An increasing number of studies on tropic responses includes the genetic analysis of mutants defective in these morphogenetic processes. This review collates the information and discusses the implications of this approach to such studies. The review is organized on a systematic basis because most genetic analyses are insufficiently complete for general principles to have emerged. The most advanced analyses are those of lower eukaryotes because of their haploidy and the ease with which they can be manipulated in vitro. The extensive studies of phototropism, gravitropism and autochemotropism in the fungus Phycomyces blakesleeanus and of phototropism, polarotropism and gravitropism in the moss Physcomitrella patens are reviewed. In comparison with these studies, the genetic analysis of tropic responses in particular species of flowering plants is more limited. However, comparative physiological and ultra-structural studies of individual mutant and wild-type strains have been performed for a number of species. These results are discussed with particular regard to their support for established hypotheses.

中文翻译：

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热带反应的遗传分析

越来越多的热带反应研究包括对这些形态发生过程中存在缺陷的突变体进行遗传分析。本综述整理了信息并讨论了这种方法对此类研究的影响。该评价是在系统的基础上组织的，因为大多数遗传分析都不够完整，无法出现一般原则。最先进的分析是对低等真核生物的分析，因为它们是单倍体，并且可以在体外轻松操作。综述了真菌 Phycomyces blakesleeanus 的向光性、向地性和自趋化性以及苔藓 Physcomitrella patens 的向光性、极地性和向地性的广泛研究。与这些研究相比，对特定开花植物物种的热带反应的遗传分析更为有限。然而，已经对许多物种进行了个体突变株和野生型菌株的比较生理学和超微结构研究。讨论这些结果时特别考虑了它们对既定假设的支持。