14 research outputs found
Division of labour within flowers: heteranthery, a floral strategy to reconcile contrasting pollen fates
In many nectarless flowering plants, pollen serves as both the carrier of male gametes and as food for pollinators. This can generate an evolutionary conflict if the use of pollen as food by pollinators reduces the number of gametes available for cross-fertilization. Heteranthery, the production of two or more stamen types by individual flowers reduces this conflict by allowing different stamens to specialize in âpollinatingâ and âfeedingâ functions. We used experimental studies of Solanum rostratum (Solanaceae) and theoretical models to investigate this âdivision of labourâ hypothesis. Flight cage experiments with pollinating bumble bees (Bombus impatiens) demonstrated that although feeding anthers are preferentially manipulated by bees, pollinating anthers export more pollen to other flowers. Evolutionary stability analysis of a model of pollination by pollen consumers indicated that heteranthery evolves when bees consume more pollen than should optimally be exchanged for visitation services, particularly when pollinators adjust their visitation according to the amount of pollen collected
The best of both worlds? A review of delayed selfing in flowering plants
PREMISE OF STUDY: In a seminal body of theory, Lloyd showed that the fitness consequences of selfing will depend on its timing in anthesis. Selfing that occurs after opportunities for outcrossing or pollen dispersal can provide reproductive assurance when pollinators are limited and is expected to incur little cost, even when inbreeding depression is high. As a result, delayed selfing is often interpreted as a ĂąâŹĆbest-of-both-worldsĂąâŹïżœ mating system that combines the advantages of selfing and outcrossing.
METHODS: We surveyed 65 empirical studies of delayed selfing, recording floral mechanisms and examining information on inbreeding depression, autofertility, and other parameters to test the support for delayed selfing as a best-of-both-worlds strategy.
KEY RESULTS: Phylogenetic distribution of the diverse floral mechanisms suggests that some basic floral structures may predispose plant taxa to evolve delayed selfing. Delayed selfing appears to serve as a best-of-both-worlds strategy in some but not all species. While the capacity for autonomous selfing is often high, it is lower, in some cases, than in related species with earlier modes of selfing. In other delayed-selfers, low inbreeding depression and reduced investment in corollas and pollen suggest limited benefits from outcrossing.
CONCLUSIONS: Despite a growing literature on the subject, experimental evidence for delayed selfing is limited and major gaps in knowledge remain, particularly with respect to the stability of delayed selfing and the conditions that may favor transitions between delayed and earlier selfing. Finally, we suggest a potential role of delayed selfing in facilitating transitions from self-incompatibility to selfing
Soulful Knowledge: Using Indigenous Perspective to Construct New Pedagogies for Whole Learning
There is a complex interconnectedness between the mind, the body, and the soul when acquiring knowledge-how. Traditionally, we think of knowledge-how as an interplay between a cognitive processing (mind) and, often, a physical (body) processing of interaction with knowing how to do something. In fact, much of traditional education is centered around these two systems alone. Today, we are revolutionizing education where the end goal of education has changed in such a way that it is to, ultimately, enable students to thoughtfully engage in the world around themselves. Now, knowledge-how is considered a symbiotic relationship of the mind, body, and soul and giving opportunity for students to acquire such whole knowledge facilitates positive knowledge mobilization. This way of knowing where our soul and, therefore, emotion plays an integral role is, certainly, not a new concept. In fact, Aboriginal principles consider true knowledge the product of the personal and emotional connection tied to an experience. Currently, the B.C. Curriculum Redesign recognizes that âlearning is holistic, reflexive, reflective, experiential, and relationalâ (BC Ministry of Education, 2015). The ministry published First Peopleâs worldviews and perspectives as a list of principles for teachers to integrate into pedagogy. This paper delineates the ways in which pedagogy is returning to a holistic method where there is recognized value in studentsâ ability to connect with sentiment and produce soulful knowledge