ISHS Acta Horticulturae 773: XXVII International Horticultural Congress - IHC2006: International Symposium on Citrus and Other Tropical and Subtropical Fruit Crops
RESPONSES OF CITRUS SEEDLINGS AND A LEGUMINOUS HERB, STYLOSANTHES GRACILIS, TO ARBUSCULAR MYCORRHIZAL FUNGAL INOCULATION |
| Authors: | Q. Yao, F.X. Lin, J.Z. Chen, X.T. Lei, H.H. Zhu |
| Keywords: | arbuscular mycorrhiza fungi, growth response, morphology, orchard, organic agriculture, intercropping |
| Abstract:
Intercropping citrus trees with a leguminous herb, Stylosanthes gracilis, is widely practiced in organic production systems in southern China to improve the orchard soil and the productivity of citrus plants. Arbuscular mycorrhizal fungi (AMF) have been proposed as a potent biofertilizer in organic agriculture. For this purpose, the citrus seedlings and S. gracilis in monoculture were inoculated with AMF, Gigaspora margarita, in pot experiment to investigate the response of citrus seedlings to AMF inoculation. After harvest, the plant growth and morphological characteristics of citrus seedlings were analyzed. Mycorrhizal colonization was measured, and the plant biomass was recorded. Phosphorus (P) content was also determined. The contributions of AMF inoculation to plant biomass and P uptake were calculated. Results showed that mycorrhizal colonization of citrus and S. gracilis plants were 7.9 and 77.9%, respectively. Due to the low colonization, AMF inoculation did not increase but slightly decreased the biomass and P uptake of citrus seedlings, while both biomass and P uptake of S. gracilis were greatly promoted. The contributions of AMF inoculation to biomass and P uptake of citrus were -12.9 and -17.4%, respectively, in contrast with 71.0 and 80.7% for S. gracilis. These results suggested that the strain of G. margarita may increase the nutrient-competing capacity of S. gracilis, and hence is not a potential biofertilizer candidate in citrus-S. gracilis intercropping system. Results also revealed that AMF inoculation did not affect the total root length and root tip number of citrus seedlings, but increased significantly the leaf number and specific root length (cm/g). This may indicate the involvement of phytohormones other than mineral nutrients. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
