Osmotic adjustment refers to various stresses, such as drought, low temperature, high temperature, and salting, that directly or indirectly cause water stress on plants. Underwater stress, some plants can actively accumulate various organic or inorganic substances to increase the concentration of cellular fluid , Reduce osmotic potential, improve the ability of cells to absorb or retain water, thereby adapting to water stress environments. Based on the above definitions, which of the following is options that are not osmotic? ['Elevated extracellular fluid osmotic pressure when drinking water is insufficient stimulates hypothalamic osmotic pressure receptors and produces thirst.', 'Limonium plants have increased leaf cell volume under salt stress, absorbed more water and reduced salt concentration.', 'Phalaenopsis under salt stress can absorb external salt and accumulate in the vacuole to absorb water.', 'The first response of maize plants to drought stress is to avoid low water potential through stomatal closure to reduce light energy capture.']