Effects Of Arbuscular Mycorrhizal Fungi On Growth And Temperature Tolerance Of Rosa Hybrid And Chrysanthemum Morifolium

Arbuscular mycorrhizal fungi (AMF) have been shown to improve mineral nutrition, promote growth and development of host plants. AMF also can mitigate drought, salinity, temperature stresses, and improve the ability of pest and disease resistance. Rosa hybrid and chrysanthemum morifolium are most important cut flowers in the world. Temperature is an important environmental factor, which restricts a series of biochemical metabolism. High and low temperature stresses can cause great damage on the growth and development of Rosa hybrid and chrysanthemum morifolium.This experiments were carried out to examine the effects of different AMF strains on the growth of Rosa hybrida 'Carola' and Chrysanthemum morifolium 'Jinba'. AMF strains are Glomus diuphauam, G.etunicatum, G.intraradices, G.mosseae, G.versiforme. By measuring some morphological and physiological indicators, we screened out the best AMF strains for the growth of Rosa hybrid and chrysanthemum morifolium. On this basis, we have furtherly explored the effects and physiological mechanism of AMF on the high and low temperature tolerance of Rosa hybrid and chrysanthemum morifolium under high temperature (day 35℃/ night 28℃) and low temperature (day 10℃/ night 5℃) stresses, at the same time, setting normal temperature control (day 25℃/ night 18℃). The main contents and results in this study are as follows:1.Under normal temperature conditions, the treatments inoculated with five kinds of AMF could increase the plant height, stem diameter, leaf number, leaf areas, root length, and petal areas, thus significantly promote plant growth. The five kinds of AMF strains could enhance root activity, increase soluble sugar content, decrease malondialdehyde (MDA) content, and thus improve plant osmotic adjustment, alleviate membrane permeability and lipid peroxidation. The five kinds of AMF strains could also promote mineral nutrient absorption, increase N, P, K content. Moreover, The five kinds of AMF strains could strengthen the activity of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and other antioxidant enzymes in roots, leaves and petals, increase the ability of scavenging oxygen free radicals.2.As a result, AMF treatments could increase the growth of Rosa hybrid and Chrysanthemum morifolium. By comprehensive comparison, G.diuphauam and G.etunicatum were screened out as the best strains for Rosa hybrida. G.intraradlces is the best strain for chrysanthemum morifolium.3.Under high and low temperature stress, compared with non-AMF treatment, plant height, root length, leaf numbers, biomass production, and N, P, K content are significantly elevated in Rosa hybrid and chrysanthemum morifolium inoculated with AMF. The treatments inoculated with AMF could significantly inhibite the increasing of relative electric conductivity and MDA content, alleviate the oxidative damage by membrane lipid peroxidation, also could gradually increase the soluble sugar content and nitrate reductase (NR) activity.4.Under temperature stress, AMF is capable of significantly improving antioxidant enzyme activity, such as SOD, POD, CAT, ascorbate peroxidase (APX), and glutathione reductase (GR). Moreover, AMF could promote the ascorbic acid-glutathione system (AsA-GSH) cycle, significantly increase AsA, GSH contents and the AsA/DHA, GSH/GSSG ratio, enhance the resistance to oxidation stress, significantly alleviate the damage by high and low temperature stresses. Thereby, AMF could greatly enhance the high and low temperature tolerance of Rosa hybrid and chrysanthemum morifolium.This study pointed out the ability of AMF to alleviate the high and low temperature stresses for Rosa hybrid and chrysanthemum morifolium, probably was resulted from lowering reactive oxygen concentrations, alleviating cell membrane damage, increasing the antioxidant enzyme activity, ASA, GSH contents and the accumulation of osmotic adjustment compounds. Our results showed that AMF could be applied to production practice of the Rosa hybrid and chrysanthemum morifolium. The results could provide a solid theoretical foundation and practical significance for the applings.