembro de 2012. O delineamento experimental adotado foi em blocos completos casualizados com parcelas subdivididas, com 10 tratamentos e 7 repetições, caracterizados pela presença (CC) e ausência (SC) de cobertura do solo e por cinco lâminas de irrigação, relativas às porcentagens da evapotranspiração da cultura (ETc): 0, 22, 45, 75 e 100% (0; 155; 220,6; 320,5 e 372,7mm na condição SC e 0; 145,5; 207,6; 285 e 351,4mm na condição CC). A irrigação influenciou, por meio da regressão polinomial de segunda ordem, as variáveis produtividade total de bulbos, distribuição do percentual de bulbos em classes de diâmetro e eficiência do uso da água (EUA) na condição SC e, na regressão linear a EUA, na condição CC. A cobertura morta promoveu um incremento na produtividade total de bulbos, na eficiência do uso da água e no percentual de bulbos enquadrados nas classes de maior diâmetro.

Effects of different water management options and fertilizer supply on photosynthesis, fluorescence parameters and water use efficiency of Prunella vulgaris seedlings

BACKGROUND: Prunella vulgaris L. is a medical plant cultivated in sloping, sun-shaded areas in China. Recently, owing to air-environmental stress, especially drought stress strongly inhibits plant growth and development, the appropriate fertilizer supply can alleviate these effects. However, these is little information about their effects on P. vulgaris growing in arid and semi-arid areas with limited water and fertilizer supply. RESULTS: In this study, water stress decreased the photosynthetic pigment contents, inhibited photosynthetic efficiency, induced photodamage in photosystem 2 (PS2), and decreased leaf instantaneous WUE (WUEi). The decreased net photosynthetic rate (Pn) under medium drought stress compared with the control might result from stomatal limitations. However, fertilizer supply improved photosynthetic capacity by increasing the photosynthetic pigment contents and enhancing photosynthetic efficiency under water deficit. Moreover, medium fertilization also increased WUEi under the two water conditions, but fertilizer supply did little to alleviate the PS2 photodamage caused by drought stress. Hence, drought stress was the primary limitation in the photosynthetic process of P. vulgaris seedlings, while the photosynthetic characteristics of the seedlings exhibited positive responses to fertilizer supply. CONCLUSIONS: Appropriate fertilizer supply is recommended to improve photosynthetic efficiency, enhance WUEi and alleviate photodamage under drought stress.

Produção de cultivares de batata em diferentes sistemas de irrigação / Production of potato cultivars in different irrigation systems

Objetivou-se avaliar diferentes cultivares e sistemas de irrigação na produção de batata na região nordeste de Mato Grosso do Sul. O experimento foi realizado entre maio e setembro de 2011 e conduzido em esquema de parcelas subdivididas, tendo nas parcelas dois sistemas de irrigação (Gotejamento e Tripa) e nas subparcelas três cultivares de batata (Asterix, Atlantic e CLL), no delineamento em blocos casualizados, com quatro repetições. O manejo da irrigação foi realizado por meio da obtenção da evapotranspiração e de dados do solo e cultura. Foram avaliadas as seguintes características: comprimento, largura e espessura dos tubérculos, número de tubérculos por planta, produtividade comercial e eficiência do uso da água. A irrigação total necessária no sistema de irrigação por tripa superou o sistema por gotejamento devido ao maior coeficiente de localização e menor eficiência de aplicação da água. A cultivar Asterix apresentou maiores fatores biométricos de tubérculo, produtividade e eficiência de uso da água pela batata. Os sistemas de irrigação por gotejamento e tripa não afetaram a produção de batata, entretanto, o sistema por gotejamento deve ser preferido devido apresentar maior eficiência de aplicação da irrigação e de utilização da água pela cultura.

