Browsing by Author "de Boer, Hugo"

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    EthnobotanicalknowledgeandthreatfactorsforAloespeciesinTanzania
    (Ethnobotany Research & Applications, 2019-12) Abihudi, Siri; de Boer, Hugo; Mahunnah, Rogasian; Treydte, Anna
    Background: The genus Aloe has long been known for its use in healthcare and cosmetics. In Tanzania, overexploitation is threatening some Aloe species with extinction and yet, little has been documented on the abundance and biocultural uses. Material and Methods: Semi-structured questionnaires were used to obtain ethnobotanical information from 236 respondents across 22 villages in four regions of Tanzania (Kilimanjaro, Tanga, Mara, Katavi-Rukwa). Results: A total of 23 Aloe species were identified, 20 of which were being used locally and were mostly being collected from the wild. We report the uses of A. mzimbana, A. volkensii subsp. volkensii, A. leptosiphon, A. parvidens and A. bicomitum for the first time in East Africa. The most preferred species were A. lateritia, A. duckeri and A. secundiflora which are three common, widely distributed species. Diseases frequently treated with Aloe species include malaria and general stomachache in humans, and Newcastle disease in chickens. Some Aloe species were found to have gone extinct locally due to over-harvesting. Rare Aloe species were perceived to be less preferred as they mostly occurred far away from settlements. Conclusions: We conclude that the genus Aloe is widely used across Tanzania and needs strong conservation measures to prevent individual species from becoming extinct in the wild.
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    Species-specific responses of “Critically Endangered” and “Least Concern” Aloe seed germination to environmental conditions in Tanzania
    (Elsevier B.V., 2020-12) Abihudi, Siri; Venkataramana, Pavithravani; de Boer, Hugo; Treydte, Anna
    The majority of Aloe species are threatened by anthropogenic activities, trade, and the effects of climate change, but little is known on seed biology and appropriate conservation measures. Hence, understanding the germination behaviour of Aloe species will help in mitigating the negative effect of changing environmental conditions. “Critically Endangered” (A. boscawenii and A. pembana) and “Least Concern” (A. lateritia, A. volkensii and A. secundiflora) Aloe species’ seed germination was tested under various environmental parameters which are said to be crucial for Aloe species seed germination and included treatments of possible climate change scenarios. We varied temperature, light, scarification, KNO3 addition and salinity and compared the response of the “Critically Endangered” versus the “Least Concern” Aloe species. “Least Concern” Aloe species were used as a control because they have adapted to a wide range of environmental conditions in contrast to “Critically Endangered” Aloe species, which often have a restricted range and specific environmental needs. All Aloe species germinated best at moderate temperatures (25 Ce30 C) and low KNO3 levels (0.01 mg/l). Dark conditions triggered higher germination percentages for all Aloe species except for A. boscawenii. Saline water suppressed the germination of all Aloe species compared to Aloe species grown in distilled water medium only. Aloe seeds grown in filter paper distilled water medium germinated better than Aloe seeds grown on a soil medium. The “Least concern” (IUCN Red List) A. lateritia germinated better than other species, followed by “Critically endangered” A. pembana and A. secundiflora. Generally, Aloe seed germination is nurtured by moderate temperatures and low concentrations of KNO3. Hence, the effect of global warming will affect the survival of mostAloe species. The better germinationperformance under shade highlights the importance of parent plants, or at least a healthy canopy cover, in the Aloe species habitat. Aloe seeds showed species-specific responses to various environmental conditions (except for A. pembana), which reflects their Red List status