求问，已经凌乱了。。。。

zjz1304

Although heirloom tomatoes, grown from seeds saved during the previous year, appear less appetizing than most of their round and red supermarket cousins—they are often green and striped, or have plenty of bumps and bruises—heirlooms are more flavorful and thus in increasing demand.

其中的, grown from seeds saved during the previous year, 去掉这两个逗号可以吗？
是做定语修饰tomatoes吗？
为啥要加这两个逗号啊？
我感觉我基础语法已经混乱了，求人指导

abjure

, grown from seeds saved during the previous year, 做插入语， 在文章作为modifer起次要作用， 用逗号隔开是作者的主语和谓语的关系更加清晰。

zjz1304

经过几天的学习貌似能明白了，谢谢。