Water stress in plants is one of the greatest challenges in modern agriculture, especially in light of global climate change. Water stress in plants is not a uniform condition, and understanding the differences between acute and chronic water stress is crucial for developing effective management strategies and ensuring future food security.

What is Acute Water Stress and When Does it Occur?

Acute water stress refers to a sudden and severe water shortage condition, lasting a relatively short period – from a few days to several weeks. This condition typically occurs as a result of extreme weather events such as sudden heat waves, strong dry winds, or sudden cessation of irrigation.

The plant responds to acute stress immediately and dramatically. The first response is rapid closure of stomata (breathing pores) to reduce water loss. This mechanism, despite its effectiveness in conserving water, causes a significant reduction in carbon dioxide absorption and thus a sharp decline in photosynthesis rate.

In extreme cases of acute stress, rapid wilting of leaves and stems can be observed as a result of turgor pressure loss in plant cells. This is a protective response that allows the plant to reduce the surface area exposed to evaporation.

How Does Chronic Water Stress Affect Plants in the Long Term?

Chronic water stress is characterized by prolonged and persistent water shortage, lasting months or even entire seasons. This type of stress occurs in arid and semi-arid regions, or during extended drought periods. Unlike acute stress, the plant must develop long-term survival strategies.

Under chronic stress, the plant undergoes profound structural and physiological changes. The root system expands and deepens to search for additional water sources in deeper soil layers. Comprehensive studies show that plants under chronic stress can develop root systems three times deeper than normal.

Plant-Ditech, founded on technology developed by Professors Menachem Moshelion and Rony Wallach from the Hebrew University of Jerusalem – world-renowned experts in plant stress physiology and soil and water sciences, has developed advanced technologies for monitoring and managing this chronic water stress.

What Happens at the Biochemical Level in Both Types of Stress?

At the biochemical level, the differences between acute and chronic stress are fundamental. In acute stress, the plant primarily activates immediate defense mechanisms such as ion flow changes in cell membranes and rapid signaling molecule creation.

In contrast, under chronic stress, the plant produces large quantities of osmolytes such as proline, sugars, and polyols. These substances help maintain cellular turgor pressure and protect cell proteins from salt and dehydration damage.

Additionally, under chronic stress, significant changes occur in gene expression. Many genes related to defense protein synthesis, antioxidant enzymes, and other protective molecules are expressed at significantly higher levels.

How Can Early Detection Change Outcomes?

Early detection of water stress, whether acute or chronic, is critical for effective crop management. In acute stress, rapid response can save the crop, while in chronic stress, long-term planning can significantly reduce damage.

New technologies such as optical and thermal sensors enable continuous monitoring of plant status. Advanced systems can detect changes in leaf temperature, chlorophyll levels, and light reflection even before visible signs of water stress appear.

The goal of Plant-Ditech researchers was to combine their complementary expertise to significantly impact ensuring future food production in the face of global climate change, by developing optimal processes and technologies for improving crop yields, especially under stress conditions.

Which Management Strategies Suit Each Type of Stress?

Acute stress management focuses on rapid and efficient response. Immediate irrigation and temporary shading can save the crop. In extreme cases, foliar spraying with water can provide immediate relief by reducing leaf temperature.

In contrast, chronic stress management requires a strategic and long-term approach. This includes selecting drought-resistant varieties, improving soil water retention capacity by adding organic matter, and developing efficient irrigation systems such as drip irrigation.

Adapting cultivation patterns to local conditions becomes critical. This includes changing planting dates, adjusting planting densities, and implementing conservation agriculture techniques such as ground cover and reduced tillage.

What Does the Future Hold in Water Stress Research?

Future research in plant water stress focuses on several fascinating directions. Development of genetically engineered varieties with improved drought resistance is one of the prominent directions. Technologies like CRISPR enable precise editing of genes related to water stress resistance.

In the technology field, development of smart sensors and artificial intelligence systems enables accurate prediction of water stress even before it occurs. Advanced algorithms can analyze weather data, soil moisture, and plant status to predict when and where water stress might occur.

Nanotechnologies are also developing rapidly, with the development of nanoparticles that can improve soil water retention capacity or provide controlled-release nutrients under stress conditions.

Is There One Solution Suitable for All Types of Water Stress?

Despite impressive technological developments, it's important to understand that there is no single solution suitable for all types of water stress. The most effective approach is a combination of multiple strategies adapted to the specific conditions of each region and crop.

In environments with frequent acute stress, investment in rapid irrigation systems and early warning systems is critical. In areas with chronic stress, the focus should be on selecting appropriate crops, improving soil structure, and developing efficient long-term irrigation systems.

The integrated approach should also include landscape management aspects, biodiversity conservation, and strengthening the resilience of entire agricultural ecosystems against climate change challenges.