External fertilization occurs when gametes are expelled into a watery substrate from the parental bodies before fusion; it is typical of sporebearing plants.
当配子在融合之前从亲本体中排出到有水介质时发生体外受精，这是孢子植物的特征。
2
Compared with gymnospermae pollen, the fern spore has a more closer relationship with soluble organism in the low-rank source rocks from the coal-bearing strata.
而蕨类孢子和裸子植物花粉相比，可能对低熟-未熟油，特别是含非烃较高的低熟油有某种更为密切的联系。
3
Moreover, host plant can also affect the growth and development of AM fungi, and produce different infection rate, spore-bearing rate and mycorrhiza effect.