Bernardo Murillo-Amador

FIELD EVALUATION OF THE RELATIONSHIP BETWEEN CHLOROPHYLL CONTENT IN BASIL LEAVES AND A PORTABLE CHLOROPHYLL METER (SPAD-502) READINGS

A hand-held SPAD-502 chlorophyll meter provides rapid and nondestructive measures of chlorophyll content. Integrating this meter into basil production can reduce costs and may improve basil quality. This study determined the relationship between SPAD-502 and the leaf chlorophyll (total, a, b). Over 500 leaf samples were collected from a field study conducted in 2006. Comparisons between chlorophyll contents and meter readings showed that SPAD meter readings were positively correlated to actual chlorophyll content. Regression analysis SPAD readings should be corrected by leaf area. Findings suggest that SPAD meter readings can be used as a tool to improve Basil quality and for assessing the relative chlorophyll content during the growing season.

Response to salinity of three grain legumes for potential cultivation in arid areas

Abstract The purpose of this study was to examine the uptake and distribution of ions in three grain legume species for potential use in arid zones. Tepary bean (Phaseolus acutifolius A. Gray), cowpea (Vigna unguiculata L. Walp.), and wild bean “frijolillo” (Phaseolus filiformis Bent) were grown during a period of 14 d in a nutrient solution salinized with 80 mmol L−1 NaCl. Plant height, leaf number, and leaf area of the saline treated plants were all low because of salinity. The dry weight (DW) of the roots, stems, and leaves of cowpea and “frijolillo” was significantly lower when the plants were subjected to the saline treatment, while the DW of the stems and leaves of the tepary bean plants treated with NaCl was close to that of the control plants (0 mmol L−1 NaCl). Root DW was significantly higher under salinity conditions only in tepary bean. The net uptake rate (NUR) and net transport rate (NTR) of Ca2+, Mg2+, and K+ in cowpea and “frijolillo” shoots were lower in the saline treated plants than in the control (0 mmol L−1 NaCl), while tepary bean subjected to the salinity treatment displayed higher cation net uptake rate and transport. The NTR / NUR ratio of Na+ in tepary bean, “frijolillo,” and cowpea treated with NaCl were 0.07, 0.70 and 0.72, respectively, indicating that Na+ transport to the shoots was in the following order: cowpea > “frijolillo” > tepary bean. Na+ distribution to roots, stems, and petioles was higher than the DW distribution to the same organs of the saline-treated plants only for tepary bean, while the Na+ distribution was lower than the DW distribution to leaves. These facts indicate that Na+ ion easily move to the leaves in cowpea, while in tepary bean and “frijolillo,” Na+ mobility is restricted in order to prevent Na+ accumulation in leaves, and is achieved through the higher capacity of the stem and petiole to hold Na+. In the cowpea and “frijolillo” plants treated with NaCl, the uptake and transport of Ca2+ and Mg2+ were significantly lower, while in the tepary bean plants these rates were not affected by the saline treatment that exerted a negligible adverse effect on plant growth. The higher Ca2+ and Mg2+ uptake in tepary bean could be caused either by the higher Ca2+ and Mg2+ absorption efficiency or by the higher Ca2+ and Mg2+ uptake and transport required to neutralize excess Cl− in the cells.

Effects of plant growth promoting bacteria and mycorrhizal on Capsicum annuum L. var. aviculare ([Dierbach] D'Arcy and Eshbaugh) germination under stressing abiotic conditions.

Capsicum annuum var. aviculare to Tarahumara and Papago Indians and farmers of Sonora desert is a promising biological and commercial value as a natural resource from arid and semiarid coastal zones. Traditionally, apply synthetic fertilizers to compensate for soil nitrogen deficiency. However, indiscriminate use of these fertilizers might increase salinity. The inoculation by plant growth promoting bacteria (PGPB) and arbuscular mycorrhizal fungi (AMF) represents an alternative as potential bio fertilizer resources for salty areas. Seeds ecotypes from four areas of Sonora desert (Mazocahui, Baviacora, Arizpe, La Tortuga), in order to inoculate them with one species of PGPB and AMF. Two germination tests were carried out to study the effect of salinity, temperature regime (night/day) and inoculation with PGPB and AMF growth factors measured on germination (percentage and rate), plant height, root length, and produced biomass (fresh and dry matter). The results indicated that from four studied ecotypes, Mazocahui was the most outstanding of all, showing the highest germination under saline and non-saline conditions. However, the PGPB and AMF influenced the others variables evaluated. This study is the first step to obtain an ideal ecotype of C. a. var. aviculare, which grows in the northwest of México and promoting this type of microorganisms as an efficient and reliable biological product. Studies of the association of PGPB and AMF with the C. a. var. aviculare-Mazocahui ecotype are recommended to determine the extent to which these observations can be reproduced under field conditions.

