Stewart J Ryan
Department of Plant and Wildlife Sciences, Brigham Young University Provo, UT, USA.
Front Plant Sci. 2015 Sep 24;6:684. doi: 10.3389/fpls.2015.00684. eCollection 2015.
As climate change leads to drier and warmer conditions in semi-arid regions, growing resource-intensive C3 and C4 crops will become more challenging. Such crops will be subjected to increased frequency and intensity of drought and heat stress. However, agaves, even more than pineapple (Ananas comosus) and prickly pear (Opuntia ficus-indica and related species), typify highly productive plants that will respond favorably to global warming, both in natural and cultivated settings. With nearly 200 species spread throughout the U.S., Mexico, and Central America, agaves have evolved traits, including crassulacean acid metabolism (CAM), that allow them to survive extreme heat and drought. Agaves have been used as sources of food, beverage, and fiber by societies for hundreds of years. The varied uses of Agave, combined with its unique adaptations to environmental stress, warrant its consideration as a model CAM crop. Besides the damaging cycles of surplus and shortage that have long beset the tequila industry, the relatively long maturation cycle of Agave, its monocarpic flowering habit, and unique morphology comprise the biggest barriers to its widespread use as a crop suitable for mechanized production. Despite these challenges, agaves exhibit potential as crops since they can be grown on marginal lands, but with more resource input than is widely assumed. If these constraints can be reconciled, Agave shows considerable promise as an alternative source for food, alternative sweeteners, and even bioenergy. And despite the many unknowns regarding agaves, they provide a means to resolve disparities in resource availability and needs between natural and human systems in semi-arid regions.
随着气候变化导致半干旱地区气候愈发干燥和炎热，种植资源密集型的C3和C4作物将变得更具挑战性。这类作物将面临干旱和热应激发生频率增加、强度加大的情况。然而，龙舌兰比菠萝（凤梨）和仙人掌（仙人掌属及相关物种）更能代表高产植物，无论是在自然环境还是栽培环境中，它们都能很好地应对全球变暖。龙舌兰分布于美国、墨西哥和中美洲，有近200个品种，进化出了包括景天酸代谢（CAM）在内的多种特性，使其能够在酷热和干旱环境中生存。数百年来，龙舌兰一直被社会用作食物、饮料和纤维的来源。龙舌兰的多种用途，加上其对环境压力的独特适应性，使其有理由被视为一种典型的景天酸代谢作物。除了长期困扰龙舌兰酒行业的过剩和短缺的破坏性循环外，龙舌兰相对较长的成熟周期、单次结果的开花习性以及独特的形态，是其作为适合机械化生产的作物广泛种植的最大障碍。尽管存在这些挑战，但龙舌兰作为作物仍具有潜力，因为它们可以在边际土地上种植，但所需的资源投入比普遍认为的要多。如果这些限制能够得到解决，龙舌兰作为食物、替代甜味剂甚至生物能源的替代来源显示出相当大的前景。尽管关于龙舌兰还有许多未知之处，但它们提供了一种解决半干旱地区自然系统和人类系统之间资源可用性和需求差异的方法。
