Root hairs are narrower than roots. A root is usually at least __________________ mm in diameter, but root hairs are only approximately ___________________ _____ mm in diameter. Look at Figure 7-9. Could either roots or root hairs enter the pores represented by the red part of the chart? Could either or both enter the gray part? The white part? Most roots grow near the soil surface, in the upper 20 cm, where most of the soil pores are between 0.2 to 60 mm wide. If a root did not produce any root hairs at all, could the plant obtain water and minerals from these abundant, narrow pores?

Figure 7-9

Transcribed Image Text:

Soil depth (cm) 0 10 Pores as % of total soil volume 20 30 40 20cm deep 40 cm deep 60 cm deep 80 cm deep Pore width less than 0.2 μm Pore width 0.2-60 μm Pore width greater than 60 μm Solid portion of soil 50 60