Preliminary compositional nutrient diagnosis norms for cowpea (Vigna unguiculata (L.) Walp.) grown on desert calcareous soil

This study calculated the compositional nutrient diagnosis (CND) norms of cowpea (Vigna unguiculata (L.) Walp.), as well as identified significant nutrient interactions of this crop growing in an irrigated calcareous desert soil. Three genotypes were distributed in rows in a 2-ha field. The soil showed high heterogeneity in its chemical properties. For statistical analysis, 86 foliar composite samples from healthy plants were used. Preliminary CND norms were developed using a cumulative variance ratio function and the χ2 distribution function. Means and standard deviations of row-centered log ratios VX of five nutrients (N, P, K, Ca, and Mg) and a filling value R, which included all nutrients not chemically analyzed. Preliminary CND norms are: VN*=0.174±0.095, VP*=−2.172±0.234, VK*=−0.007±0.267, VCa*=−0.022±0.146, VMg*=−1.710±0.132, and VR5*=3.728±0.084. These CND norms are associated with dry bean yields higher than 1.88 t ha−1, and are associated with the following foliar concentrations: 26.2 g N kg−1, 2.5 g P kg−1, 22.9 g K kg−1, 21.6 g Ca kg−1, and 4 g Mg kg−1. Cowpea plants growing in desert calcareous soils took up lower amounts of N, P, and K than those considered as optimum in a previous report. Six interactions were strongly indicated for cowpea through principal component analyses: positive for Ca–Mg, and negative for N–Ca, N–Mg, Ca–P, Mg–P, and K–P. Furthermore, two interactions were identified using simple correlations, negative N–P and positive K–Ca.

Mineral content and biochemical variables of Aloe vera L. under salt stress.

Despite the proven economic importance of Aloe vera, studies of saline stress and its effects on the biochemistry and mineral content in tissues of this plant are scarce. The objective of this study was to grow Aloe under NaCl stress of 0, 30, 60, 90 and 120 mM and compare: (1) proline, total protein, and enzyme phosphoenolpyruvate carboxylase (PEP-case) in chlorenchyma and parenchyma tissues, and (2) ion content (Na, K, Ca, Mg, Cl, Fe, P. N, Zn, B, Mn, and Cu) in roots, stems, leaves and sprouts. Proline and PEP-case increased as salinity increased in both parenchyma and chlorenchyma, while total protein increased in parenchyma and decreased in chlorenchyma, although at similar salt concentrations total protein was always higher in chlorenchyma. As salinity increased Na and Cl ions increased in roots, stems, leaves, while K decreased only significantly in sprouts. Salinity increases typically caused mineral content in tissue to decrease, or not change significantly. In roots, as salinity increased Mg decreased, while all other minerals failed to show a specific trend. In stems, the mineral concentrations that changed were Fe and P which increased with salinity while Cu decreased. In leaves, Mg, Mn, N, and B decreased with salinity, while Cu increased. In sprouts, the minerals that decreased with increasing salinity were Mg, Mn, and Cu. Zinc did not exhibit a trend in any of the tissues. The increase in protein, proline and PEP-case activity, as well as the absorption and accumulation of cations under moderate NaCl stress caused osmotic adjustment which kept the plant healthy. These results suggest that Aloe may be a viable crop for soil irrigated with hard water or affected by salinity at least at concentrations used in the present study.

Effect of Pseudomonas putida on growth and anthocyanin pigment in two poinsettia (Euphorbia pulcherrima) cultivars.

Pseudomonas putida is plant growth promoting rhizobacteria (PGPR) that have the capacity to improve growth in plants. The purpose of this study was to determine growth and anthocyanin pigmentation of the bracts in two poinsettia Euphorbia pulcherrima cultivars (Prestige and Sonora Marble) using three strains of P. putida, as well as a mixture of the three (MIX). Comparison with the control group indicated for the most part that Prestige grew better than the Sonora Marble cultivars with the PGPR strains. Prestige with the MIX strain grew better compared to control for the number of cyathia (83 versus 70.4), volume of roots (45 versus 35 cm3), number of leaves (78 versus 58), and area of leaf (1,788 versus 1,331 cm2), except for the number of flowers (8.8 versus 11.6). To the naked eye, coloration of plants appeared identical in color compared to the control group. For all plants with P. putida strains, there was less anthocyanin pigment, but biomass was always greater with PGPR strains. Nevertheless, to the naked eye, the coloration of the plants appeared identical in color compared to the control group. This is the first study reporting the positive effects of P. putida rhizobacteria treatments on growth of poinsettia cultivars.

