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

植物的生长形态是否可能预测植物的化学性质？本研究旨在探讨植物生长形态的进化变化与植物化学变化之间的关系。番槐属（Passifloraceae）为研究这一问题和相关问题提供了理想的类群。大约有90种，这个组的种已经分化成乔木、多肉灌木、块茎草本、块茎藤本植物、尾状植物、纤维根藤本植物和藤本植物，以及这些基本形式的变种。除了这种显著的生长形式，化学成分是多种多样的，似乎在植物与以腺虫为寄主的Acraea毛虫和各种Chyrsomelidae的相互作用中起重要作用。通过构建腺属植物种间亲缘关系的分子系统发育假说，我们希望检验该类群的单系性，并确定腺属植物在西番莲科中的位置。在研究的第二阶段，我们研究了茎解剖的发展和进化，因为它与生长形式有关。我们测试了祖先的生长形式是藤蔓的假设（这意味着树木、灌木和草本植物都是从藤蔓中衍生出来的），以及在树木和灌木中观察到的多肉质是幼胚过程的结果。最后，我们在系统发育上绘制了叶片的发绀和单宁含量图，以检验分配理论和显性理论提出的假设。我们认为，葡萄树的氰酸生成将是最高的，而单宁将在其他更“明显”的生长形式中最集中。此外，我们预测茎解剖结构的变化将与化学变化相关。腺虫的种类分布在整个旧大陆热带地区。赫恩曾前往非洲南部和东部实地收集和观察阿德尼亚。2001年秋冬，他将前往马达加斯加研究在那里发现的20种腺虫。DDIG的这项支持为马达加斯加研究、解剖学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.