| Pteria penguin is the main shellfish species for producing shell pearl,and has good development potential.P.penguin lives on rocks,corals and other external substrates by means of byssus,which are strong and tough fiber bundles mainly composed of byssus.In order to understand the effect of large byssus on pearl breeding of P.penguin,the secretion process of byssus of P.penguin was recorded and observed.At the same time,paraffin section of P.penguin foot was made by using histological research method.The microstructure of P.penguin foot without byssus and P.penguin foot with byssus was com-pared and analyzed.The results showed that there was no obvious atrophy of endocri-ne glands and no large cavity in the foot of Pteria penguin;There was no significant differen-ce in the microstructure of the feet between the two species;It is considered that the byssus secretion of P.penguin is a very import-ant physiological process for both P.penguin with and without byssus.When the existing conditions of P.penguin are not suitable for byssus secretion,P.penguin will suspend byssus secretion,and when the byssus secretion conditions are mature,it will resecrete byssus.At the same time,this experiment explored the changes of byssus secretion of P.penguin under different environmental factors.There was no significant difference in the amount of byssus secretion between differ-ent groups(P > 0.05);There was no significant difference in the distal diameter,middle diameter and proximal diameter of P.penguin between different groups(P > 0.05).There was no significant change in the mechanical properties of the byssus,and there was no significant difference in the breaking force when the byssus were broken(P > 0.05).In addition,under different light cycle conditions,when the light intensity is 3000 Lux,it will inhibit the secretion of P.penguin,and P.penguin will stop the secretion of P.penguin.Under different p H water environment conditions,there was no significant difference(P > 0.05)in the amount of byssus secretion between P.penguin kept in p H = 7.5 water environment and P.penguin kept in p H = 8.1 water environment,but there was significant difference in the distal diameter of byssus(P < 0.05),and there was no signifycant differr-ence in the middle diameter and proximal diameter(P > 0.05),There was no significant difference between the two groups(P > 0.05).However,under different p H water environ-ment,the stiffness coefficient of byssus was significantly different(P < 0.05),and byssus was not a linear elastic material.These results indicated that the increase of water acidity had no significant effect on the secretion of P.penguin byssus,but the unit length of the byssus decreased.There was no significant difference in the amount of byssus secretion,byssus break-ing force,distal diameter,middle diameter and proximal diameter between P.penguin(P >0.05).The results showed that there were significant differences between 35 salinity group(control group),40 salinity group and 30 salinity group(P < 0.05).There was significant difference in stiffness coefficient among 40 salinity group,35 salinity group and 30 salinity group(P < 0.05).These results showed that the amount of byssuses secret-ed by P.penguin was more,the breaking force needed to break byssuses was greater,the diameter of byssuses was larger,and the secretion behavior of byssuses was more vigoro-us when the salinity was 35.However,under 40 salinity,the tensile length per unit length of the byssus increases with the same breaking force.The results showed that there were significant differences in the total number,break-ing force,diameter and stiffness coefficient of the byssus between P.penguin kept at 31℃and P.penguin kept at 21℃ and 27℃ under different water tempe-rature for 72 h(P <0.05).The results showed that in a certain temperature range,the activity of byssus secret-ion was not affected by temperature(21～27℃);The stiffness coefficient of foot wire is low,and it does not belong to linear elastic material.Compared with the other two groups,the breaking force required for byssus breaking was lower at 31℃ water tempera-ture,and the tensile length per unit length of byssus increased at the same breaking force. |
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