A review, published in Plant Physiology by Ran et al. (2023), investigates how cytokinins, particularly zeatin, regulate rhizome growth and development in Kentucky bluegrass.
If you're a turf manager or enthusiast, you know that healthy rhizome growth is essential for a lush, resilient Kentucky bluegrass. But did you know that behind the scenes, tiny molecules called phytohormones, specifically cytokinins, play a vital role in how well your turfgrass thrives? The review sheds light on how cytokinins, particularly zeatin, impact the development of rhizomes in Kentucky bluegrass, offering new insights into optimizing turf management strategies.
Why Rhizome Growth Matters for Kentucky Bluegrass
Kentucky bluegrass (Poa pratensis) is a cool-season turfgrass known for its ability to spread through rhizomes—underground stems that give rise to new shoots. Rhizomes are key for turfgrass recovery, density, and overall health, especially after wear and tear from foot traffic or environmental stress. It is also important for storing nutrients during colder months. The more vigorous the rhizome growth, the better the turfgrass can maintain its lush, uniform appearance.
However, not all Kentucky bluegrass varieties are equal in terms of rhizome growth. Some types, like the multi-rhizome variety 'Yuzhong,' produce abundant rhizomes, while others, like the few-rhizome variety 'Anding,' produces less. So, what’s the difference? According to Ran et al. (2023), the answer lies in the phytohormone balance—specifically, cytokinins.
Start applying microbials today with our Fall Program. Designed for those who want to get started in microbial inoculants right away.
The Role of Cytokinin in Kentucky Bluegrass and Rhizome
Cytokinins are a class of phytohormones that regulate various aspects of plant growth, from cell division to shoot and root development. In Kentucky bluegrass, zeatin (ZT), a type of cytokinin, has been identified as a key player in promoting rhizome growth. The study provided strong evidence that cytokinins (zeatin) play a crucial role in promoting rhizome growth and development in Kentucky bluegrass. Higher levels of zeatin are associated with increased rhizome number, diameter, and internode length. Conversely, higher levels of indole-3-acetic acid (IAA, a type of auxin), abscisic acid (ABA), and gibberellic acid (GA₃) are associated with reduced rhizome development, suggesting an inhibitory effect.
The significant enrichment of metabolites in the histidine metabolism and ABC transporter pathways, both related to cytokinin synthesis and transport, further supports the pivotal role of cytokinin in rhizome growth. The robust statistical analyses, significant correlations, and consistency with previous research underscore the reliability of the findings.
One of the most fascinating findings of the study was the importance of the ZT/ABA ratio. A higher ratio of zeatin to abscisic acid (ABA) was directly correlated with stronger rhizome development. In simple terms, the more zeatin in relation to ABA, the more likely the turf will produce rhizomes.
What This Means for Kentucky Bluegrass Management
Understanding how cytokinins like zeatin influence rhizome growth opens up new possibilities for turfgrass management.
Here are a few practical takeaways for turf managers based on Ran et al. (2023):
Enhance Rhizome Growth for Resilience: Turf with more rhizomes is better equipped for winter and to recover from damage/stress. Having a thoughtful and balanced fertilization regime in the fall will help the turf focus more on growing instead of stress.
Aeration and Soil Management: Ensuring the soil is well-aerated and not compacted enhances water penetration and root growth. Well-developed root systems help turfgrass access deeper soil moisture during drought, reducing the stress that triggers excessive ABA signaling.
The Science of Turfgrass and Rhizome is Evolving
The research by Ran et al. (2023) provides a deeper understanding of the hormonal controls behind rhizome development in Kentucky bluegrass. By focusing on cytokinins, particularly zeatin, turf managers can unlock new strategies to improve turf density, resilience, and overall health.
With ongoing advancements in turfgrass research, the future of turf management will likely involve a more nuanced understanding of how to manipulate plant hormones and metabolites to achieve optimal growth. For now, promoting healthy rhizome development through hormonal balance could be the key to maintaining the beautiful, green turfgrass you strive for.
You can read more about the paper here:
Ran F, Bai X, Li J, Yuan Y, Li C, Li P, Chen H. Cytokinin and Metabolites Affect Rhizome Growth and Development in Kentucky Bluegrass (Poa pratensis). Biology (Basel). 2023 Aug 11;12(8):1120. doi: 10.3390/biology12081120. PMID: 37627004; PMCID: PMC10452147.
To learn more about the En-Turf Starter Program and begin your journey towards more resilient turf.