Handheld submerged plant sample collecting device

The utility model discloses a handheld submerged plant sample collecting device which comprises a holding cylinder, a limiting and rotating mechanism is arranged in the holding cylinder, the limiting and rotating mechanism comprises a rotating rod, a rotating handle, a connecting rod, a limiting shaft sleeve, a backing ring, a supporting spring, an extension rod and a push plate, the rotating rod is rotationally connected into the holding cylinder, and the connecting rod is connected with the rotating handle. A rotating rod is arranged in the holding cylinder, a rotating handle is connected to the position, corresponding to the top of the holding cylinder, of the top end of the rotating rod in a clamped mode, a connecting rod is connected to the bottom end of the rotating rod in a clamped mode, and a limiting shaft sleeve is movably connected to the position, corresponding to the interior of the holding cylinder, of the outer side of the connecting rod. The backing ring drives the limiting shaft sleeve to mov