Influence of Mycorrhizal Fungi on Growth and Nutrient Uptake of Micropropagated Guava Plantlets (Psidium guajava L.) during Acclimatization and Plant Establishment

Abstract

The effect of mycorrhizal fungi on growth and nutrient uptake during acclimatization and plant establishment of micropropagated guava plantlets (Psidium guajava L. cv. Media China) was determined. Half of the plantlets were inoculated with the endomycorrhizae isolate ZAC-19 and grown in a glasshouse for 18 weeks. The isolate ZAC-19 was collected from the Chihuahuan Desert in Zacatecas State, Mexico, and is a mixed isolate containing Glomus etunicatum and unknown Glomus spp. Plantlets were fertilized with modified Long Ashton nutrient solution containing 11 μg P/ml. Shoot length, leaf area, leaf number, and dry mass partitioning were positively affected by mycorrhizae compared to noninoculated plantlets; however, noninoculated plantlets had greater leaf area ratios and specific leaf area. Mycorrhizal plantlets generally had increased leaf tissue mineral levels, particularly P, Mg, Cu, and Mo. However, noncolonized plantlets had higher N, K, and Mn. At the end of the experiment, roots of inoculated guava plantlets had colonization levels of 94.3%.