Effects of light availability and seed size on germination and initial growth of two congeneric species of Fabaceae

Abstract

Background and Aims: Environmental factors can interact with plant life history to determinate the reproductive strategies of adult plants and seedling recruitment. We expect that widely distributed tree species produce heavier seed and with greater variation in seed size than shrubs of restricted geographic distribution. We also predict that widely distributed tree species should be capable to germinate and develop under variable range of light conditions, while sun-adapted shrubs should germinate and develop better under high light intensity. We used as models two congeneric species of Fabaceae. Copaifera langsdorffii is a widely distributed arboreal species and C oblongifolia is a shrub with restricted distribution. Methods: Seeds were collected from two plant species in a Cerrado vegetation area, northern Minas Gerais, Brazil. The effects of light available on seed germination and seedling development was conducted in a germination chamber with controlled photoperiod, temperature and light intensity.Key results: The widely distributed tree (C. langsdorffii) had greater seed mass than the shrub (C. oblongifolia). Seeds of C. langsdorffii germinated faster under available high light, while the shrub C. oblongifolia seeds required less time to germinate under available low light and darkness. Under high light intensity, germination percentage of C. langsdorffii and C. oblongifolia seeds did not vary. However, seeds of the shrub showed a higher germination percentage under low light intensity and darkness. In general, seed mass showed a negative relationship with germination percentage, but this relationship varied in function of species and the availability of light. Copaifera langsdorffii seedlings had larger shoots and roots than C. oblongifolia. In contrast, the root:shoot ratio was higher in shrub than in tree species.Conclusions: Our results have important implications for understanding the patterns of distribution of two Copaifera species and explain the ability of C. oblongifolia to colonize disturbed areas.

Rapid seedling emergence of invasive Phytolacca americana is related to higher soluble sugars produced by starch metabolism and photosynthesis compared to native P. acinosa

“…Invasive plants cause serious ecological consequences and pose great threats to the economy and human health (Rands et al, 2010;Vila et al, 2011;Rai and Singh, 2020). Most invasive plants grow more rapidly than their native congeners, such as Copaifera langsdorffii versus C. oblongifolia, Spartina densiflora versus S. maritime, as well as Phytolacca americana versus P. acinosa (Fagundes et al, 2020;Infante-Izquierdo et al, 2020;Liu et al, 2022). Functional traits of plants, like specific leaf area and photosynthetic rate, have been an active point of research on the rapidity of plant growth (Feng et al, 2009;Liu et al, 2022).…”

Filtrates from cultures of endophytic fungi isolated from leaves of Copaifera oblongifolia (Fabaceae) affect germination and seedling development differently

“…Seed germination can also be affected by intrinsic attributes of the seed itself, such as mass and age. Seed mass is considered a key factor for germination and successful seedling recruitment (Fenner and Thompson, 2005;Fagundes et al, 2020). Larger seeds have a greater amount of nutritional reserves, exhibit higher germination percentages and produce more vigorous seedlings (Cordazzo, 2002;He et al, 2007).…”

“…In contrast, smaller seeds germinate more quickly and invest proportionately more resources in root development, and thus are favored in transient habitats. Therefore, seed germination is a critical stage in the life cycle of plants, being influenced by several abiotic factors such as light, temperature and humidity (Veloso et al, 2017;Fagundes et al, 2020) and biotic factors such as predators and parasitic or mutualistic microorganisms (Moles and Westoby, 2006;Farias et al, 2015;Fernandes et al, 2019).…”

“…(Fabaceae) is a tropical shrub that occurs in anthropized areas of the Brazilian Cerrado (Veloso et al, 2017). This plant species often invades cultivated agricultural areas and pastures, causing economic losses for rural producers (Fagundes et al, 2020). The aims of this study were (i) identify EFs associated with the leaves of C. oblongifolia and (ii) evaluate the effects of culture filtrates of these EFs on seed germination and seedling development of C. oblongifolia.…”