The durian (genus Durio) has aroused curiosity among botanists for centuries, and influenced local culture across Southeast Asia for millennia. Of the 30 described species of Durio, about a third produce edible fruits, yet just one (Durio zibethinus) is grown on a commercial scale. Several new species have been described recently, which may be a reservoir of important genetic resources. Meanwhile, unregulated durian cultivation triggered by rapidly growing demand and a high return on investment may pose a threat to natural forests. Here we review recent findings in the genus with a focus on Malaysia and Indonesia. We suggest that further research into obscure wild relatives and local cultivars, will be important in the context of growing international demand for durian, coupled with an increasing reliance on commercial cultivars of this economically and culturally important fruit. Finally we suggest greater attention should be given to the potential threat to biodiversity posed by illegal durian plantations in one of the most biodiverse regions of the planet.
4 September 2019 in Journal of The Royal Society Interface
We show how anisotropic, grooved features facilitate the trapping and directed transport of droplets on lubricated, liquid-shedding surfaces. Capillary action pins droplets to topographic surface features, enabling transport along the feature while inhibiting motion across (or detachment from) the feature. We demonstrate the robustness of this capillary-based mechanism for directed droplet transport on slippery surfaces by combining experiments on synthetic, lubricant-infused surfaces with observations on the natural trapping surface of a carnivorous pitcher plant. Controlling liquid navigation on synthetic surfaces promises to unlock significant potential in droplet-based technologies. Our observations also offer novel insight into the evolution of the Nepenthes pitcher plant, indicating that the ‘pitfall’ trapping mechanism is enhanced by the lubricant-infused, macroscopic grooves on the slippery peristome surface, which guide prey into the trap in a way that is more tightly controlled than previously considered.
Summary: Endoparasitic plants are the most reduced flowering plants, spending most of their lives as a network of filaments within the tissues of their hosts. Despite their extraordinary life form, we know little about their biology. Research into a few species has revealed unexpected insights, such as the total loss of plastome, the reduction of the vegetative phase to a proembryonic stage, and elevated information exchange between host and parasite. To consolidate our understanding, we review life history, anatomy, and molecular genetics across the four independent lineages of endoparasitic plants. We highlight convergence across these clades and a striking trans‐kingdom convergence in life history among endoparasitic plants and disparate lineages of fungi at the molecular and physiological levels. We hypothesize that parasitism of woody plants preselected for the endoparasitic life history, providing parasites a stable host environment and the necessary hydraulics to enable floral gigantism and/or high reproductive output. Finally, we propose a broader view of endoparasitic plants that connects research across disciplines, for example, pollen–pistil and graft incompatibility interactions and plant associations with various fungi. We shine a light on endoparasitic plants and their hosts as under‐explored ecological microcosms ripe for identifying unexpected biological processes, interactions and evolutionary convergence.
The giant Amazonian waterlily (genus Victoria ) produces the largest floating leaves in the plant kingdom. The leaves’ notable vasculature has inspired artists, engineers, and architects for centuries. Despite the aesthetic appeal and scale of this botanical enigma, little is known about the mechanics of these extraordinary leaves. For example, how do these leaves achieve gigantic proportions? We show that the geometric form of the leaf is structurally more efficient than those of other smaller species of waterlily. In particular, the spatially varying thickness and regular branching of the primary veins ensures the structural integrity necessary for extensive coverage of the water surface, enabling optimal light capture despite a relatively low leaf biomass. Leaf gigantism in waterlilies may have been driven by selection pressures favoring a large surface area at an economical material cost, for outcompeting other plants in fast-drying ephemeral pools.
Societal Impact Statement: Rafflesia is the genus that contains the world's largest flowers. Despite their global appeal, most of the 42 known species are now at risk of extinction. Urgent action is needed to protect these remarkable flowers. A combined approach to conservation is recommended, including a greater level of habitat protection and support for local community action groups. Rafflesia is a suitable new icon for conservation in the Asian tropics.Summary: The genus Rafflesia, which includes the world's largest flowers, has aroused curiosity among scientists for centuries and features prominently in local culture across Southeast Asia. The plant has long been used in ethnobotanical medicine and, more recently, as a source of revenue from ecotourism. But despite its acclaim, Rafflesia remains poorly understood in many respects. Taxonomy is disputed, new species are described each year, and the plant has proven recalcitrant to cultivation. This has hindered conservation, and most of the 42 known species are now severely threatened, yet only one is listed by the International Union for Conservation of Nature (IUCN). We estimate that 60% of Rafflesia species face a severe risk of extinction (equivalent to Critically Endangered [CR]). Moreover, we predict that at least 67% of known habitats fall outside protected areas, exacerbating their vulnerability. Alarmingly, recent observations suggest taxa are still being eradicated before they are even known to science. We present recent scientific discoveries and probable extinctions and highlight case studies of conservation success, with a focus on the role of local people. We propose a multi‐pronged conservation approach combining strengthened taxonomy, ex situ propagation, ecotourism, and an extension of protected areas. We suggest action devolved to local communities and awareness campaigns linked to social media networks will be crucial outside of protected jurisdictions. Finally, we propose to establish Rafflesia as a new icon for plant conservation in the Asian tropics. A combined approach might just save some of the world's most remarkable flowers, most of which are now on the brink of being lost.