Comparative study of steroidal sapogenins content in leaves of five Agave species

Lessons from the history of Agave: ecological and cultural context for valuation of CAM

BACKGROUND AND SCOPE

Crassulacean acid metabolism (CAM) is an intriguing physiological adaptation in plants that are widespread throughout many ecosystems. Despite the relatively recent mechanistic understanding of CAM in plant physiology, evidence from historical records suggests that ancient cultures in the Americas also recognized the value of CAM plants. Agave species, in particular, have a rich cultural legacy that provides a foundation for commercially valued products. Here, we review that legacy and potential relationships between ancient values and the needs of modern-day climate adaptation strategies.

CONCLUSIONS

There are many products that can be produced from Agave species, including food, sugar, fibre and medicines. Traditional knowledge about agricultural management and preparation of plant products can be combined with new ecophysiological knowledge and agronomic techniques to develop these resources in the borderland region of the southwestern USA and Mexico. Historical records of pre-Columbian practices in the Sonoran desert and remnants of centuries-old agriculture in Baja California and Sonora demonstrate the climate resilience of Agave agriculture. Commercial growth of both tequila and bacanora indicates the potential for large-scale production today, but also underscores the importance of adopting regenerative agricultural practices to accomplish environmentally sustainable production. Recent international recognition of the Appellation of Origin for several Agave species produced for spirits in Mexico might provide opportunities for agricultural diversification. In contrast, fibre is currently produced from several Agave species on many continents. Projections of growth with future climate change suggest that Agave spp. will be viable alternatives for commodity crops that suffer declines during drought and increased temperatures. Historical cultivation of Agave affirms that these CAM plants can supply sugar, soft and hard fibres, medicines and food supplements.

Research progress of diosgenin extraction from Dioscorea zingiberensis C. H. Wright: Inspiration of novel method with environmental protection and efficient characteristics

Diosgenin was the starting materials to synthesize various hormone drugs and mainly generated from Dioscorea zingiberensis C. H. Wright by acidolysis, enzymolysis, microbiological fermentation, and integrated manner. Only acidic hydrolysis with strong acid such as hydrochloric acid or sulfuric acid was used in practice in diosgenin enterprises due to their feasibility and simplicity, nevertheless finally resulting in a great deal of unmanageable wastewater and severely polluted the surrounding environment. Aiming to provide a comprehensive and up-to date information of researches on diosgenin production from this plant, 151 cases were collected from scientific databases including Web of Science, Pubmed, Science Direct, Wiley, Springer, and China Knowledge Resource Integrated (CNKI). Their advantages and disadvantages with different production methods were analyzed based on these available data in this review paper. Considering the fact that nearly all of diosgenin enterprises were closed for the environmental protection and the life health of the people, this review paper was beneficial for providing useful guidelines to develop novel technologies with environmentally-friendly and cleaner features for diosgenin production or facilitate the transformation of other methods like enzymolysis, microbiological fermentation, or integrated methods from laboratory scale to industry scale.

Agave americana: Characteristics and Potential Breeding Priorities

Agave americana L. is one of many Agave species that could be developed for the production of valuable agricultural products. Although all species in this genus use Crassulacean Acid Metabolism (CAM) and most have drought and heat tolerance, Agave americana also has the combined traits of high yield and cold tolerance. This review highlights key characteristics of Agave americana that make it an exceptional novel crop for fiber, sweeteners, bioproducts, and bioethanol with resilient traits for changing climate conditions. Then, it proposes potential directions for breeding that will support production in semi-arid climates. With selection and breeding, yields of 16 Mg ha⁻¹ y⁻¹ may be achieved. Current field observations, with no crop improvement, indicate ~9 Mg ha⁻¹ is the maximum yield, and in arid regions, a yield of ~3 Mg ha⁻¹ y⁻¹ is observed. It may be beneficial to breed for a shorter time to flowering, as has been successful for Agave tequilana Weber var. azul, so that further breeding goals are achievable in a decadal timespan. Specific trait selection during breeding will depend on whether fiber or sugar yields are the desired products at a given location. Even without breeding, varieties of Agave americana are climate resilient alternatives for some current commodity crops.