Cactus: Its peduncle stoma appears in nightly meeting open position, can release an oxygen, absorb the harmful to human body gas in air, carry its a department, absorb use, purify air.

• 仙人掌：它的肉茎气孔在夜间会呈现张开状态，能释放出氧气，并吸收空气中对人体有害的气体，将其输送到根部，吸收利用，净化空气。