以数量为基准的橡胶粒子粒径多样性及年度变化研究

Particle Size Diversity and Annual Variation of Rubber Particle Based on Quantity

橡胶粒子是胶乳中的重要组分,对胶乳稳定性、橡胶生物合成和加工性能等方面具有重要影响,但橡胶粒子的大小和分布在不同种质间的差异及其年变化尚无系统研究。本研究以国家橡胶种质资源圃种植的486份巴西橡胶野生种和栽培种为研究对象,于2020—2021年割胶期间每月采割胶乳,应用激光散射粒度分布分析仪,对橡胶粒子平均径(Da)、中径(Di)、中径/平均径(Di/Da)、粒径≤0.259μm的橡胶粒子频度、粒径≤0.197μm的橡胶粒子频度进行分析研究。结果表明:(1)不同种质Da范围为0.313~0.439μm,变异系数为0.008~0.206;Di范围为0.209~0.366μm,变异系数为0.009~0.235;Di/Da为58.3%~84.9%,变异系数为0.015~0.123;粒径≤0.259μm的橡胶粒子频度范围为31.1%~61.8%,变异系数为0.013~0.322;粒径≤0.197μm的橡胶粒子频度范围为17.6%~46.4%,变异系数为0.018~0.588,且5项指标在不同种质间均达到极显著差异,适宜作为胶乳特性指标。(2)对5项指标进行相关性分析表明,Di与Da的相关系数为0.781;粒径≤0.259μm的橡胶粒子频度与粒径≤0.197μm的橡胶粒子频度的相关系数为0.976;相比Da,Di与Di/Da的相关性更大,相关系数达0.814;相比Da,Di与粒径≤0.259μm的橡胶粒子频度和粒径≤0.197μm的橡胶粒子频度也更为相关,相关系数分别为-0.520和-0.632,表明Di具有更强的统计学意义。(3)对Da、Di、Di/Da指标年变化研究结果表明,各月份间存在一定差异,Da在6—8月、10月、12月差异不显著,9月和11月稍低于其他月份;Di在6—9月、11月、12月间差异不显著,10月份稍低于其他月份;Di/Da在6月、8月和9月之间差异不显著,11月和12月上升,7月和10月明显下降。(4)Da、Di、Di/Da、粒径≤0.259μm的橡胶粒子频度、粒径≤0.197μm的橡胶粒子频度各月的测定值与年平均值均呈显著相关,隔月测定3次(6月、8月、10月,7月、9月、11月,8月、10月、12月)与全年平均值相关系数均达0.850以上,可供未来橡胶粒子粒径测试采用。

Rubber particles are important components in latex,and have important effects on latex stability,rubber biosynthesis and processing properties.However,the difference of rubber particle size and distribution among different germplasms and the annual changes have not been systematically studied.In this study,486 wild and cultivated Hevea germplasm planted in National Rubber Germplasm Respository were selected,and the latex were collected monthly during the tapping period from 2020 to 2021.The average diameter(Da),intermediate diameter(Di),intermediate diameter/average diameter(Di/Da),particle size≤0.259μm frequency and particle size≤0.197μm frequency of rubber particles were analyzed and studied.Da varied from 0.313μm to 0.439μm,and the coefficient of variation(CV)was 0.008-0.206.Di varied 0.209-0.366μm,and the CV was 0.009-0.235.Di/Da varied 58.3%-84.9%,and the CV was 0.015-0.123.particle size≤0.259μm frequency varied 31.1%-61.8%,and the CV was 0.013-0.322;particle size≤0.197μm frequency varied 17.6%-46.4%,and the CV was 0.018-0.588.The five indexes showed significant differences among germplasm,which were suitable to be latex characteristic index.The correlation analysis of the five indexes showed that the correlation coefficient of Di and Da was 0.781;The correlation coefficient of particle size≤0.259μm frequency and particle size≤0.197μm frequency was 0.976;The correlation between Di and Di/Da was higher than that of Da,and the correlation coefficient reached 0.814.Di was also more correlated with particle size≤0.259μm fre-quency and particle size≤0.197μm frequency than Da,and the correlation coefficient reached-0.520 and-0.632,in-dicating that Di had a stronger statistical significance.Annual changes of Da,Di and Di/Da showed some difference.Da in June,July,August,October and December was not significant,and September and November were lower than other months.Di was not significantly different in June,July,August,September,November and December,and just a little lower in October.Di/Da had no significant difference in June,August and September,increased in November and De-cember,but declined obviously in July and October.Da,Di,Di/Da,≤0.259μm frequency,≤0.197μm frequency in each month were all significantly correlated with the annual average.However,correlation coefficient were higher between alternate monthly measurements(June,August,October;July,September,November;August,October,December)and the annual average,reaching more than 0.850.That can be used for future rubber particle size testing.