种子萌发后,胚芽向上生长形成作物的茎。茎把根、叶、花、果实等各部分连接在一起,支撑着整个作物体。根系从土壤中吸收来的水分和养料,以及根系合成的许多有机物质,都通过茎输送到地上部分。叶子在阳光下制造的有机物质也通过茎输送给根系及其他部分。因此,茎是作物体内物质交流的通道。 After germination, the germ grows up to form the stem of the crop. Stems, roots, leaves, flowers, fruits and other parts connected together, supporting the entire crop. The roots absorb moisture and nutrients from the soil, as well as many of the organic substances that the roots synthesize, and are transported to the aerial parts by the stems. The organic matter that foliage makes in the sun is also delivered to the roots and other parts through the stems. Therefore, the stem is the channel for the exchange of matter in the crop.