Physiological plant disorder diseases. Improving drainage will help to alleviate this problem. Hail can cause damage to soft skinned fruits, and may also allow brown rot or other fungi to penetrate the plant. Brown spot markings or lines on one side of a mature apple are indicative of a spring hailstorm. Plants affected by salt stress are able to take water from soil, due to an osmotic imbalance between soil and plant. Poor growth and a variety of disorders such as leaf discolouration (chlorosis) can be caused by a shortage of one or more plant nutrients. Poor plant uptake of a nutrient from
Plant to plant communication via mycorrhizal networks can transfer various infochemicals is that they have been show to transfer molecules such as lipids, carbohydrates and amino acids. Thus, transfer of infochemicals via mycorrhizal networks can act to influence plant behavior. There are three main types of infochemicals shown to act as response inducing signals or cues by plants in mycorrhizal networks, as evidenced by increased effects on plant behavior: allelochemicals, defensive chemicals and nutrients. Allelopathy is the process by which plants produce secondary metabolites known as allelochemicals, which can interfere with the development of other plants or organisms. Allelochemicals can affect nutrient uptake, photosynthesis and growth; furthermore,