Bamboo has solar terms and modesty.

1, the old saying goes, "Before bamboo is unearthed, there is a knot, and Lingyun will always be open-minded." Bamboo has knots before it is unearthed, but the more it reaches the air, the more hollow it becomes, which shows that bamboo is modest and open-minded;

2. Bamboo is open-minded, because its interior is hollow, so that food can be put in a hollow bowl, hollow bamboo can grow, and "hollow" people can gain knowledge. Here, hollow means open-minded.