Changing environmental conditions and applying organic fertilizers in Origanum vulgare L.

Any improvement in agricultural systems that results in higher production should also reduce negative environmental impacts and enhance sustainability. The aim of this research was to investigate the effect of two different production systems, one open-field and the other shade-enclosure with four bocashi doses, in order to find the best environmental option in terms of yield, physiological and morphometric characteristics in one oregano (Origanum vulgare L.) cultivar. In this study a completely randomized block design was used with four replications and evaluated for photosynthetic and transpiration rate, stomatal conductance, chlorophyll, leaf area and temperature, aerial and roots fresh and dry biomass, fresh and dry yield. The results showed that oregano adapted best to the shade-enclosure with increase yield of fresh and dry leaf weight of 165% and 118%, respectively, when compared to open-field. Also, higher doses of bocashi improved yield in both environments but more so in shade-enclosure. Soil moisture retention was higher in shade-enclosure which was reflected in physiological variables for soil matric potential, transpiration, stomatal conductivity, photosynthesis being significantly higher in shade-enclosure compared to open-field, thus improving yield. It seems that oregano plants can be grown and perform better under shade-enclosure than open-field and bocashi is a suitable organic fertilizer.

Nutrients Use Efficiency in Legume Crops to Climatic Changes

Legumes, with the ability of 88% of the species examined to date to form nodules with rhizobia and fix nitrogen, are second only to the Gramineae in their importance to humans. Legume species are going to play a very important role in relationship to the nutrient use and efficiency in agriculture under climate changes resulting from human activity. Climate change associated with increased human caused CO2 pollution will affect weather patterns, resulting in increased global temperatures and rainfall, more extreme events, and regional changes in annual mean temperatures and precipitation. These changes will impact all inhabitants in the world, including through food production. The effects may be direct, for example via increased photosynthesis or indirect via changes in soil microclimate affecting rates of mineralization of nutrients. In this sense, climate change may have beneficial as well as detrimental consequences for agriculture and crop nutrient use efficiency. Some research indicates that warmer temperatures lengthen growing seasons and increased carbon dioxide in the air results in higher yields. Together these would increase nutrient demand from some crops and potentially may lead to either increased nutrient use efficiency or reduced efficiency for example via inability to supply adequate P resulting in reduced N fixation. While changes, will likely vary significantly by region a warming climate and decreasing soil moisture can also result in production patterns shifting northward and an increasing need for irrigation. These shifts in production system are also likely to lead to changes in nutrient use efficiency by legumes.

Baseline study of morphometric traits of wild Capsicum annuum growing near two biosphere reserves in the Peninsula of Baja California for future conservation management

BackgroundDespite the ecological and socioeconomic importance of wild Capsicum annuum L., few investigations have been carried out to study basic characteristics. The peninsula of Baja California has a unique characteristic that it provides a high degree of isolation for the development of unique highly diverse endemic populations. The objective of this study was to evaluate for the first time the growth type, associated vegetation, morphometric traits in plants, in fruits and mineral content of roots, stems and leaves of three wild populations of Capsicum in Baja California, Mexico, near biosphere reserves.ResultsThe results showed that the majority of plants of wild Capsicum annuum have a shrub growth type and were associated with communities consisting of 43 species of 20 families the most representative being Fabaceae, Cactaceae and Euphorbiaceae. Significant differences between populations were found in plant height, main stem diameter, beginning of canopy, leaf area, leaf average and maximum width, stems and roots dry weights. Coverage, leaf length and dry weight did not show differences. Potassium, sodium and zinc showed significant differences between populations in their roots, stems and leaves, while magnesium and manganese showed significant differences only in roots and stems, iron in stems and leaves, calcium in roots and leaves and phosphorus did not show differences. Average fruit weight, length, 100 fruits dry weight, 100 fruits pulp dry weight and pulp/seeds ratio showed significant differences between populations, while fruit number, average fruit fresh weight, peduncle length, fruit width, seeds per fruit and seed dry weight, did not show differences.ConclusionsWe concluded that this study of traits of wild Capsicum, provides useful information of morphometric variation between wild populations that will be of value for future decision processes involved in the management and preservation of germplasm and genetic resources.

Perfil de ácidos grasos en leche de vacas Chinampas (Bos taurus) alimentadas con forraje fresco de matorral sarcocaulescente o heno de alfalfa

Resumen es: El objetivo del estudio fue determinar la concentracion de acidos grasos (AG) en la leche de vacas Chinampas, con enfasis en los acidos grasos conjugados...