Lanthanum (La) is considered a beneficial element, capable of inducing hormesis. Hormesis is a dose-response relationship phenomenon characterized by low-dose stimulation and high-dose inhibition. Herein we tested the effect of 0 and 10 μM La on growth and biomolecule concentrations of seedlings of four sweet bell pepper (Capsicum annuum L.) varieties, namely Sven, Sympathy, Yolo Wonder, and Zidenka. Seedling evaluations were performed 15 and 30 days after treatment applications (dat) under hydroponic greenhouse conditions. Seedling height was significantly increased by La, growing 20% taller in Yolo Wonder plants, in comparison to the control. Similarly, La significantly enhanced shoot diameter, with increases of 9 and 9.8% in measurements performed 15 and 30 dat, respectively, as compared to the control. Likewise, La-treated seedlings had a higher number of flower buds than the control. An increase in the number of leaves because of La application was observed in Yolo Wonder seedlings, both 15 and 30 dat, while leaf area was augmented in this variety only 30 dat. Nevertheless, La did not affect dry biomass accumulation. La effects on biomolecule concentration were differential over time. In all varieties, La stimulated the biosynthesis of chlorophyll a, b and total 15 dat, though 30 dat only the varieties Sympathy and Yolo Wonder showed enhanced concentrations of these molecules because of La. Total soluble sugars increased in La-treated seedlings 30 dat. Interestingly, while most varieties exposed to La showed a reduction in amino acid concentration 15 dat, the opposite trend was observed 30 dat. Importantly, in all varieties evaluated, La stimulated soluble protein concentration 30 dat. It is important to note that while chlorophyll concentrations increased in all varieties exposed to La, both 15 and 30 dat, those of soluble sugars and proteins consistently increased only 30 dat, but not 15 dat. Our results confirm that La may improve seedling quality by enhancing some growth parameters and biomolecule concentrations, depending on the genotype, and time of exposure.

La floricultura es uno de actividades agrícolas con mayor rentabilidad en México, y el país tiene la capacidad de ser potencia exportadora en este rubro. Diversas ventajas competitivas como su posición geográfica con puertos comerciales ubicados en dos océanos, su cercanía con los Estados Unidos como uno de los principales mercados, y la firma tratados de libre comercio que le permiten acceso a más de 40 mercados internacionales, pueden permitir que México ocupe la primera posición en la exportación de f lores a nivel mundial. Actualmente, el Estado de México cultiva casi 90% de todas las flores que se venden en el país, y aún existen zonas con potencial florícola que podrían mostrar un grado de desarrollo mayor. En este estudio se realizó una caracterización de la producción y comercialización de f lores de corte, en la región de Texcoco, Estado de México, y zonas aledañas, para generar información que apoye la toma de decisiones para mejorar la actividad. Se aplicaron cuestionarios tanto a floricultores de Nativitas y Tequexquinahuac como a comercializadores de Texcoco, respectivamente. De los datos obtenidos se concluye que la floricultura en la región estudiada tiene un amplio potencial de crecimiento, a través de la mejora del sistema de producción, tecnificación, manejo poscosecha y cadena de valor, para satisfacer no sólo el mercado local y nacional, sino para promover la exportación.

Se evaluaron las características físicas y químicas del tezontle de dos granulometrías (3 y 5 mm) y su uso en la producción de tulipán (Tulipa gesneriana) cv. Ille de France, tomando como referencia el sustrato comercial ProMix®. El espacio poroso total (67 y 67.9%), el agua fácilmente disponible (2.9 y 2.3%) y la de reserva (1.9 y 1.1%) en el tezontle (3 y 5 mm, respectivamente) resultaron inadecuados para el cultivo de tulipán. El pH fue alcalino en tezontle y ácido en ProMix®; la conductividad eléctrica fue superior en éste último (1.46 dS m-1), pero aún dentro del límite establecido para sustratos. El contenido de N fue bajo en ambos materiales (en tezontles 0.61% y 0.82% en ProMix®); Ca y Mg fueron mayores en el tezontle en 60 y 24.7%, respectivamente; por el contrario, en ProMix®, el K fue cerca de tres veces superior que en tezontles. No se encontró presencia de Na en los tezontles. En plantas crecidas en tezontle de 5 mm se registraron las menores concentraciones foliares de K, Ca y Mg (11.08, 0.8 y 1.55 g kg-1, respectivamente). Las concentraciones foliares de N y P no fueron diferentes entre tratamientos. Por otro lado, las concentraciones foliares de K y Ca en plantas creciendo en tezontle de 3 mm resultaron suficientes; mientras en las establecidas en ProMix® fueron excesivas, y en tezontle de 5 mm fueron deficientes. La concentración foliar de Mg fue baja en plantas establecidas en tezontle. Se concluye que el empleo de tezontle de 3 mm puede ser una alternativa para la producción de tulipán, siempre y cuando la frecuencia de riego se disminuya.

A profile of endogenous hormones and sugars in leaves and pseudobulbs of Laelia anceps subsp. anceps (Orchidaceae) plants induced and non-induced to flowering by the effect of different doses of exogenous gibberellic acid (GA3), considering the current and back growth structures (CGS and BGS), were investigated. A factorial experiment with five doses of GA3 and two growth structures was designed. Adult plants with undifferentiated vegetative buds were selected and sprayed with doses of 0, 400, 600, 800, and 1000 mg GA3 L−1. The main results showed a strong interaction between GA3 dose and growth structures, which promoted the highest kinetin (KIN) concentration in CGS. Exogenous GA3 increased endogenous GA3 in leaves and pseudobulbs induced (I-Leaf and I-PSB) and non-induced (NI-Leaf and NI-PSB) to flowering. For sugar concentration, the 400 mg L−1 GA3 dose promotes significant interaction with the CGS in NI-PSB. In general, the hormone profile revealed opposite balances of endogenous hormone concentrations for KIN, zeatin (ZEA), trans-zeatin (T-ZEA), indoleacetic acid (IAA), indole-3-butyric acid (IBA) and GA3, not only for growth structures but also for vegetative organs analyzed, depending on whether the plants were induced or not induced to flowering, with the highest concentration of endogenous hormones in pseudobulbs. Likewise, different sugar concentration balances were observed. These balances of both endogenous hormones and sugars are likely to be involved in the flowering of L. anceps.

The efficacy of plant growth regulators (PGRs) has been demonstrated in the flowering of economically significant orchid hybrids, but studies of their effects in wild species with commercial potential are scarce. The effect of three doses of gibberellic acid (GA3) and 6-benzyladenine (BA), individually or in combination, and a control without PGRs, were evaluated during three flowering periods in Laelia anceps subsp. anceps, in the temporal behavior of flowering, morpho-floral quality parameters and in potential residual effects and malformations. Significant effects were observed between the experimental periods and doses used, with a single application of PGRs in the first period reducing the days to visible flower induction (DVFI), days to anthesis (DAN) and days of flower life (DFL), mainly in the first period. There were no significant differences between doses for morpho-floral quality parameters within each period, but differences existed between experimental periods, where the life and size of the flower increased in the first period, and the number of flowers and flower stems increased significantly in the second period. The doses of 2.37 mg · L−1 BA + 100 mg · L−1 GA3 showed highest significant consistency in the reduction of DVFI, DAN and increase of DFL and flower stems in the study. There were no floral malformations, and a positive residual effect was observed in temporal variables in the second period. Most of the doses used encourage beneficial effects in the various aspects of flowering evaluated.