This study aimed to evaluate different cultivate and irrigation system in production of potato in the northeast of Mato Grosso do Sul State. The experience was made between May and September of 2011 and mounted in a complete randomized block, with four replications, in a split-plot design. The plots a two irrigation systems (drip irrigation and tubes of perforates plastic) and three cultivate of potato (Asterix, Atlantic and CLL). The irrigation management was by evapotranspiration and data of soil and culture. The following characteristics had been studied: length, width and thickness of tubercles, tubercle per plant number, commercial yield and water use efficiency. The necessary total irrigation in the system of irrigation for tubes of perforates plastic was greater that the drip irrigation because of the greater localized coefficient and minor irrigation efficiency. To Asterix cultivate, it presented greaters biometric factors, yield and water use efficiency. The irrigation systems had not affected the production of potato, however, the drip irrigation must be preferred because it presents a greater irrigation efficiency and water use efficiency for the culture.

Water and nutrient productivity in melon crop by fertigation under subsurface drip irrigation and mulching in contrasting soils / Produtividade da água e de nutrientes em melão fertirrigado por gotejamento subterrâneo sob mulching em diferentes tipos de solo

Cropping intensification and technical, economic and environmental issues require efficient application of production factors to maintain the soil productive capacity and produce good quality fruits and vegetables. The production factors, water and NPK nutrients, are the most frequent limiting factors to higher melon yields. The objective of the present study was to identify the influence of subsurface drip irrigation and mulching in a protected environment on the water and NPK nutrients productivity in melon cropped in two soil types: sandy loam and clay. The melon crop cultivated under environmental conditions with underground drip irrigation at 0.20m depth, with mulching on sandy loam soil increased water and N, P2O5 and K use efficiency.

A intensificação dos cultivos e os aspectos técnico-econômicos e ambientais requerem maior eficiência concernente à aplicação dos fatores de produção, visando à manutenção da capacidade produtiva dos solos, à obtenção de hortaliças e de frutos de boa qualidade. Dentre os fatores de produção, a água e os macronutrientes NPK são os que limitam os rendimentos do melão com maior frequência. Este trabalho teve como objetivo identificar a influência do gotejamento subterrâneo e do mulching, em ambiente protegido, na produtividade da água e dos macronutrientes NPK, num cultivo de melão em dois tipos de solo: Latossolo Vermelho Amarelo (franco-arenoso) e Argissolo Vermelho (argiloso). A cultura do melão em ambiente protegido apresentou aumento de eficiência do uso da água e dos macronutrientes NPK com a utilização de irrigação por gotejamento subterrâneo a 0,20m de profundidade, com o uso do mulching e em solo franco-arenoso.

Fluxo de biomassa e estrutura do dossel em capim-braquiária manejado, sob lâminas de irrigação e idades de crescimento / Biomass flow and canopy structure in brachiaria grass managed under irrigation depth and growth ages

Objetivou-se avaliar o fluxo de biomassa e a estrutura do dossel do capim-braquiária manejado sob cinco lâminas de irrigação (3,84; 4,39; 6,19; 8,62 e 10,46 mm dia-1) e quatro idades de crescimento, num delineamento inteiramente casualizado em arranjo de parcelas subdivididas, sendo as lâminas de irrigação, estudadas nas parcelas, e as idades de crescimento (10, 17, 24 e 31 dias), nas subparcelas, com quatro repetições. Constatou-se interação entre lâminas de irrigação x idades de crescimento para a altura do dossel. Verificou-se resposta quadrática com ponto de mínimo para a relação folha/colmo e eficiência de uso da água em função do avanço nas idades de crescimento. Constatou-se resposta linear crescente para a taxa de alongamento foliar e taxa de alongamento dos colmos com o incremento nas lâminas de irrigação. Constatou-se resposta crescente para a biomassa de forragem verde, biomassa de lâmina foliar verde, relação material vivo/material morto, densidade populacional de perfilhos e índice de área foliar com o avanço nas idades de crescimento. As idades de crescimento mais avançadas proporcionam incremento na biomassa de forragem e a irrigação favorece o fluxo de biomassa do capim-braquiária.

