What are the consequences of poor gas exchange in the growing medium inside an orchid pot?

Whether the oxygen content in the medium is moderate affects orchid root growth and the normal development of stems and leaves, and there is a positive correlation. When the oxygen content in the medium is insufficient, the content of carbon dioxide and other gases rises substantially, and the root system's respiration, water absorption, nutrient absorption and transport capacity and so on are also restricted. The medium's pores are heavily occupied by water, so fresh oxygen cannot enter the pores; because the roots are subject to oxidation by microorganisms and chemical reactions, large amounts of oxygen are consumed, and root growth is then severely hindered. In addition, because of insufficient oxygen, organic matter and inorganic substances cannot undergo complete oxidation, and produce toxic substances such as organic acids, hydrogen sulfide and so on, which poison the root system and cause it to lose normal physiological function. When the oxygen diffusion rate inside the orchid pot is poor, the life of beneficial microorganisms such as orchid mycorrhizal fungi, nitrifying bacteria, mycorrhizal fungi, phosphate-solubilizing bacteria, cellulose-decomposing bacteria and so on is also restricted, and they cannot decompose and release their intermediate products for the root system to absorb and use, so as to stimulate the root system to continue elongating and perform its proper functions; this affects the ability of the Chinese orchid plant to move and store water and nutrients, reduces the root cells' uptake of the nutrients and water they need, and the orchid plant's growth shows wilting and stunted, small stature. Generally, whether the medium's aeration is good has a causal relationship with the particle size of the medium material and with water management. The larger the particles of the medium material, the better the aeration; the better the aeration, the more it helps oxygen diffusion, so that the root system obtains more oxygen. However, medium materials with large particles are less able to retain water, and under high summer temperatures they lose water faster, which very easily causes the new roots to lack water and stop growing. The particle stability of the medium material also affects aeration; for example, the inorganic medium vermiculite has relatively low particle stability and easily disintegrates into fine particles, occupying the pores in the medium, making aeration worse, and causing the root system to become oxygen-deficient and rot, so that growth and development deteriorate.