Determination of Evapotranspiration and Crop Coefficient of Cactus Pear (Opuntia ficus-indica Mill.) with an Energy Balance Technique

A micrometeorological approach based on surface renewal technique was adopted to estimate evapotranspiration fluxes and crop coefficient data from an irrigated cactus pear (Opuntia ficus-indica Mill.) orchard under Mediterranean climatic conditions. High-frequency temperature readings were taken above the canopy top in order to get surface renewal sensible heat flux values (HSR). These values were compared against eddy covariance sensible heat fluxes (HEC) for calibration. Latent heat flux (or evapotranspiration, ET) was obtained as the residual of the energy balance equation using HSR. In field measurements of biophysical crop features, physiological characteristic and soil hydraulic components were integrated with the analysis of the surface energy fluxes. Microlysimeters were used to compute evaporation rates, allowing the separation of transpiration from ET data. During the irrigation season, evapotranspiration from the cactus pear orchard was 330 mm of water producing 16,210 kg of dry matter ha-1 for a biomass water productivity: WPb = kg biomass m-2 per kg H2O m-2 = 6.6 710-3. The water use efficiency (WUE) was 204 kg H2O kg-1 dry matter. The low value of WPb, relative to other CAM plants, suggests an opportunity to improve the use of irrigation water

Determination of Evapotranspiration and Annual Biomass Productivity of a Cactus Pear [Opuntia ficus-indica L. (Mill.)] Orchard in a Semiarid Environment

A micrometeorological approach based on the surface energy balance was adopted to estimate evapotranspiration fluxes and crop coefficient data from an irrigated cactus pear [Opuntia ficus-indica L. (Mill.)] orchard under Mediterranean climatic conditions. Highfrequency temperature readings were taken above the canopy top to get sensible heat flux values (HSR) using the surface renewal technique. These values were compared against eddy covariance sensible heat fluxes (HEC) for calibration. Latent heat flux (or evapotranspiration, ET) was obtained by solving the daily energy balance equation. Measurements of soil hydraulic components were integrated with the analysis of the surface energy fluxes and crop development in terms of phenology and aboveground biomass accumulation. Microlysimeters were used to compute evaporation rates, allowing the separation of daily transpiration from ET data. Ecophysiological measurements were carried to estimate dry weight accumulation and partitioning. Cactus pear evapotranspired a total of approximately 286 and 252 mm of water during the two monitored growing seasons, respectively. Average daily values of crop (ETc) and reference (ET0) evapotranspiration were in the order of 2.5 and 5.0 mm, respectively, with a corresponding value of the mean crop coefficient of approximately 0.40. The annual dry mass fixed per single tree was 38.8 1.3 kg, with a total production of 12.9 t ha 121, which is comparable to many C3 and C4 plants and resulted in a water use efficiency (WUE) of 4.6 and 4.4 gDMkgH2O 121 in 2009 and 2010, respectively. The stem area index (SAI) was 3.5

CO2 fluxes of Opuntia ficus-indica Mill. trees in relation to water status

Gas exchange pattern in O. ficus-indica(OFI), refers to the Crassulacean Acid Metabolism (CAM); trees have nocturnal stomata opening, so net CO2 uptake and water loss occur during the cooler part ofthe 24-hour cycle. Succulent cladodes skip severe periods of drought through their water storer tissue (parenchyma). To study carbon fluxes in stress and no stress conditions, an experiment was carried out on 3-year-old irrigated and non-irrigated OFI potted trees; whole tree gas exchange was measured continuously with a balloon system made up by a portable Infrared Gas Analyzer. Continuous measurements(nighttime) during the summer season were useful to assess differences in carbon uptake under stress and no stress conditions. There was a gradual increment (5 μmol m2 s-1in June, 7 μmol m2 s-1 in July and 8.8 μmol m2 s-1 in August) in terms of CO2 uptake in irrigated trees from June to August 2010. The uptake was lower in stressed trees than in irrigated ones in each measurements date. Measurements carried out on non-irrigated trees showed carbon gain even 60 days after irrigation was stopped, with less than 2% of soil water content, far below the wilting point. Considering an average of 6.9 μmol CO2 m2 s-1, for well watered trees, from June to August, and a stem area index (SAI) of 2, a daily amount of 21.8 kg ha-1 d-1 of CO2 was accumulated in irrigated trees in that period, corresponding to a carbon assimilation of 0.54 T ha-1

Pluractionality in Hittite: A new look at the suffix -ške/a-

Hittite features three derivational suffixes, i.e., -ške/a-, -šša-, and -anna/i-, that attach to verbs and are commonly described as expressing a number of imperfective-like functions. So far, the distribution and use of these suffixes has defied a satisfactory explanation. Whereas some scholars argue that they operate within the domain of lexical aspect, others view them as associated with the encoding of grammatical imperfective aspect. In this paper, we focus on the interpretation of -ške/a- and argue that a better understanding of the nature of this suffix can be achieved if one frames its description within the typology of pluractional constructions. As we show, the range of polyfunctionality of -ške/a- fully complies with the cross-linguistic behavior of pluractional markers. We also provide a tentative diachronic scenario that accounts for the rise of such polyfunctionality out of the original semantic core of the suffix

Characterization and development of different methods to extend shelf life of fresh cut fruit. Case study: novel controlled release system by layer-by-layer assembly

The research project aimed at the investigation of different methods for the storage of fresh-cut fruit. This case study relates to the proposal of an innovative controlled release system to improve the shelf life of ready-to-eat fruit. The methods applied during three research years included the application of active molecules from natural substances, some widely used in commerce and other tested for the first time; first analyzed in vitro and then applied in vivo. The under consideration methods concerned dipping, coating and the layer-by-layer assembly. The analysis carried out on the fruit have monitored pomological traits performances (soluble solids content, titratable acidity, pH, color, flesh firmness), the chemical profile (polyphenoloxidase, carotenoids) and microbial growth

Quality changes during postharvest life in white fleshed peach (Prunus Persica L. Batsch) fruits: Preliminary observations

Sicilian white flesh peach fruits ecotypes are characterized by a persistent aroma and excellent flavor that is highly appreciated by consumers. Nevertheless, they reach only regional markets, because of fruit sensitivity to decay and the poor information about their postharvest physiology and shelf-life. In this trial, we studied quality changes during postharvest life of non-melting white-flesh peach ecotypes \u2018Tudia\u2019, \u2018Bella di Bivona\u2019 and the cultivar \u2018Daniela\u2019. Fruits were collected at commercial ripening: a first group was submitted to analytical evaluations and another one was stored (2\ub0C, 90% RH) for 32 days. During this storage period, fruits were submitted to four shelf-life periods at ambient temperature (22\ub0C) for 6 days and analyzed every 3th and 6th day. In the period of shelf-life, during storage of fruit at 2\ub0C, we ascertained that Bella di Bivona and Daniela have a shelf-life of 12-14 days while \u2018Tudia\u2019 could reach up to 25-32 days. Flesh firmness and chilling injuries trends, during shelf-life, allowed to discover \u2018Tudia\u2019 as the variety which presents the best performance after storage at low temperatures for long periods