This research aimed to evaluate the biomass flow and canopy structure of Brachiaria decumbens under five water supply (3.84, 4.39, 6.19, 8.62 and 10.46 mm day-1). A completely randomized with split-plot design of five irrigation depth being the plots and growth ages (10, 17, 24 and 31 days), the subplots, with four replicates were adopted. It was interaction found between irrigation depth and growth ages for the canopy height. Quadratic responses were observed to the leaf/stem ratio and water use efficiency with minimum value in function to the advance in growth ages. It was observed positive linear response to the leaf elongation rate and stem elongation rate with the increase in irrigation depth. It was found positive linear responses to the green forage biomass, green leaf biomass, green material/dead material, tiller population density and leaf area index with increasing growth ages. The growth ages increment the herbage biomass and the irrigation improve favor the biomass flow of Brachiaria grass.

Drought induced changes in growth, leaf gas exchange and biomass production in Albizia lebbeck and Cassia siamea seedlings.

Diurnal trends in net photosynthesis rate (PN ), stomatal conductance (gs ), water use efficiency (WUE) and biomass were compared in six-month-old seedlings of Albizia lebbeck and Cassia siamea, under different levels of drought stress. The potted plants were subjected to four varying drought treatment by withholding watering for 7 (D1), 14 (D2) and 25 (D3) days. The fourth group (C) was watered daily and treated as unstressed (control). Species differed significantly (p<0.001) in their physiological performance under varying stress conditions. Higher PN of 11.6 ± 0.05 in control followed by 4.35 ± 0.4 in D1 and 2.83 ± 0.18 @mol m-2 s-1 in D2 was observed in A. lebbeck. A significant (p<0.001) reduction in PN was observed in C. siamea ( C 7.65 ± 0.5 @mol m-2 s-1, D1, 2.56 ± 0.33 @mol m-2 s-1 and D2, 1.4 ± 0.01 @mol m-2 s-1 ) at 9 hr. A positive correlation was seen between PN and gs (A. lebbeck, r2= 0.84; C. siamea, r2= 0.82). Higher WUE was observed in C. siamea (D2, 7.1± 0.18 @mol m-2 s-1; D3, 8.39 ± 0.11 @mol m-2 s-1) than A. lebbeck, (control, 7.58 ± 0.3 @mol m-2 s-1 and D3, 8.12 ± 0.15 @mol m-2 s-1). The chlorophyll and relative water content (RWC) was more in A. lebbeck than C. siamea. Maximum biomass was produced by A. lebbeck than C. siamea. From the study, one could conclude that A. lebbeck is better than C. siamea in adopting suitable resource management strategy and be best suited for the plantation programs in the semi-arid dry lands.

Ecophysiological responses of some maquis (Ceratonia siliqua L., Olea oleaster Hoffm. & Link, Pistacia lentiscus and Quercus coccifera L.) plant species to drought in the east Mediterranean ecosystem.

The objective was to examine the adaptation strategies of four maquis species to drought prone environments; typical of the east Mediterranean area in degraded and healthy sites in Turkey. A comparison made between sites for Pistacia lentiscus and Quercus coccifera shows higher net daily photosynthesis in the degraded site, when compared with the healthy site; but Ceratonia siliqua and Olea oleaster exhibited no difference in their photosynthetic activity in environmentally contrasting conditions. The pattern of daily transpiration shows higher values in the degraded site in the case of P. lentiscus and Q. coccifera, while no site effect was observed for C. siliqua and O. oleaster. In the case of Q. coccifera, a behavior similar to C. siliqua was observed. A comparison made between C. siliqua and O. oleaster to observe seasonal differences in daily patterns of net photosynthesis and transpiration reveals that Q. coccifera had the highest water use efficiency (slope= 2.88; r²= 0.61), followed by C. siliqua (slope= 2.74; r²= 0.7), P. lentiscus (slope= 2.56; r²= 0.52) and O. oleaster (slope= 2.40; r² = 0.78). Olea oleaster and P. lentiscus performed as a drought tolerant species, being more resistant to aridity and thus indicative of the degradation state of the site. Ceratonia siliqua and Q. coccifera were found avoiding drought by adopting first a water-spending strategy, and then a water-saving strategy.