María Teresa Colinas-León

Morphological changes in leaves of mexican lime affected by iron chlorosis

ABSTRACT Iron (Fe) chlorosis reduces the concentration of photosynthetic pigments, photosynthates, and crop yield. The effect of Fe chlorosis on leaf composition and cell structure was evaluated in Mexican lime (Citrus aurantifolia) with different degrees of Fe chlorosis. Iron chlorosis significantly reduced concentrations of chlorophylls a, b, and a + b, and caused thickening of leaves, due to the increase in palisade and spongy parenchyma cells. The chloroplasts of the chlorotic and albino leaves showed a disorganized ultrastructure; they had an elongated shape with disarrayed thylakoids, underdeveloped grana, scarce starch granules, and hole-like folds in the thylakoid membranes. The accumulation of calcium oxalate crystals in the upper and lower sides of the epidermis, crystal length, and total crystal content increased with Fe chlorosis severity. The green leaves, in contrast, had chloroplasts with typical ultrastructure. The degree of Fe chlorosis in the leaves significantly affected the concentrations of potassium (K); Fe, manganese (Mn), Fe2+, and the phosphorus (P)/Fe and K/calcium (Ca) ratios.

Alterations induced by Avocado sunblotch viroid in the postharvest physiology and quality of avocado 'Hass' fruit

Avocado sunblotch viroid (ASBVd) is an economically important pathogen that reduces the yield and quality standards of infected avocado trees. There are no reports on the effects of the viroid in the postharvest quality of avocado fruits. The present study has focused on three phenotypic classes: asymptomatic fruits harvested from vigorous trees (AF-V), asymptomatic fruits harvested from trees of regular vigor (AF-R) and symptomatic fruits harvested from trees expressing the disease (SF-S). The water loss was similar in the three fruit classes. The abnormal firmness condition, skin color and size reduction occurred only in SF-S fruits, which did not ripe uniformly due to reduced CO2 and ethylene production. The proximal analyses showed no significant differences in the variables analyzed, except for the lipid content and dry matter, which was lower in SF-S and AF-R fruits. ASBVd affects physiology and postharvest quality of symptomatic avocado fruits. In contrast, the ripening process of AF-V and AF-R fruits was normal and their physical characteristics and nutrient input were not altered, therefore, these fruits were classified as Supreme Quality, Extra Size (221-265 g) and Premium (172-210 g) according to the NMX-FF-016-SCFI-2006 standards.

La refrigeración en húmedo y seco afecta la vida poscosecha de flores de corte de Lisianthus (Eustoma grandiflorum) ‘ABC Blue Rim’

Facultad de Ciencias Agropecuarias. Universidad Autónoma del Estado de Morelos. Avenida Universidad Núm. 1001. Cuernavaca, Morelos. C. P. 62209. Tel. 01 777 1345402. (yoyaly@hotmail.com), (vilomar.leo@gmail.com), (mjsainz63@yahoo.es). Departamento de Horticultura. Universidad Autónoma Agraria Antonio Narro. Calzada Antonio Narro 1923. Saltillo, Coahuila, C. P. 25315. Tel 01 844 2223675. (luisalonso.valdez@uaaan.mx). Departamento de Fitotecnia. Universidad Autónoma Chapingo. Carretera México-Texcoco, km 38.5. Chapingo, Estado de México. C. P. 56230. Tel 01 595 9517682. (lozcol@gmail.com). Autor para correspondencia: ijac96@yahoo.com.mx.

CAMBIOS DE CALIDAD EN POSCOSECHA DE MENTA ( Mentha x piperita L.) ALMACENADA EN REFRIGERACIÓN

The aim of this research was to evaluate the effect of low temperatures on the postharvest physiology of peppermint (Mentha x piperita L.). Its behavior while stored at two temperatures (6 and 10 °C) compared to a control at room temperature (20 ±2 °C) was studied. A completely randomized experimental design with 4 replications was used. Respiration rate (RR), ethylene production (EP), weight loss (WL), total chlorophyll (TC), carotenoids (C) and titratable acidity (TA) were determined. A hedonic evaluation was performed (external appearance, color scale, yellowing, the development of bad odors, leaf abscission and rots). Results show that the refrigeration treatments (6 and 10 °C) maintained RR and EP with values of between 2.57 and 6.65 mL CO2 .kg-1.h-1 and 0.04 and 0.27 μL C2H4 .kg-1.h-1, respectively. WL decreased by 50 % and TC and C were preserved. Cooling enabled maintaining RR and EP without significant changes. Additionally, reduced changes were observed in WL, TC, C, TA and external quality traits required for marketing peppermint. ADDITIONAL