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The effects were examined of plantresponse signaling compounds, salicylic acid (SA) and methyl jasmonate (MeJA), on resistance to pill-bugs (Armadillidium vulgare) attack in lettuce plants. Foliar SA and MeJA applications were made at weekly intervals from the emergence of the plant until one week before harvesting. SA and MeJA induced detectable levels of hydrogen peroxide (H 2 O 2 ) at least during 5 days post-application in these plants throughout their cultivation. On the whole, SA and MeJA in the concentrations and application scheme evaluated in this research did not significantly influence the dry and fresh weight matter of plants, or the chlorophyll and nitrate contents. In addition, both signal elicitors significantly diminished lettuce mortality due to pill-bugs, which was positively correlated with phenolics and flavonoids contents. Our results suggest that SA and MeJA, especially in low concentrations, should be further evaluated in lettuce production and priming resistance.

. Cultivation was performed directly in irrigated furrows without fertilizers. The same soil type was used for both cropping systems. Number of leaves, plant height, stem diameter, length of seeds, panicle length, biomass and grain yield, grain area, percentage of popped and sprouted grain, and chemical composition were compared. The variables under greenhouse cultivation yielded superior results were grain yield (26.5%), biomass (61.2%), plant height (87.4%), stem diameter (24.3%), number of leaves (2.4%), panicle length (18.4%), percentage of popped grain (2%) and sprouted grain (7%) than field cultivation. Open field cultivation improved protein, fat and ash (9.0%, 17.6% and 43.1%, respectively), and grain size (22.5%) than greenhouse production. Thus, it may be concluded that greenhouse cultivation of A. hypochondriacus crop provides for higher yields, but inferior chemical composition values compared to the open field cultivation system.

Measuring deficiencies in the nutrition of crops is important because it allow growers to take proper action on time so as to get better development of plants. Several methods have been proposed in the measurement of nitrogen. One of those methods is image processing using color spaces. In this study, five levels of deficiency of nitrogen were induced for the evaluation in tomato seedlings. Color images were taken with a digital camera. These images were processed in Visual C++ making segmentation of the images, and for its analysis they were converted from red, green, blue (RGB) to improved hue, luminance and saturation (IHLS) color space. Luminance, saturation, hue and hue-saturation components on IHLS were proposed in the nitrogen diagnostic. Results from laboratory on the tomato leaves were taken as reference. To evaluate the data, linear regression and variance analysis with Tukey test (p<0.01) were made. Hue was the value that had better correlated laboratory values obtaining R 2 =0.86. Nitrogen estimation by this method in tomato seedlings is fast and economic and it has an advantage in relation to other proposed methods in RGB color spaces that it is less susceptible to changes of illumination.

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