Crop Physiology Lesson: Plant Water Relations Water Potential and Transport
- PlantHouse Enterprise
- 2 days ago
- 2 min read
Original video: https://youtu.be/v-xTdfeac20
Lecture on: 3 November 2025
This lecture, part of the Crop Physiology (AGR3301) course, provides a deep dive into the properties of water, the movement of water within the plant (transport), and the fundamental concept of Water Potential.
Water Properties and Transport. We begin by reviewing the unique characteristics of water, focusing on its role in plant function:
1. Polarity and Bonding: Water's polarity leads to hydrogen bonding, driving cohesion (water sticking to water) and adhesion (water sticking to non-water molecules).
2. Thermal Properties: Water's high specific heat capacity allows it to absorb significant heat without large temperature changes, and its high heat of vaporization is critical for cooling leaves through transpiration.
3. Xylem Transport: We illustrate how cohesion and adhesion work together to draw water up the xylem vessels against gravity, creating the necessary water potential gradient from the soil to the atmosphere.
Environmental Influences (VPD) Finally, the lecture addresses how the atmospheric environment affects plant water status through Vapor Pressure Deficit (VPD):
1. VPD vs. Relative Humidity (RH): VPD is the difference between the saturated vapor pressure inside a healthy leaf (always 100% RH) and the actual vapor pressure of the surrounding air.
2. Impact on Plant Health: High VPD causes faster transpiration, which can lead to rapid nutrient uptake (risk of toxicity) and potential wilting. Low VPD slows transpiration, which can increase vulnerability to fungal diseases
Keywords: Water Potential, Water Relations, Plant Physiology, Transpiration, Cohesion-Tension Theory, Vapor Pressure Deficit, VPD, Solute Potential, Pressure Potential, Osmosis, Plant Transport, AGR3301.
Location:
Faculty of Agriculture, Universiti Putra Malaysia
Fakulti Pertanian, Universiti Putra Malaysia, 43000 Seri Kembangan, Selangor
2.983567621706455, 101.73466120334834
Attribution 4.0 International — CC BY 4.0 - Creative Commons
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