Optimizing Leaf Hydration through Light Intensity and Color Ratios Potentially Improving Agricultural Practices

Researchers from Hebrew University have unveiled the intricate connection between light conditions, Blue-Light (BL) to Red-Light (RL) ratio, and leaf hydraulic conductance (Kleaf) in different canopy areas. The study shows that light not only directly impacts photosynthesis but also indirectly affects water demands and hydraulic conductance. These findings offer insights into plant adaptive strategies, potentially improving agricultural practices, especially in water management for better crop productivity.


[Hebrew University of Jerusalem, Israel] – The recent study led by Prof. Menachem Moshelion from The Robert H. Smith Faculty of Agriculture, Food and Environment at The Hebrew University along with Dr. Yael Grunwald and Dr. Adi Yaara from the same institute have unveiled the intricate relationship between light conditions, particularly the Blue-Light (BL) to Red-Light (RL) ratio, and leaf hydraulic conductance (Kleaf) across various canopy areas has been revealed. The plant canopy, essentially the upper layer of vegetation in a plant, plays a crucial role in light interception and photosynthesis, acting as the vital connection between plants and their surroundings, is heavily influenced by factors such as light intensity and quality, profoundly impacting photosynthesis—a fundamental process in plant growth. This investigation unveils how these light variations impact all aspects of plant hydraulic and gas conductance. This study focuses on how the balance of blue and red light in these bright areas helps control the water flow within plant leaves. It does this by affecting the water permeability of cells near the plant’s vascular tissue (the plant’s water transport system), which meets the high water demand. On the other hand, in shaded areas, where there’s less light, plants have lower water needs. These shaded leaves are more efficient in using water because they lose less water through transpiration, and they still support photosynthesis (a fundamental process) for plant growth due to the presence of red light​​.This research explores the intricate mechanisms through which plants adapt to diverse environments, offering crucial insights for optimizing agricultural approaches, especially in regions where water management is critical, and deepening our comprehension of plant physiology.


Conversely, shaded inner-canopy areas experience lower light intensity, reduced water demands, and diminished leaf water transport due to lower intensity and BL induction. Intriguingly, despite these differences, shaded leaves exhibit higher water-use efficiency compared to their counterparts in the upper canopy. This heightened efficiency is attributed to decreased transpiration and cooling requirements in the shaded areas, while the presence of RL supports photosynthesis.


The study sheds light on the dynamic interplay between light conditions, water demands, and hydraulic conductance within different canopy regions, offering valuable insights into the adaptive strategies plants employ to thrive in varying environments.


The findings of this research not only contribute to our understanding of plant physiology but also have potential applications in optimizing agricultural practices, especially in areas where water management is crucial for crop productivity.


The research paper titled “Illuminating plant water dynamics: the role of light in leaf hydraulic regulation” is now available in New Phytologist and can be accessed at https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.19497.




Yael Grunwald1,2, Adi Yaaran1, Menachem Moshelion1


* This pioneering work is rooted in the exceptional Ph.D. theses of two young female scientists, Dr. Yael Grunwald and Dr. Adi Yaaran. Their doctoral research laid the groundwork for the models discussed in the papers resulting from their Ph.D. studies, which were published in esteemed journals like Plant Cell, Plant Physiology, New Phytologist, and The Plant Journal. This publication record reflects the high regard their work commands within the scientific community. Their achievements are particularly noteworthy, considering the additional responsibilities they shouldered as young mothers during their research journey. Balancing family life with the demands of advanced scientific research is an impressive feat, underscoring their dedication and resilience in their respective fields.



1) The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem

2) current position at the Plant & Environmental Sciences Department, Weizmann Institute of Science



We would like to express our deep appreciation to Prof. Nava Moran, Dr Tanmayee Torne Shrivastava, and Dr Sanbon Chaka Gosa for their insightful contributions in shaping the BSC BLSTP theory. Their expertise and input have been invaluable in this endeavor. This research was supported by the Israel Science Foundation (ISF) grant no. 1043/20.


Disclaimer: In these challenging times of war and crisis, Hebrew University of Jerusalem is resolute in its dedication to advancing research and education. We stand in full support of the brave individuals on the frontlines, safeguarding our nation and the well-being of all Israelis, and extend our deepest gratitude and unwavering solidarity to our community and fellow citizens. Together, we shall prevail against the challenges that confront us, and our shared commitment to the well-being of all Israelis and the pursuit of knowledge remains resolute.

The Hebrew University of Jerusalem is Israel’s premier academic and research institution. With over 25,000 students from 90 countries, it is a hub for advancing scientific knowledge and holds a significant role in Israel’s civilian scientific research output, accounting for nearly 40% of it and has registered over 11,000 patents. The university’s faculty and alumni have earned eight Nobel Prizes and a Fields Medal, underscoring their contributions to ground-breaking discoveries. In the global arena, the Hebrew University ranks 86th according to the Shanghai Ranking. To learn more about the university’s academic programs, research initiatives, and achievements, visit the official website at http://new.huji.ac.il/en

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