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Mycorrhizae are a powerful tool in sustainable agriculture, helping plants absorb more water and nutrients and better tolerate different types of environmental stress. However, the effectiveness of mycorrhizae can vary depending on the type of crop and the specific type of mycorrhiza. This article explores what mycorrhizae are, the types that exist, and which crops benefit the most from them, as well as those where they may not be suitable.
What Are Mycorrhizae?
Mycorrhizae are mutualistic symbiotic associations between fungi and plant roots. In this relationship, the fungi colonize the roots and help the plant absorb soil nutrients, primarily phosphorus, while the plant provides the fungi with carbohydrates and other organic compounds produced through photosynthesis.
Types of Mycorrhizae
There are mainly two types of mycorrhizae:
- Ectomycorrhizae (ECM): form an external network around the roots and penetrate the space between root cells but not inside them. They are common in trees and shrubs of forested areas.
- Endomycorrhizae (Arbuscular Mycorrhizae, AM): penetrate inside root cells, forming structures called arbuscules and vesicles. They are the most common mycorrhizae and are found in more than 90% of plant species.
Mycorrhizae and Crop Types
Crops That Benefit from Endomycorrhizae (Arbuscular Mycorrhizae)
Arbuscular mycorrhizae are suitable for most agricultural crops, including:
● Cereals: corn, wheat, rice, barley, oats.
● Legumes: chickpeas, alfalfa, soybeans, lentils.
● Vegetables: solanaceous (tomato, pepper), cucurbits (watermelon, zucchini), some leafy vegetables (mainly lettuce), alliaceous (garlic, onion).
● Fruit Trees: Stone fruits (peach, cherry), pome fruits (pear, apple), citrus (lemon, orange), nuts (almond, pistachio).
● Tubers: potatoes, sweet potatoes.
● Tropical Fruits: mango, avocado, pineapple.
● Herbs, Spices, and Oilseeds: basil, mint, sunflower, lavender, and aromatic plants.
These plants often show significant improvements in phosphorus and other nutrient uptake, as well as greater resistance to diseases and water stress when associated with arbuscular mycorrhizae.
Crops That Benefit from Ectomycorrhizae
Ectomycorrhizae are more specific and are primarily found in trees from forested areas, such as:
● Conifers: pines, firs, spruces.
● Temperate Forest Trees: oaks, holm oaks, beeches, birches.
● Temperate Climate Fruit Trees: walnuts, chestnuts.
These plants benefit from ectomycorrhizal relationships through greater nutrient absorption and resistance to environmental stress conditions.
Crops That Do Not Benefit from Mycorrhizae
Some plants do not form mycorrhizal associations or show no significant benefits. Examples include:
● Non-Mycorrhizal Plants: Some plant families, such as Brassicaceae (broccoli, cauliflower, mustard), Apiaceae (celery, cilantro), and Chenopodiaceae (beet, spinach), generally do not form mycorrhizae. These plants have developed other strategies to absorb nutrients without the help of mycorrhizae.
● Crops in Highly Fertile Soils: In soils that already have a high nutrient availability, especially with very high levels of phosphorus, the benefit of mycorrhizae may be minimal. In such cases, plants may not rely heavily on mycorrhizae for nutrition.
Conclusion
Mycorrhizae are a valuable tool in agriculture, improving nutrient absorption and stress resistance in a wide variety of crops. However, their effectiveness varies depending on the type of mycorrhiza and the specific crop. Arbuscular mycorrhizae are suitable for most agricultural crops, while ectomycorrhizae primarily benefit temperate forest trees. Some plants, especially those from the Brassicaceae (also known as crucifers), Apiaceae, and Chenopodiaceae families, do not form mycorrhizal associations and do not benefit from them. Understanding these differences is crucial to optimizing the use of mycorrhizae in agriculture and maximizing their benefits.
Agricultural Engineer and Product Technician