The stomata of the olive tree - Factors that influence its closure-Water stress-

Plantae investigates the growth process of plants in our quest to improve the quality and production of the crops with controlled irrigation with our humidity and temperature sensors. Given the importance of watering well, we are going to assess how water stress affects the stomata of olive leaves .

Water stress is a consequence of the water deficit in the soil, therefore we try to deduce how the deficit affects the stomata, and that causes hydric stress to the olive tree.

What are olive stomata?

Stomata are pores that the plant has in the epidermal or protective tissue , which covers it except in the roots and the apical buds or flower buds. Its function is gas exchange and evaporation.

The olive leaf is:

  • Elongated and perennial, they persist on the tree for about three years.
  • With a very marked central rib and very small secondary ones.
  • The stomata of the olive leaf are on the underside and protected by fine threads that give it a silver tone.
Rama de olivo
Leaf parts

Role of the stomata of the olive tree in its development

The stomata of the olive tree have two functions:

  • Allow gas exchange , they absorb Carbonic Anhydride (CO2), carry out photosynthesis and release Oxygen (O2). It is as if the plant breathes through the stomata.
  • Maintain the water level of the plant . Water is the main component of the plant and carries the nutrients it needs from the roots. Through the stomata or pores, water is eliminated in the form of perspiration.

The plant opens or closes the stomata as it wants to retain water or not. It is normal that they do not have the same opening throughout the day, in the morning they are more open. In the afternoon they are partially closed to protect the plant because there is less humidity.

It is very important that they do not close completely because photosynthesis and perspiration are stopped.

Factors that influence the stomata of olive trees to close

The main factor that influences the closure of stomata is water stress , that is, when the water absorbed by the plant is less than it needs.

As the plant suffers drought or salinity, it closes its pores more, as if to protect the plant and make it conserve water, avoiding perspiration. The plant generates an acid called abscisic that causes the pores to close.

When you have water again, the stomata reopen. If the closure is total, even temporary, it alters the photosynthesis of the plant and induces a hormonal imbalance that stops its growth.

Estoma abierto
Open stomata. 1-Epidermis. 2-Occlusive cell. 3-Water. 4-Core. 5-Chloroplasts. 6-Occlusive or guard cell. 7-Water. 8-Core. 9-Potassium.

The use of soil moisture, temperature and electrical conductivity sensors help to control the irrigation policy, to optimize the balanced development of the plantation.

Effect of high temperatures on olive stomata

When the olive trees are dry, the stomatal closure is more common, although they can close them a few hours a day when they exceed 34 degrees, and they recover at cooler hours in the afternoon and in the morning, also with the contribution of water from rain unless the damage is very great.

In traditional irrigated olive trees, in intensive and super-intensive olive trees, the normal thing is that they have drip irrigation, a rigorous control of irrigation is enough to minimize the closure of stomata in heat waves and that the tree can continue its maximum development.

With our sensors we measure the soil water content and its control makes the stomata of the olive tree do not close and the tree, despite having temperatures above 34º, can maintain its balance and continue to carry out photosynthesis while continuing the biological process normal. Excess potassium is avoided, which increases the risk of closing the stomata and turning the leaves yellow.

Estoma cerrado
Closed stomata. 1-Epidermis. 2 and 5-Water. 3 and 6-Core. 4-Chloroplasts. 7- Potassium.

Other effects of water stress in the olive grove

The use of soil moisture, temperature and electrical conductivity sensors help to control the irrigation policy, to optimize the balanced development of the plantation.

[Productive period]

[Effects of water stress]

Olive tree growthThe number of branches and flowers is reduced and therefore the production
Flower budsDecrease the number of flowers
FloweringFertilization decreases
Fruit formationLoss of fruits
Fruit developmentDecrease the size
Greening or color changeColor alteration
Fruit ripeningSmall size. Less oil
Sensores en olivo intensivo - Control de humedad y de los estomas del olivo
Irrigation control in olive trees at different depths-Plantae Sensors
Receiver hub in intensive olive tree

Receiver hub in intensive olive tree


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