黄瓜种子低温收缩变形行为研究

Low Temperature Shrinkage Deformation Behavior of Cucumber Seeds

目的明确降温过程中黄瓜种子种皮和子叶的变形行为。方法搭建低温变形测试系统,在27℃至-18℃的降温过程中,利用数字图像相关(DigitalImage Correlation,DIC)方法,分别对黄瓜种子种皮和子叶的低温变形行为进行测试分析。结果在种子长轴和短轴方向,种皮平均压应变量恒大于子叶,长轴方向的平均压应变量大于短轴方向。在降温过程中,种皮2个方向的平均压应变量先增加,后趋于平稳;子叶2个方向的平均压应变量随温度降低逐渐增加。结论种皮和子叶的变形行为具有较大差异,低温保存时,由于两者收缩变形不协调,可能引起失配应力从而造成种子破坏。

The work aims to clarify the deformation behavior of cucumber seed coats and cotyledons during the cooling process.A low-temperature deformation test system was built.During the cooling process from 27℃to-18℃,the low-temperature deformation behavior of cucumber seed coats and cotyledons was analyzed through the digital image correlation(DIC)method.The results showed that the mean pressure strain of seed coats was constant greater than that of cotyledons in the direction of long axis and short axis,the average compressive strain in the long axis direction was greater than that in the short axis direction.During the cooling process,the average pressure strain of seed coats in both directions increased first,and then tended to be stable;The mean pressure strain in both directions of cotyledons increased gradually with the decrease of temperature.The deformation behaviors of seed coats and cotyledons are quite different.When stored at low temperature,the mismatch stress may be caused due to the incongruous shrinkage of seed coats and cotyledons,which may cause the seed damage.