Gibberellic Acid Treatment Reduces the Tolerance of Field-Grown Common Bean to Leaf Removal

Abstract

I studied the influence of gibberellic acid (GA 3 ) treatment in a field population of common bean on plant tolerance to leaf removal. Individual bean seedlings were treated with a foliar application of 10 M GA 3 on day 7 and day 14 after emergence, which led to a significant increase in height in GA 3 -treated plants. Twenty-eight days after emergence, either zero, one, two, or three leaflets from each trifoliate leaf were removed from each of 20 GA 3 -treated and 20 control plants. All pods were harvested from each plant after plants became senescent 6 weeks later. Multivariate analyses revealed that leaf removal produced significant reductions in several yield components in both GA 3 -treated and control plants, although the effects were not pronounced until at least two leaflets from each trifoliate leaf (67% of the total leaf area) were removed. However, GA 3 -treated plants suffered greater reductions in total pod wall mass and total seed number than control plants after 33 and 67% leaf area removal. These results indicate that GA 3 treatment may have altered the assimilatory capacity or resource allocation pattern of treated plants in such a way as to decrease their ability to tolerate leaf removal, a negative consequence of the hormonal alteration of traits important to plant compensation for biotic stressors.

Stretching the Limits of Plasticity: Can a Plant Defend Against Both Competitors and Herbivores?

“…1 suggests that induction of shade avoidance responses can affect both plant tolerance and resistance to herbivory through resource allocation trade-offs. By simulating plastic morphological changes to neighbors and shade with gibberellic acid application, artificially elongated individuals of common bean were shown to be less tolerant of simulated herbivory than non-elongated individuals in both the laboratory and in the field (Cipollini 1997a, Cipollini andSchultz 1999). Because external resources were not limiting in these studies, this effect was thought to reflect an opportunity cost of increased allocation to nonproductive stem material, reduced leaf area, and reduced root biomass in artificially elongated individuals (or other pleiotropic effects of gibberellic acid treatment).…”

Trading direct for indirect defense? Phytochrome B inactivation in tomato attenuates direct anti‐herbivore defenses whilst enhancing volatile‐mediated attraction of predators

“…A well-known case of allocation tradeoffs, which has received much attention in plant ecology, is that associated with the distribution of resources between growth and defense (often referred to as 'the dilemma of plants' ;Herms & Mattson, 1992;Cipollini, 2004). Evidence for the occurrence of this tradeoff comes from many sources, which show that the activation of plant defenses often correlates with reduced growth rate or competitive ability (Baldwin, 1998;Redman et al, 2001;Zavala et al, 2004;Zavala & Baldwin, 2006;Cipollini, 2007;Yan et al, 2007;Ballhorn et al, 2014), whereas fast growth is commonly associated with low levels of chemical defense and increased susceptibility to herbivory and pathogen attack (Cipollini, 1997;Kurashige & Agrawal, 2005;Donaldson et al, 2006;Izaguirre et al, 2006). Under conditions of crowding and high levels of competition, shade-intolerant plant species typically down-regulate defense responses (Ballar e, 2014), which is similar to the response described for many animals (Tollrian et al, 2015).…”

Influência do ácido giberélico sobre a arquitetura de plantas de feijão no início de desenvolvimento

“…A aplicação exógena de giberelina sobre plantas pode ser uma estratégia para aumentar a altura de inserção dos legumes por promover aumento da estatura dos entrenós mais próximos ao solo (CIPOLLINI JR., 1997;LEITE et al, 2003;VICHIATO et al, 2007). Tais características não são Acta Scientiarum.…”

“…Pelo fato dos entrenós basais serem curtos associados à baixa inserção de vagens, ocorrem perdas qualitativa e quantitativa de grãos, como também limita a colheita com automotrizes (TEIXEIRA et al, 1999). A eficiência da aplicação de GA 3 pode depender do estádio de desenvolvimento, da dose, da idade ou condição biológica geral da planta (CIPOLLINI JR., 1997;GOLOVATSKAYA;KARNACHUK, 2007;YAMAGUCHI, 2008). O GA 3 não é muito solúvel em água, ácido sulfúrico ou éter, mas é solúvel em álcool, bicarbonato e acetato.…”

“…Em feijão, a sua aplicação em sementes ainda não foi descrita, apenas foi relatado que este regulador de crescimento foi essencial para que embriões imaturos destacados "in vitro" requereram giberelina para dar origem a plântulas (SKENE, 1969). Mas, existem evidências na literatura que apontam efeitos benéficos da giberelina na alteração da arquitetura das plantas (MORRIS;ARTHUR, 1985;CIPOLLINI JR., 1997;CIPOLLINI;SCHULTZ, 1999). Assim, a giberelina poderá ser empregada para incrementar a extensão dos entrenós basais das plantas de feijão e consequentemente a inserção das vagens, e possibilitar melhorias no desempenho das colhedoras automotrizes, nesta espécie, uma vez que o emprego comercial de giberelina ainda não é uma prática agronômica corrente, seja via semente ou via pulverização da parte aérea.…”