Seed characterization of Allamanda puberula A. DC. and seedling production

Allamanda puberula is a native species of the Caatinga biome with ornamental and landscaping potential. However, its potential is little explored due to the lack of information about the biology of its seeds and propagation. In this context, a study was carried out in order to characterize the seeds and their potential to produce seedlings in different containers. The experiments were divided into two phases. The first consisted in the characterization of fruits and seeds by evaluating the number of seeds per fruit, their dimensions (length and width), the weight of a thousand seeds, the number of seeds kg-¹, the degree of moisture, germination and emergence. The second phase consisted in the production of seedlings in a nursery, evaluating the growth over the days after sowing (DAS) (15, 30, 45 and 60 DAS) and the effect of the type of container (trays and tubes) for the formation of the seedlings. The species A. puberula has small seeds and a significant number of seeds per fruit. Apparently, there is no physical impediment or type of dormancy that impairs the germination process of the seeds. Seedlings grown in tubes were better in terms of growth and allocation of biomass. However, the indication of the best cultivation container for A. puberula propagated via seeds will depend on the implantation project and the specific characteristics of the field. The characterization of A. puberula seeds showed satisfactory physiological potential for germination and complete seedling formation in the nursery, enabling success in obtaining seedlings through seminiferous propagation.

Growth and Allocation of Woody Biomass in Forest Trees Based on Environmental Conditions

Terrestrial ecosystems, and forests in particular, are important components of land processes because of their key role in reducing atmospheric greenhouse gas concentrations by storing a large amount of carbon in tree biomass and soils [...]

Influence of Endomycorrhizal Fungi on the Growth of Tropical Plant Species

In Southeast Mexico, deforestation in tropical forests is considered an environmental concern. Deforestation favours the growth of plants that compete with species of interest, which generally present slow growth. In order to promote greater growth in less time of the forest species used in reforestation and two crops of regional interest, the effect of including Rhizophagus intraradices in the seed or the root system of seedlings were investigated to evaluate its influence on growth and allocation of dry matter in the aerial and radical part, in addition to the concentration of N, P and Ca. Also, two additional collections with morphological characteristics of Glomus sps were included in T. donnell-smithii. The results indicate that biofertilisation with R. intraradices induces increased growth and is differential in stem and root dry matter allocation over time, in addition to increasing nutrient content in plant tissue.

Females and hermaphrodites of the gynodioecious Geranium maculatum respond similarly to soil nutrient availability

Sexual dimorphism in plant growth and/or reproductive responses to the surrounding environment has been documented in some plant species. In gynodioecious plants, it is especially important to understand whether females and hermaphrodites differ in their response to environmental stressors, as the fitness of females relative to hermaphrodites determines the extent to which these separate sexes are maintained in natural populations. Soil nutrient availability is of particular importance given the different nutrient requirements of male and female sexual functions in plants. Here, we evaluated and compared the growth of females and hermaphrodites of Geranium maculatum in response to varying levels of nutrients. Using a greenhouse experiment, we manipulated the overall nutrient, nitrogen, and phosphorus levels in the soil and measured growth, allocation, and leaf quality responses in both females and hermaphrodites. We found that sexes responded similarly in their growth and allocation responses to nutrient availability, albeit evidence that female leaf chlorophyll content may have increased more than that of hermaphrodites across soil nitrogen levels. Our findings demonstrate that hermaphrodites differ from females in terms of their physiological response to varying nutrient levels, however these physiological differences did not translate into meaningful growth or reproduction differences.

Enhanced shoot investment makes invasive plants exhibit growth advantages in high nitrogen conditions

Resource amendments commonly promote plant invasions, raising concerns over the potential consequences of nitrogen (N) deposition; however, it is unclear whether invaders will benefit from N deposition more than natives. Growth is among the most fundamental inherent traits of plants and thus good invaders may have superior growth advantages in response to resource amendments. We compared the growth and allocation between invasive and native plants in different N regimes including controls (ambient N concentrations). We found that invasive plants always grew much larger than native plants in varying N conditions, regardless of growth- or phylogeny-based analyses, and that the former allocated more biomass to shoots than the latter. Although N addition enhanced the growth of invasive plants, this enhancement did not increase with increasing N addition. Across invasive and native species, changes in shoot biomass allocation were positively correlated with changes in whole-plant biomass; and the slope of this relationship was greater in invasive plants than native plants. These findings suggest that enhanced shoot investment makes invasive plants retain a growth advantage in high N conditions relative to natives, and also highlight that future N deposition may increase the risks of plant invasions.