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Cerium (Ce) belongs to the rare earth elements (REEs), and although it is not essential for plants, it can stimulate growth and other physiological processes. The objective of this research was to evaluate the effect of Ce on seed germination, initial seedling growth, and vegetative growth in rice (Oryza sativa L.) cv. Morelos A-98. During the germination process, the seeds were treated with Ce concentrations of 0, 4, 8, and 12 μM; after 5 d, germination percentage was recorded and after 10 d seedling growth was measured. For vegetative growth, a hydroponic system was established where 14-d-old plants without previous Ce treatment were transferred into nutrient solution. After two weeks of acclimatizing, 0, 25, 50, and 100 μM Ce were added to the nutrient solution for 28 d. Ce significantly increased germination and the initial growth variables of the seedlings. During vegetative growth, Ce increased plant height, number of tillers, root volume, and shoot fresh and dry biomass, without affecting root biomass weight. With low Ce concentrations (25 and 50 μM), the concentrations of chlorophylls and amino acids in the shoots were similar to those in the control, like amino acid concentration in the roots at a concentration of 25 μM Ce. Conversely, the concentration of total sugars increased in the shoot with the application of 25, 50, and 100 μM Ce, and in the roots with the application of 50 μM Ce. Also, Ce did not affect the concentration of macro or micronutrients in the shoots. However, in the roots, the high Ce concentration decreased the concentrations of Ca, Fe, Mn, and Zn, while the Mg concentration increased. Our results indicate that Ce, at the right concentrations, can function as a biostimulant in rice germination and growth.

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Disease is one of the main factors driving both natural and artificial selection. It is a particularly important and increasing threat to the managed honeybee colonies, which are vital in crop pollination. Artificial selection for disease-resistant honeybee genotypes has previously only been carried out at the colony-level, that is, by using queens or males reared from colonies that show resistance. However, honeybee queens mate with many males and so each colony consists of multiple patrilines that will vary in heritable traits, such as disease resistance. Here, we investigate whether response to artificial selection for a key resistance mechanism, hygienic behaviour, can be improved using multi-level selection, that is, by selecting not only among colonies as normal but also among patrilines within colonies. Highly hygienic colonies were identified (between-colony selection), and the specific patrilines within them responsible for most hygienic behaviour were determined using observation hives. Queens reared from these hygienic patrilines (within-colony selection) were identified using DNA microsatellite analysis of a wing-tip tissue sample and then mated to drones from a third highly hygienic colony. The resulting colonies headed by queens from hygienic patrilines showed approximately double the level of hygienic behaviour of colonies headed by sister queens from non-hygienic patrilines. The results show that multi-level selection can significantly improve the success of honeybee breeding programs.

In commercial micropropagation laboratories, the light source is one of the most important factors controlling plant morphogenesis and metabolism of plant cells and tissue and organ cultures. Lamp manufacturers have begun to rate lamps specifically for plant needs. The traditional light source used for in vitro propagation is fluorescent lamps (FLs). However, power consumption in FL use is expensive and produces a wide range of wavelengths (350-750 nm) unnecessary for plant development. Light-emitting diodes (LEDs) have recently emerged as an alternative for commercial micropropagation. The flexibility of matching LED wavelengths to plant photoreceptors may provide more optimal production, influencing plant morphology and chlorophyll content. Although previous reports have confirmed physiological effects of LED light quality on morphogenesis and growth of several plantlets in vitro, these study results showed that LED light is more suitable for plant morphogenesis and growth than FLs. However, the responses vary according to plant species. This chapter describes the applications and benefits of LED lamps on chlorophyll in plant micropropagation. Two study cases are exposed, Anthurium (Anthurium andreanum) and moth orchids (Phalaenopsisis sp.), both species with economic importance as ornamental plants, where LEDs have a positive effect on in vitro development and chlorophyll content.

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Resumen. Se presenta una revisión y discusión de los conceptos desarrollo sostenible y desarrollo sustentable, en el afán de aclarar su origen y dilucidar si los conceptos son o no sinónimos y si ambos son correctos y válidos. Se incluye un breve panorama de cómo se han usado ambos conceptos tanto en la literatura científi-ca, como en textos y leyes gubernamentales y de divulgación; también se describe la controversia que se ha generado por el uso no diferenciado de estos términos y las corrientes de pensamiento que los sustentan. Se concluye que, a pesar de que lingüísticamente ambos términos son correctos y sinónimos casi perfectos, representan posturas e ideologías diferentes, ya que el "desarrollo sostenible", representa un enfoque principal sobre el desarrollo y busca la manera que sea sostenido por medio del cuidado del ambiente y el "desarrollo sustentable", enfatiza el cuidado de los recursos naturales y su uso, pero mediante un modelo que proteja el ambiente como prioridad. . Palabras clave. Desarrollo, sostenible, sustentable, términos, controversiaAbstract. A brief revision regarding "sostenible" and "sustentable" development is shown, with the objective of clarify their origin, and if these concepts are synonymous or not, and whether both are correct and valid. A brief outlook about how these concepts have been used in scientific, governmental and popular literature is included, and also, the controversy generated regarding the not differentiated use between these terms is described. We conclude that, although linguistically speaking both terms are correct and are synonymous, both terms represent different ideologies, since the term "sostenible" keep focus on the "development"; and in the term "sustentable", the focus is on natural resources protection and management, but with a model that prioritise the protection of environment.