柑桔类果树,自生根和砧木的根系一般很少或不具根毛。柑桔在生长过程中,它的根系大量吸收附近土壤中的磷素,又加之磷在土壤中扩散系数很低,这样柑桔根系周围形成“无磷圈”,它对柑桔的生长十分不利。当柑桔根际接种菌根真菌时,则菌根真菌与柑桔的根系结合成相互有利的共生体——内生菌根。菌根真菌一方面从寄主吸收碳氢化合物作为营养的来源;另一方面它的菌丝从寄主根部扩散到柑桔根系的“无磷圈’外土壤中,从土壤中吸收大量磷素供柑桔生长的需要。美国和南非等国,把菌根真菌作为一种“生物肥料”已经在生产上广泛地应用。现在他们不但把菌根用于育苗营林,而且发展到进一步研究选择优良菌种,同时探索菌根与植株的生态学关系,以及菌根的生理机制的研究,菌根的制剂已逐步商品化。 Citrus fruit trees, rooted and rootstocks generally have few or no root hairs. Citrus in the growth process, its roots absorb large amounts of phosphorus in the nearby soil, coupled with phosphorus in the soil diffusion coefficient is very low, so that citrus root around the formation of “phosphorus-free ring”, which is very unfavorable to the growth of citrus . When citrus rhizosphere inoculated mycorrhizal fungi, mycorrhizal fungi and citrus root system combined into a mutually beneficial symbiont - endomycorrhizal. Mycorrhizal fungi on the one hand, from the host to absorb hydrocarbons as a source of nutrition; the other hand, its mycelium spread from the root of the root to the roots of citrus “non-phosphorus ring” outside the soil, from the soil to absorb large amounts of phosphorus for citrus Growing needs of the United States and the United States and South Africa and other countries, the mycorrhizal fungi as a “biological fertilizer” has been widely used in the production of now they not only the mycorrhizal nursery forest, but also to further study to select good bacteria At the same time to explore the ecological relationship between mycorrhiza and plants, as well as the physiological mechanism of mycorrhizal research, mycorrhizal preparations have been gradually commercialized.