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The ATP molecules discovered in recent years as the traditional biological organisms energy metabolism currency and also the regulation of plant growth and development, and response to biological abiotic stresses. In this study, physiology, pharmacology and molecular biology experiments means, in order to identify ways to improve corn crop drought exogenous ATP concentration and time threshold clarify maize in response to water stress in the ATP signal H 2 O 2 , NO signal between the network and the extracellular ATP pretreatment to drought stress under plasma membrane aquaporins ZmPIP. gene expression system reveals extracellular ATP mediated signaling molecule of plant drought mechanism. The main findings are as follows: 1. Exogenous ATP pretreatment 4h, significantly increased under drought stress reactive oxygen O 2 - · H 2 O 2 of content, enzymatic defense system, SOD, CAT and APX activity, non-enzymatic defense system GSH and Vc content, soluble protein and free proline content, and makes the membrane lipid peroxidation product malondialdehyde content decreased significantly, the result of an increase in root hydraulic conductance, leaf water status remained stable moisture metabolically active. This characteristic has obvious concentration effect, i.e. the low concentration of the promotion, while high concentration is suppressed. In addition, ATP clear enzyme Apyrase be able to lift the exogenous ATP, extracellular ATP as a signaling molecule mediated drought resistance of corn plants. 2 DPI pretreatment significantly to reduce eATP induced drought the stress under maize leaves O 2 - · and H 2 O 2 content and antioxidant defense enzymes SOD, CAT and APX activity derived from NADPH oxidase the ROS is eATP mediated downstream signaling of maize drought resistance; increased Hb pretreatment significantly induced drought eATP Stress the maize leaves O 2 - · the H 2 O 2 content, but reduced antioxidant defense enzyme activity, suggesting NO is also eATP to the mediated downstream signaling of maize drought resistance. When blocking ROS Synthesis, EATP not induce the formation of NO, Clear NO No affect eATP induced ROS formation. The corn plant antioxidant Description mediated in eATP, thus drought signaling pathways, ROS in eATP downstream, NO is downstream of ROS. Outside source ATP pretreatment to drought stress under ZmPIP1; 2, ZmPIP2; 1 and ZmPIP2; 5 of expression are significantly significantly reduce, the contrary, inhibition of ROS or cleared of NO, are significant with increased under drought stress ZmPIP1; 2, ZmPIP2 ; 1 and ZmPIP2; 5 expression. The description eATP play regulate ZmPIP gene expression through its downstream signaling ROS and NO. And regulation of antioxidant defense is different, in regulating ZmPIP gene expression, there by EATP → of ROS → ZmPIP by eATP → NO → ZmPIP two parallel pathways.
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