Study On Movement Characteristics Of Sporangium Of Pteridophytes

Pteridophytes,as an early plant group adapted to the terrestrial ecological environment,have made important contributions to the establishment and improvement of the terrestrial ecological environment.Sporangium is one of the evolutionary characteristics of ferns adapted to terrestrial life.Some studies have shown that the spores of ferns have strong long-distance transmission ability,while the transmission of spores mainly depends on the movement of sporangium.while the transmission of spores mainly depends on the movement of sporangium.Sporangium is the carrier of spores and provides protection for spores when they are immature.Sporangium has important significance for the reproduction of ferns.So far,the research on the phenomenon of sporangium movement is mostly limited to a complete ejection process,the research content is relatively single,no new type of sporangium movement has been found,and most of them are only observed for a certain family,the scope is relatively limited,and there is a lack of systematic comparison between different groups and different families and genera.At the same time,the movement of sporangium should be supported by structural features,and the literature shows that some stable anatomical features are an important basis for systematic classification.Therefore,this experiment studied and observed the sporangium movement and anatomical characteristics of 32 species of Pteridophytes in 19 families,of which 21 species of Pteridophytes in 17 families compared and observed the sporangium movement phenomenon by video recording.In order to avoid the interference of air flow,a sporangium ejection distance measuring device was made in the room with temperature of 24-28°C and air humidity of 50-60% to measure the ejection distance and reveal the movement characteristics of Pteridophyte sporangium;Among them,18 species of Pteridophytes in 13 families were observed by paraffin section,and the developmental process and mature anatomical characteristics of sporangia were compared to explore the relationship between the movement phenomenon of sporangia and its structure;Using R software to explore the correlation between sporangium movement characteristics and habitat,altitude and flora,the research results are as follows:(1)The movement types of sporangium can be divided into three types: simple cracking movement;clamshell opening and closing movement;annulus ejection movement.(2)The sporangium of lsoetaceae and Salviniaceae do not have dehiscence structure and no movement.After the sporangium of Equisetaceae cracks,the inner spores have a unique elastic filament movement,which is sensitive to the humidity of the air and can exhibit a regular dry and wet movement phenomenon with changes in air humidity.(3)According to the position and quantity of sporangium implantation,spore type,whether there is movement of sporangium,whether spores in sporangium have no elastic filaments,time from sporangium cracking to movement completion,whether there is Y-shaped thickening of annulus cells,sporangium size,annulus type,habitat type,ejection distance,time interval between multiple ejection,whether there is special movement,special movement type(such as sporangium breaking away Deployment blocked,rebound blocked,torsion ejection,swing cracking,sporangium ejection,ring cracking only,single side sac wall folding,spores ejected during sac wall deployment,spore quantity,sporangium movement type such as simple cracking movement,clam opening and closing movement,ring ejection movement,maximum cracking angle,maximum ejection(opening and closing)times,capsule wall state after the movement,capsule wall layers 30 features such as U-shaped thickening of annulus cells were listed in combination with PPG I system,and traceable features were found for the molecular classification system represented by PPG I from the perspective of sporangium movement and structure.(4)The correlations between the six characteristics of sporangium movement type,ejection distance,ejection(opening and closing)times,whether there is special movement phenomenon,maximum unfolding angle and movement time and altitude,flora and habitat were discussed;The ejection distance is related to the fauna;Whether there is a special movement phenomenon is related to the flora;The maximum unfolding angle and movement time are related to altitude.(5)The relationship between sporangium movement and structure was discussed based on anatomical characteristics,emphasizing the importance of annulus structure for sporangium movement.