Dissertation Research: Evolution of Growth Form and Phytochemical Consequences in Adenia (Passifloraceae)

植物的生长形态有可能预测植物的化学成分吗？我们用这项研究调查了生长形式的进化变化和植物化学变化之间的联系。西番莲属(Passifloraceae)为研究这一问题提供了理想的类群。大约有90种，在这个组中的物种已经多样化到乔木，多汁灌木，块茎草本，块茎藤本，尾状，须根藤本和藤本植物，以及在这些基本形式上的变种。除了这种显著的辐射生长方式外，这种化学成分也是多种多样的，似乎在植物与以腺毛虫为宿主的Acraea毛虫和各种食蟹科的相互作用中发挥了重要作用。通过构建西番莲属种间亲缘关系的分子系统学假说，我们希望检验该类群的单系性，并确定西番莲在西番莲科内的位置。在第二阶段的研究中，我们调查了茎解剖学的发展和进化，因为它与生长形式有关。我们测试了这样的假设，即祖先的生长形式是藤本植物(意味着乔木、灌木和草本植物是从藤本植物中衍生出来的)，以及在乔木和灌木中观察到的肉质是足形过程的结果。最后，我们将叶片氰化物发生和叶片单宁含量绘制在系统发育图上，以检验从分配理论和表观理论发展起来的假说。我们相信，氰化物的生成将在葡萄藤中最高，而单宁将最集中在其他更明显的生长形式中。此外，我们预测茎解剖的变化将与化学变化相关。Adenia的种类分布在东半球的热带地区。赫恩曾前往南非和东非，对那里的阿德尼亚山脉进行实地收集和观察。2001年秋冬两季，他将前往马达加斯加，研究在那里发现的20种阿德尼亚地方病。这一支持为开展马达加斯加研究、解剖研究以及部分分子和化学研究提供了资金。

Is it possible that a plant's growth form predicts plant chemistry? We investigate the association between evolutionary changes in growth form and shifts in plant chemistry with this research. The genus Adenia (Passifloraceae) provides an ideal group to research this and related questions. With ca. 90 species, species in this group have diversified into trees, succulent shrubs, tuberous herbs, tuberous vines, caudiciforms, fibrous rooted vines, and lianas, as well as variants on these basic forms. In addition to this remarkable growth form radiation, the chemistry is varied and appears to play an important role in the plants' interactions with Acraea caterpillars and various Chyrsomelidae which use Adenia as a host. By constructing a molecular phylogenetic hypothesis of the relationships of species in Adenia, we hope to test the monophyly of the group and determine where Adenia fits within the Passifloraceae family. During the second phase of the research, we investigate the development and evolution of stem anatomy as it relates to growth form. We test the hypotheses that the ancestral growth form is a vine (implying that the trees, shrubs, and herbs are derived from vines) and that the succulence observed in the trees and shrubs is a result of paedomorphic processes. Ultimately, we map leaf cyanogenesis and leaf tannin content on the phylogeny to test hypotheses developed from allocation theory and apparency theory. We believe that cyanogenesis will be highest in vines whereas tannins will be most concentrated in other more "apparent" growth forms. Furthermore, we predict that changes in stem anatomy will correlate with changes in chemistry. Species of Adenia are distributed throughout the Old-World tropics. Hearn has traveled to South and Eastern Africa to make field collections and observations of the Adenia there. This fall and winter, 2001, he will travel to Madagascar to research the 20 Adenia endemics found there. This DDIG support provides the funding to carry out both the Malagasy research, the anatomy research, and parts of the molecular and chemistry research.