Study On The Mechanism Of Spore Release Of Typical Nematodontae Polytrichaceae Plants In Guizhou

The peristome is born at the mouth of the capsule of the moss plant,the dominant spore release important organ.However,the studies on the function of peristome at home and abroad are limited to the outer-vapourwind dispersal arthrodontae mosses,but not to the wind dispersal nematodontae Polytrichaceae plants.In order to investigate the effect of nematodontae peristome on spore dispersal and the mechanism of spore release in Polytrichaceae species.In this experiment,we select the Polytrichum commune Hedw,Pogonatum inflexum and Atrichum undulatum var.gracilisetum as the research object to design indoor simulation field wind blowing model to observe the changes of capsule structure and the release of spores by controlling humidity and wind speed.The main results are as follows:(1)When the humidity increase,the size of peristome structure and epiphragm enlarge significantly,the area of epiphragm increased by 20%on average,and the space between peristome broadens by 5.18 ?m.The peristome has no obvious spatial displacement,which is different from the hygroscopic movement of the arthrodontae mosses.Thus,we call it “subhygroscopic movement”.This movement plays a key role in spore release and can significantly increase the spore release of Polytrichaceae under the cooperative wind.(2)Based on the analysis of the internal structure of the capsule,it is inferred that the spores in the capsule can be divided into two parts: the free spores at the mouth of the capsule;and the internal stored spores of a capsule.The latter is inhibited by the special structure inside the capsule and cannot move to the mouth of the capsule,so that the plant cannot release a lot of spores when it is dry.When the humidity enhances,the structure of the capsule changes and the spores are replenished to the mouth,which can increase the quantity of the spores released.(3)According to the release quantity of spores,the proportion of cluster spores(C/T)and the proportion of small cluster spores in cluster spores(S/C)correlation in the cycle of Polytrichaceae.It is inferred that there are differences in the maturity of the spores in the capsule,which results in the differences in the conglutination between the spores.The immature spore with high adhesion formed cluster spores and were inhibited to release,while the mature loose spore released first.(4)The orientation of the mouth of the capsule and the length of the seta have a synergistic effect on the release level of the spores,and the orientation of the mouth of the capsule is the key factor.When the mouth of the capsule is downward,the length of the seta doesn't affect the release level of the spores.When the mouth of the capsule is upward,the loss of the seta can significantly reduce the release level of the spores.And the release of spores is higher when the mouth of capsule is downward than that when the mouth is upward.In this study,it was found that nematodontae peristome also exhibit hygroscopic movement and play an important role in the release of spores from Polytrichaceae plant.The regulation mechanism of spore release is also related to the internal structure of capsule and the mature state of spore.This mechanism ensures that the spores of Polytrichaceae can release a large number of mature spores when the environment humidity is suitable,which is of positive significance for the propagation of this species.