Luis Guillermo Hernández-Montiel

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.

Caracterización de levaduras Debaryomyces hansenii para el control biológico de la podredumbre azul del limón mexicano Characterization of yeast Debaryomyces hansenii for the biological control of blue mold decay of Mexican lemon

Twelve yeast Debaryomyces hansenii strains were characterized for their ability to inhibit in vitro growth of Penicillium italicum, production of lytic enzymes (β-1.3-glucanase, chitinase and protease) and postharvest biological control of blue mold decay (caused by P. italicum) on Mexican lemon fruits. The D. hansenii strains inhibited in vitro the growth of P. italicum in different pHs (4.2, 4.6 y 5.0), effect related to killer toxins. The enzyme activity (of β-1.3-glucanase, chitinase and protease) was detected on Yeast Nitrogen Base (YNB) medium inoculated with cell wall fragments of P. italicum, the range enzymatic activity of all strains was between 9 and 13 days after inoculated culture medium. All D. hansenii strains significantly reduced blue mold on Mexican lemon during fifteen days of storage at 13 °C, but the LL1 strain was distinctly more effective under these conditions. These results showed that D. hansenii is an alternative for biological control of blue mold decay of Mexican lemon fruits.

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.

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.

Efficiency of two inoculation methods of Pseudomonas putida on growth and yield of tomato plants

The objective of this study was to determine the efficiency of applying microcapsules and liquid inoculation of three Pseudomonas putida strains on growth and yield of tomato plants in greenhouse where the results showed differences between both treatments. Rhizobacterial strains FA-8, FA-56, and FA-60 of P. putida, were assessed individually and combined to determine their capacity to produce indoleacetic acid (IAA). The three strains demonstrated the capacity to produce IAA in vitro, of which FA-56 stood out with 23.02 μg mL-1 in the microcapsule treatment with significant increases in plant height, stem diameter, radical volume, dry biomass, fruit yield, and rhizobacterial population (CFU). These responses could have been associated to the intrinsic capacity of this strain to produce a greater amount of IAA, hormone related to promoting plant growth. The use of plant growth-promoting rhizobacteria (PGPR) as biofertilizers by means of microcapsules could be an alternative in agricultural management and sustainable production of tomato. Immobilization of P. putida rhizobacteria by alginate microcapsules confers protection and gradual release, improving adhesion, permanency, and colonization of cells on the roots, promoting a better effect as PGPR and productivity in tomato plants.

Effect of Pseudomonas putida and inorganic fertilizer on growth and productivity of habanero pepper (Capsicum Chinense Jacq.) in greenhouse

ABSTRACT The habanero pepper is widely used in a variety of commercial food products. The increase in the cultivation area of the habanero pepper has increased the use of agricultural inputs, mainly inorganic fertilizers, which have high economic costs and cause negative effects to the soil and water. In recent years, the use of beneficial soil microorganisms has been studied as an alternative to inorganic fertilizers. In the present study, the effect of three strains of Pseudomonas putida on the growth and productivity of King Pakal hybrid habanero pepper with limited inorganic fertilizer in a greenhouse. It was found that a reduction of inorganic fertilizer application of 25% with P. putida rhizobacteria strains increased or maintained growth and productivity of King Pakal hybrid habanero pepper. Before these rhizobacteria can be used in the field, results will first need to be confirmed under more natural conditions.

Effect by Plant Growth Promoting Bacteria ( Azospirillum halopraeferens and Klebsiella pneumoniae ) on Lipid Value in Seed of the Halophyte Salicornia bigelovii Torr.

Halophytes species appears on great scale as an alternative for the essential fatty acid production in human nutrition, for that reason, the fatty acid composition receives special importance. Salicornia bigelovii is a halophyte that developed in arid and coastal zones like Sonora State and the peninsula of South Baja California, Mexico. Salicornia could be an alternate species in the edible oil production. The similar fixation of N2 by bacteria associated with roots of Salicornia bigelovii and halophyte are an important nitrogen source available in coastal ecosystems. The inoculation of Klebsiellapneumoniae and Azospirillumhalopraeferens was evaluated during the vegetative development of Salicornia bigelovii under field conditions in two ecotypes (Cerro Prieto = CP and Santa Rosa = SR), having affected positively variable as weight, yields of production and biochemical characteristics and contained total of ashes, protein and total lipids in seed produced. Our results suggest that both ecotypes of S. bigelovii, under the conditions field used, can be improved with the application of K. pneumoniae and A. halopraeferens, showing a potential utility for agricultural producers of coastal semi-arid zones.