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Rafflesia is an endangered endophytic holoparasitic plant that lives the majority of its life inside the tissues of its sole plant host, Tetrastigma. Rafflesia floral buds emerge to produce the world's largest single flower. Like other plants, holoparasites harbor a diverse microbiome, the role(s) of which has remained largely unstudied. We characterized the bacterial microbiome of seeds of Rafflesia speciosa and cuttings of its host. We found evidence that R. speciosa seed has similar bacterial profiles to its infected host, which suggests that seeds sequester certain host bacteria, as well as acquire unique bacterial taxa from biotic associates of the fruit. We did not find evidence of mycorrhizal taxa in the microbiome. This is the first study of the microbial endophytes associated with any Rafflesia species and its host, a tripartite holobiont, and provides insights on its cryptic microbial partners. We discuss how this may aid horticultural propagation of Rafflesia. [ABSTRACT FROM AUTHOR]

Some students enter the world of mathematics with a disadvantage. The authors explored the causes for this from a language-processing perspective. They were particularly concerned with students with potential learning disabilities or specific language impairments. They also explored the role of language-mediated instruction in creating an accumulation of ambiguity in the instructional environment. They offer inferences on how this ambiguity may cause insecurities among young learners, and they suggest preemptive methodologies to better prepare young learners for formal mathematics education. (Contains 4 figures and 1 note.)

Determines the effect of raindrop impact and sheet erosion on infiltration rate and crust formation in soils. Rainfall simulation; Reduction in infiltration rate; Comparison of results on different soil types.

An infiltration equation was derived on the assumption that a drop upon impact with the soil compacts into final crust structure a small area. The size of this area is characteristic of the drop and the soil properties. Extensions of this model can treat spectrums of drops and variations of rainfall characteristics with time. The model applies to initially saturated homogeneous soil columns and leads to the conclusion that the reduction of infiltration capacity is not directly related to time but rather to the number of drops that hit the surface. The effect of the depth of the soil column on the final infiltration capacity is such that the deeper it is, the higher the final infiltration capacity, approaching a limit, which depends on the properties of the crust, not of the subsoil. It is suggested that comparisons between infiltration experiments in columns be made on the basis of the intrinsic value of the limiting infiltration capacity. [ABSTRACT FROM AUTHOR]

Societal Impact Statement Summary Rafflesia is a genus of parasitic plants with the largest flowers in the world, unique to the threatened forest habitats of tropical Asia. Here, we report on genes that are active (the transcriptome) in Rafflesia seeds as part of a larger effort to understand Rafflesia. Rafflesia has never been grown successfully outside of its native range. Consequently, seed banking is not yet possible, precluding a critical management strategy for conservation. The study of Rafflesia seed biology is a critical step to improve its cultivation, which will educate the public about unique species and the importance of conserving their habitats. Rafflesia is of great interest as one of the only two plants known to have completely lost its chloroplast genome. Rafflesia is a holoparasite and an endophyte that lives inside the tissues of its host, a tropical grape vine (Tetrastigma), emerging only to bloom—with the largest flower of any plant. Here, we report the first Rafflesia seed transcriptome and compare it with those of other plants to deepen our understanding of its extraordinary life history. We assembled a transcriptome from RNA extracted from seeds of the Philippine endemic Rafflesia speciosa and compared this with those of other plants, including Arabidopsis, parasitic plants Striga and Cuscuta, and the mycoheterotrophic orchid Anoectochilus. Genetic and metabolic seed pathways in Rafflesia were generally similar to the other plant species. However, there were some notable exceptions. We found evidence of horizontal transfer of a gene potentially involved in circumventing host defenses. Moreover, we identified a possible convergence among parasitic plants because Rafflesia, Striga, and Cuscuta shared important similarities. We were unable to find evidence of genes involved in mycorrhizal symbiosis, suggesting that mycoheterotrophy is unlikely to play a role in Rafflesia parasitism. To date, ex situ propagation of Rafflesia by seed has been mostly unsuccessful. Our research is a bold step forward in understanding the fundamentals of Rafflesia seed biology that will inform the continued propagation and seed‐banking efforts concerning this recalcitrant plant. We discuss our findings in the broader context of the conservation of a genus in peril. [ABSTRACT FROM AUTHOR]