Some plants stop growing and die after producing fruits, here’s why
- Monocarpic plants are plants that die after producing fruits.
- When these plants reach certain number of fruits, flower production stops and cells responsible for growth cease dividing.
- This process of cessation is called proliferative arrest which ensures that nutrient is available for the formation of seeds.
- Proliferative arrest is an agricultural interest because it influences the flowering time scale and fruit production.
- The mechanism behind the initiation of the flowering period is well studied.
- However, the regulatory pathways and cellular processes that take part in the flowering cessation and triggering proliferative arrest is not well understood.
- Researchers identified the molecular and cellular changes associated with cell division and tissue growth in the shoot apical meristem throughout the flowering time period and proliferative arrest.
- Shoot apical meristem is the region of a plant that contains multipotent stem cells responsible for the development of plant organs above the ground.[1]
- Researchers discovered that before proliferative arrest occurs, cytokinin signaling was suppressed.
- Cytokinin is a plant hormone that induces cytokinesis or plant growth.[2]
- Additionally, researchers observed that repression of type B cyclins and WUSCHEL is correlated with proliferative arrest.
- B cyclins are proteins involved in the process of cell cycle.[3]
- WUSCHEL is a master regulator involved in plant growth signaling.[4]
- These molecular changes were observed to go along with changes in cell number and size.
- A separate analysis revealed that a mutation in FUL does not trigger proliferative arrest.
- FUL is the gene associated with controlling flowering time, meristem identity and leaf formation.[5]
- The study determined two phases that lead to proliferative arrest: early reduction and late blocking of cytokinin-related events.
Sources:
Paz Merelo et al. (2021). A cellular analysis of meristem activity at the end of flowering points to cytokinin as a major regulator of proliferative arrest in Arabidopsis, Current Biology. DOI: 10.1016/j.cub.2021.11.069
[1] https://www.nature.com/subjects/shoot-apical-meristem
[2] https://en.wikipedia.org/wiki/Cytokinin
[3] https://en.wikipedia.org/wiki/Cyclin_B
[4] https://link.springer.com/article/10.1007/s00299-020-02511-5
