Eutrophication of lakes. Some lakes also demonstrate the reverse process (meiotrophication), becoming less nutrient rich with time. The main difference between natural and anthropogenic eutrophication is that the natural process is very slow, occurring on geological time scales. Eutrophication is a common phenomenon in coastal waters. In contrast to freshwater systems, nitrogen is more commonly the key limiting nutrient of marine waters; thus, nitrogen levels have greater importance to understanding eutrophication problems in salt water. Estuaries tend to be naturally eutrophic because land-derived nutrients are concentrated where run-off enters a confined channel. Upwelling in coastal systems also promotes increased productivity by
Epigenetics of plant growth and development premise in plants. In hybrids, lack of proper regulatory action, such as silencing by methylation, leads to uninhibited genes. If the gene is involved in growth, such as photosynthesis, the plant will experience increased vitality (Ni et al. 2008). The results heterosis can be seen in traits such as increased fruit yield, earlier ripening, and heat tolerance. Heterosis has been shown to provide increased general growth and fruit yield in tomato plants (Xiaodong). Epigenetics of plant growth and development Plants depend on epigenetic processes for proper function. Epigenetics has been defined as "the study of changes in gene function that