Effects of mycorrhiza colonization on growth, root exudates, antioxidant activity and photosynthesis trait of cucumber grown in Johnson modified nutrient solution

ABSTRACT

Mycorrhiza can improve plant growth and increase nutrient uptake. This study was conducted as factorial experiment based on complete random design (CRD) to study effects of mycorrhiza inoculation under limited iron (Fe) condition on antioxidant activity, phenol content and photosynthesis trait of cucumber (Cucumis sativus cv. N3). Treatments were Johnson modified nutrient solution (MNS) with 25% Fe (MNS1) = 0.57 mg/L Fe, 50% (MNS2) = 1.14 mg/L Fe and 100% (MNS3) = 2.3 mg/L Fe and mycorrhiza inoculation (M+) and non-mycorrhiza inoculation (M−) with 3 replications under hydroponic conditions. The results showed that plant growth and shoot phenol content decreased in the MNS1 treatment; whereas phenol content of the root exudates and antioxidant activity significantly increased in this treatment. All photosynthesis attribute increased in the MNS3 treatment. Mycorrhiza inoculation increased plant growth, phenol content, antioxidant activity and photosynthesis trait of cucumber. Also, mycorrhiza inoculation enhanced SPAD value in the MNS2 treatment and photosynthesis rate, transpiration and mesophyll conductance in all the modified nutrient solutions. Moreover, mycorrhiza symbiosis was stimulated by the internal carbon dioxide (CO₂) content of the stomata in the MNS2 and MNS3 treatments. Furthermore, Mycorrhiza inoculation improved phenol content of the shoots and roots in all the nutrient solutions, whereas antioxidant activity was affected by mycorrhiza inoculation only in the MNS2 treatment.

KEYWORDS:

• Mycorrhiza
• iron
• photosynthesis rate
• antioxidant activity