Variation for Root Aerenchyma Formation in Flooded and Non-Flooded Maize and Teosinte Seedlings

Abstract

Morphological and anatomical factors such as aerenchyma formation in roots and the development of adventitious roots are considered to be amongst the most important developmental characteristics affecting flooding tolerance. In this study we investigated the lengths of adventitious roots and their capacity to form aerenchyma in three-and four-week-old seedlings of two maize (Zea mays ssp. mays, Linn.) inbred accessions, B64 and Na4, and one teosinte, Z. nicaraguensis Iltis & Benz (Poaceae), with and without a flooding treatment. Three weeks after sowing and following a seven day flooding treatment, both maize and teosinte seedlings formed aerenchyma in the cortex of the adventitious roots of the first three nodes. The degree of aerenchyma formation in the three genotypes increased with a second week of flooding treatment. In drained soil, the two maize accessions failed to form aerenchyma. In Z. nicaraguensis, aerenchyma developed in roots located at the first two nodes three weeks after sowing. In the fourth week, aerenchyma developed in roots of the third node, with a subsequent increase in aerenchyma in the second node roots. In a second experiment, we investigated the capacity of aerenchyma to develop in drained soil. An additional three teosinte species and 15 maize inbred lines, among them a set of flooding-tolerant maize lines, were evaluated. Evaluations indicate that accessions of Z. luxurians (Durieu & Asch. Bird) and two maize inbreds, B55 and Mo20W, form aerenchyma when not flooded. These materials may be useful genetic resources for the development of flooding-tolerant maize accessions.

Tolerância à inundação de Cecropia pachystachya Trec. (Cecropiaceae): aspectos ecofisiológicos e morfoanatômicos

“…Além disso, as plantas apresentam modificações morfológicas e anatômicas quando submetidas ao alagamento (Armstrong et al 1994;Evans 2004). Comumente ocorre a hipertrofia de lenticelas, formação de aerênquima, enraizamento adventício e formação de raízes diageotrópicas (Pimenta et al 1996;Kolb et al 1998;Mano et al 2006), que podem facilitar tanto a difusão de oxigênio da parte aérea para as raízes, como a eliminação de produtos voláteis potencialmente tóxicos, como etanol, etileno e acetaldeído, que muitas vezes acumulam durante a hipoxia (Tsukahara & Kozlowski 1985;Joly 1991). A capacidade de produzir estas modificações morfoanatômicas pode determinar o nível de tolerância de uma determinada espécie ao alagamento (Laan et al 1991).…”

Respuesta de las plantas a estrés por inundación. Una revisión

“…El aerénquima se desarrolla mejor en raíces localizadas en el agua, arriba de la superficie del suelo que en raíces ubicadas dentro del suelo (Polthanee et al, 2008). Factores morfológicos y anatómicos como la formación de aerénquima en las raíces y el desarrollo de raí-ces adventicias son considerados como una de las principales respuestas de las plantas para sobrevivir a largos periodos de anoxia (Aschi-Smiti, 2003;Malik et al, 2003;Saqib et al, 2005;Mano et al, 2006;Suralta y Yamauchi, 2008).…”

“…La muerte selectiva de las células para formar aerénquima está asociada con el aumento de la actividad de enzimas proteolíticas (Aschi-Smiti, 2003) o con la acumulación de etileno (Colmer, 2003). Especies tolerantes a inundación del gé-nero Dendranthema presentan aerénquima lisogénico, mientras que los genotipos susceptibles carecen de este (Yin et al, 2010), indicando que este rasgo puede ser importante en la tolerancia a inundación (Mano et al, 2006).…”

Managing excess water in Canadian prairie soils: A review

“…These have been attributed to genetic variability, and as such, tolerance to excess water may be improved through genetic selection (Evans and Fausey 1999;Mano et al 2006;Zhang et al 2006). For example, a study examining inbred corn varieties found that those varieties that were able to regulate glycolysis to minimize ethanol production were more tolerant to excess water than varieties that could not regulate glycolysis (Evans and Fausey 1999).…”