by Matt Hagny, consulting agronomist for no-till systems since ‘94.

The first plant part to emerge from a germinating seed is a root, called the radicle (not radical) in both dicots (‘broadleaf’ plants) and monocots (grasses). The radicle helps the seed continue to pull in moisture from a larger volume of soil, as well as nutrients for growth. Ideally the radicle grows downward, not laterally along the furrow, and this is especially important for dicots (broadleaves). The radicle will not grow upward, since plants are responsive to both sunlight and gravity, which is communicated among plant parts via hormones. However, for a seed that is ‘upside down,’ the radicle will have to curve around the seed to begin its downward path.

This very early path of the radicle is far more crucial for dicots (broadleaf species) than monocots (grasses). Examples of broadleaf species include sunflowers, soybeans, cotton, canola & other brassicas, all peas & beans, alfalfa, clover, flax, deciduous trees, and so on. It isn’t really about the size of the leaf, instead it’s the shape of the leaves, and more definitively whether the first set of leaves coming from the seed are a pair (hence dicot, ‘di’ meaning two) or a single leaf (monocot). Corn (maize) has big leaves, but it is a monocot or grass. So is milo (sorghum), and of course…continue reading here: plant-roots