Effects of arbuscular mycorrhiza and irrigation frequencies on nutrient uptake and growth parameters of Pelargonium reniforme Curtis

Abstract

Mycorrhiza inoculation is known to be beneficial for nutrient uptake in providing a symbiotic association with plant roots. Similarly, irrigation can affect plant growth parameters. The combination and availability of both can enhance plant quality for commercial purposes. Pelargonium reniforme Curtis is an indigenous herbaceous groundcover from the Western Cape region of South Africa. This species is drought resistant and offers great economic potential as a colourful ornamental plant. This study aimed to measure the effects of different irrigation intervals with and without arbuscular mycorrhiza on plant growth, leaf chlorophyll content and nutrient uptake of P. reniforme. Plants were grown in pots and irrigated via drip irrigation system over a period of 15 weeks with a total of ten treatments applied in ten replicates. Irrigation was supplied at 320 mL of water per pot at five different irrigation intervals changing from once a day to every 24 days. Half of the treatments were inoculated with 30 g of arbuscular mycorrhiza (xM+) and compared with the ones without arbuscular mycorrhiza (xM-). Results of the irrigation intervals showed statistical significance in all variables except the fresh root weight. A significant difference was observed in the mycorrhiza inoculation in the total fresh weight. Results on measurements of C, K, Mg, N and P were all significant in the irrigation interval treatments without mycorrhiza. There was also a higher interaction between the irrigation interval and mycorrhiza in terms of the availability of Mg. Total dry weight and chlorophyll contents were the highest in the most frequent irrigation of P. reniforme. Additionally, arbuscular mycorrhiza generally increased the growth parameters, photosynthesis and water assimilation in the species.