Nature’s 360 Million Years Old Miracle

About 360 million years ago, seed plants began to appear. Before that many land plants used spores to reproduce. Spores have to survive without built-in nutrition or physical protection. Seeds are nature’s way of making sure that plant embryos didn’t dry out and had some energy to start growth. Thus, encased sometimes in a very tiny shell is the plant’s instruction manual awaiting the right amount of water, proper temperature and location. Some seeds, like the mullein, can wait over a 100 years for this to happen. If it is lucky enough to have landed somewhere that meets all three requirements, it will start to grow, called germination. The food supplies stored within the seed provide the energy. First a root will appear pushing downward into the soil to anchor the new plant and provide it with water and minerals necessary for growth. It is the tiny microscopic root hairs that actually do the work (white fuzzies). At the same time or just a little later, a stem will appear pushing its way up through the soil towards the sunlight. Sometimes baby leaves will be on the stem (green). These are called cotyledon or “seed leaf” and are present in the seed prior to germination. They will be the first leaves of the plant. By having these embryonic leaves, the plant will be able to produce food (photosynthesis) soon after the stem has emerged from the soil. This requires less food to be stored in the seed itself. Frequently cotyledons appear different than any future leaf on the plant. Once the stem or shoot appears above the ground it is called a seedling and germination has ended. Now the seed has done its job of providing instructions, energy and protection. If the plant continues to get the right amount of water, sunlight and nutrients, growth will be successful and it will produce its own seeds -insuring the cycle will begin again. (Photo of bean germination www.visions-of-science.co.uk)