Effect of flower orientation on the male and female traits of Myrtillocactus geometrizans (Cactaceae).

Autor: Aguilar-García SA; Departamento de Biología, Universidad Autónoma Metropolitana-Iztapalapa, Ciudad de México, México., Figueroa-Castro DM; Facultad de Ciencias Biológicas, Benemérita Universidad Autónoma de Puebla, Ciudad Universitaria, Puebla, México., Valverde PL; Departamento de Biología, Universidad Autónoma Metropolitana-Iztapalapa, Ciudad de México, México., Vite F; Departamento de Biología, Universidad Autónoma Metropolitana-Iztapalapa, Ciudad de México, México.
Jazyk: angličtina
Zdroj: Plant biology (Stuttgart, Germany) [Plant Biol (Stuttg)] 2018 May; Vol. 20 (3), pp. 531-536. Date of Electronic Publication: 2018 Mar 25.
DOI: 10.1111/plb.12713
Abstrakt: Intra-individual variation in the production and size of reproductive traits has been documented in columnar cacti, being higher in equator-facing flowers. Such variation is attributed to the high amount of PAR intercepted by stems oriented towards the equator. Most studies focused on this phenomenon have documented the existence of intra-individual variation on traits associated with the female function; however, its impact on traits associated with the male function has been neglected. We tested the hypothesis that equator-facing flowers of Myrtillocactus geometrizans exhibit higher values on traits associated with both male and female functions than flowers facing against it. Number and size of anthers and ovaries, pollen:ovule ratio and number and quality of pollen grains (diameter, germinability, viability and pollen tube length) were estimated from reproductive structures facing north and south, and compared with t-tests between orientations. Number of anthers per flower, number of pollen grains per anther and per floral bud; pollen size, viability and germinability; pollen tube length; ovary length and pollen:ovule ratio were significantly higher in reproductive structures oriented towards the south (i.e. equator). These findings suggest that intra-individual variation in floral traits of M. geometrizans might be associated with different availability of resources in branches with contrasting orientation. Our results provide new evidence of the existence of a response to an orientation-dependent extrinsic gradient. To our knowledge, this is the first study documenting the existence of intra-individual variation on pollen quality and P:O ratio in Cactaceae species.
(© 2018 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.)
Databáze: MEDLINE
Externí odkaz: