A distributive '50% rule' determines floral initiation rates in the Brassicaceae

Male Germ Cell Specification in Plants

Germ cells (GCs) serve as indispensable carriers in both animals and plants, ensuring genetic continuity across generations. While it is generally acknowledged that the timing of germline segregation differs significantly between animals and plants, ongoing debates persist as new evidence continues to emerge. In this review, we delve into studies focusing on male germ cell specifications in plants, and we summarize the core gene regulatory circuits in germ cell specification, which show remarkable parallels to those governing meristem homeostasis. The similarity in germline establishment between animals and plants is also discussed.

Integrated dominance mechanisms regulate reproductive architecture in Arabidopsis thaliana and Brassica napus

The production of seed in flowering plants is complicated by the need to first invest in reproductive shoots, inflorescences, flowers, and fruit. Furthermore, in many species, it will be months between plants generating flowers and setting seed. How can plants therefore produce an optimal seed-set relative to environmental resources when the "reproductive architecture" that supports seed-set needs to be elaborated so far in advance? Here, we address this question by investigating the spatio-temporal control of reproductive architecture in Arabidopsis (Arabidopsis thaliana) and Brassica napus. We show that resource and resource-related signals such as substrate volume play a key role in determining the scale of reproductive effort, and that this is reflected in the earliest events in reproductive development, which broadly predict the subsequent reproductive effort. We show that a series of negative feedbacks both within and between developmental stages prevent plants from over-committing to early stages of development. These feedbacks create a highly plastic, homeostatic system in which additional organs can be produced in the case of reproductive failure elsewhere in the system. We propose that these feedbacks represent an "integrated dominance" mechanism that allows resource use to be correctly sequenced between developmental stages to optimize seed set.

Bloom and bust: understanding the nature and regulation of the end of flowering

The reproduction of flowering plants is an incredibly important process, both ecologically and economically. A huge body of work has examined the mechanisms by which flowering plants correctly time their entry into the reproductive phase (the 'floral transition'). However, the corresponding mechanisms by which plants exit the reproductive phase remain relatively neglected. In this review, we identify four developmental processes that contribute to the end-of-flowering; floral arrest, inflorescence meristem arrest, inflorescence activation and 'vegetative transition'. We highlight that, due to the highly divergent nature of reproductive systems among flowering plants, these processes are differently important for end-of-flowering in different species. For each of these processes, we examine recent advances in understanding the regulatory mechanisms that govern the process, and how these mechanisms determine the timing of end-of-flowering.