January 26, 2024 — A new study by the Hebrew University of Jerusalem details the impact of light on various plant processes across different areas of a plant leaf, offering valuable insights into the adaptive strategies in water management for better crop productivity.

The study, published in New Phytologist, measures the impact of light, which indirectly affects water demands and hydraulic conductance as well as photosynthesis. The plant canopy, essentially the upper layer of vegetation in a plant, plays a crucial role in light interception particularly the Blue-Light (BL) to Red-Light (RL) ratio, and leaf hydraulic conductance (Kleaf).

At the top of the canopy, the plant experiences significant water loss due to the high heat and humidity due to intense light conditions. This process creates a significant demand for water supply, which necessitates efficient hydraulic conductance throughout the plant.

In shaded inner canopy areas where less light penetrates, plants have lower water needs. These shaded leaves lose less water through transpiration yet support photosynthesis with available red light. Despite these differences, shaded leaves exhibit higher water-use efficiency compared with their upper canopy counterparts.

According to Prof. Menachem Moshelion of the Hebrew University Robert H. Smith Faculty of Agriculture, Food, and Environment, “These findings inform species selection for ecosystems, optimize lighting for indoor farming, and fine tunes water-management practices, especially in areas where water management is crucial for crop productivity.”

The research was based on the theses by two Hebrew University Ph.D. candidates, Dr. Yael Grunwald and Dr. Adi Yaara, and was supported by the Israel Science Foundation (ISF) grant no. 1043/20.

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

Yael Grunwald1,2, Adi Yaaran1, Menachem Moshelion1

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)  Plant & Environmental Sciences Department, Weizmann Institute of Science