Postharvest Biology and Technology 33 (2004) 255–262 Visualization of 3-D network of gas-ﬁlled intercellular spaces in cucumber fruit after harvest  Shinichiro Kuroki a,∗ , Seiichi Oshita a , Itaru Sotome a , Yoshinori Kawagoe a , Yasuhisa Seo b a Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan b College of Bioresource Sciences, Nihon University, Kameino 1866, Fujisawa, Kanagawa 252-8510, Japan Received 17 October 2003; accepted 4 April 2004 Abstract Gas-ﬁlled intercellular spaces are the predominant pathways for gas diffusion through plant organs and as such, are greatly related to the characteristics of gas exchange. However, their detailed structure is still unclear. In this study, X-ray computer microtomography (X-ray CT) was applied to the investigation of a three-dimensional (3-D) network of gas-ﬁlled intercellular spaces in the sarcocarp of cucumber fruit stored at 20 ◦ C. The attained spatial resolution was 2.48 m. Results showed that X-ray CT enabled the observation of gas-ﬁlled intercellular spaces without artiﬁcial inﬂuence, and it was proved experimentally that the gas-ﬁlled intercellular spaces, with a volume of 1000 m 3 and higher, form a complex network inside the tissue. However, 3-D imaging of gas-ﬁlled intercellular spaces revealed that these spaces were not completely interconnected and were disrupted in some parts. Moreover, the size distribution of gas-ﬁlled intercellular spaces demonstrated that the subdivision of intercellular spaces advanced with storage period. These observations and analyses suggested that the gas-ﬁlled intercellular spaces got blocked with water during senescence. This change in the network of gas-ﬁlled intercellular spaces with time after harvest will affect the gas diffusivity. © 2004 Elsevier B.V. All rights reserved. Keywords: Cucumis sativus L.; Intercellular air spaces; Postharvest; Three-dimensional reconstruction; X-ray CT 1. Introduction In plant tissue, free spaces called intercellular spaces are omnipresent. Intercellular spaces are mainly classiﬁed into two types depending on their  Supplementary data associated with this article can be found at doi: 10.1016/j.postharvbio.2004.04.002. ∗ Corresponding author. Tel.: +81-3-5841-5373; fax: +81-3-5841-8174. E-mail address: kuroki@bpe.en.a.u-tokyo.ac.jp (S. Kuroki). origin (Ichikawa, 1966). One is schizogenous inter- cellular spaces originating from the separation of cells along their edges. The other is lysigenous intercellular spaces originating from dying cells. These intercellu- lar spaces are also classiﬁed into two groups on the basis of their contents, namely gas or liquid. Little attention has been paid to intercellular spaces; how- ever, they play various indispensable roles in higher plants. Particularly, gas-ﬁlled intercellular spaces have many important functions, and one of which is a gas transport system inside plants (Raven, 1996). 0925-5214/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.postharvbio.2004.04.002