Nourished by their imported supply of nutrients,the young plants push out their roots and establish their place in the sun.

尤其是句中“imported supply”是指“进口的供给”吗，即指被吸收的外部营养。还是自身的内部营养，非来自外部吸收。

　　整段来自托福TPO，所问句为该段落最后一句，内容如下：

　　Plants with large, buoyant seeds—likecoconuts—drift on ocean currents and are washed up on the shores. Remarkablyresistant to the vicissitudes of ocean travel, they can surviveprolonged immersion in saltwater when they come to rest on warm beaches and theconditions are favorable, the seed coats soften.       Nourished by theirimported supply of nutrients, the young plants push out their roots and establish their place in the sun.

　　官方给的翻译为：

　　一 些拥有硕大的、可以浮于水面的种子的植物，像椰子，随洋流飘荡，被冲上海岸。对洋流变动抵抗的耐久性使得他们可以在海水的长期浸泡中生存下来。当他们停歇 在温暖的海滩上，一旦条件合适，种子的外皮就开始变软。    由于受到内部携带的营养物质的滋养，幼小的植物伸长出他们的根部，并开始在阳光下成长。

　　所以理解有矛盾