Final answer:
Mycorrhizae enhance plant survival by extending root growth, thus improving water and nutrient absorption. This symbiotic relationship is vital for plant health in poor soil conditions and defense against pathogens.
Step-by-step explanation:
The question, “How would the mycorrhizae increase the plants’ survival compared to plants without mycorrhizae?” touches on the ecological benefits of mycorrhizal relationships. Mycorrhizae significantly improve a plant’s ability to absorb water and nutrients, particularly phosphorus, through extensive networks of fungal hyphae that enlarge the root surface area. Additionally, these fungi assist in the uptake of micronutrients like zinc and copper and enhance the plant’s resistance to pathogens by forming a physical barrier and potentially producing antibiotic compounds. This symbiotic relationship is particularly beneficial in poor soils, where nutrients are limited. The fungi, in return, receive up to 20 percent of the carbon produced through the plant’s photosynthesis.
Given the options provided, the most accurate answer to how mycorrhizae increase a plant's survival is (a) Mycorrhizae enhance root growth, increasing water and nutrient absorption. While mycorrhizae do indeed help in plant defense mechanisms against pathogens, the primary reason for increased survival is due to the enhanced nutrient and water uptake capabilities the fungi provide. This increase in survival can be crucial in arid or nutrient-poor environments, making the association between plants and mycorrhizae crucial for reclamation and agriculture.