imbued with the grayish sunlight of windy days 为过去分词短语作非限制性定语，修饰interludes。

赞同曹老师解答观点：

There was hardly any sign of life—not even a blade of grass—during these long interludes, imbued with the grayish sunlight of windy days.

imbued with the grayish sunlight of windy days 相当于非限制性定语从句 which was imbued with the grayish sunlight of windy days.

备注：which指代先行词interludes并在定语从句作主语。

【1】主动结构:imbue A with B 向A灌输B/使A充满B

【2】被动结构:A be imbued with B A被灌输了B/A被充满了B

Her voice was imbued with an unusual seriousness.

她的声音里充满着一种不寻常的严肃语气。

He was imbued with a desire for social justice.他满怀着寻求社会正义的愿望。

As you listen, you notice how every single word is imbued with a breathless sense of wonder.  

你仔细听,就会注意到每一个词都是那么的神奇，令人惊叹。

They are the men who can imbue their hearers with enthusiasm.  

他们使能够激发听众热情的人