A 'NanoSuit' successfully protects petals of cherry blossoms in high vacuum: examination of living plants in an FE-SEM.

Land plants have evolved on dry land and developed surface barriers to protect themselves from environmental stresses. We have previously reported that polymerization of a natural extracellular substance (ECS) on the outer surface of animals by electron beam or plasma irradiation, can give rise to a nano-scale layer, termed the "NanoSuit", which can keep small animals alive under the high vacuum of a scanning electron microscope (SEM). In the present research, we have focused on plants, using petals of cherry blossoms, as experimental specimens and examined their behavior under high vacuum conditions. Experiments on healthy living petals have demonstrated that without any pre-treatment, the overall morphology of specimens is well preserved and intact after imaging in an SEM, suggesting that natural substances on the petal surface behave like animal ECS and form a NanoSuit following irradiation with an electron beam. Furthermore, we have shown that the surface material can be extracted with chloroform and polymerized into a free-standing membrane by plasma irradiation. From our results, we conclude that surface materials, which have the ability to prevent water loss under natural conditions, increase the barrier ability and can protect plants under high vacuum conditions.