AbstractThe development of fruits of black currant cv. Ben Alder from flower to maturity was studied non-invasively by NMR microscopy, using attached and detached fruits. The images were compared with those from low temperature scanning electron microscopy (LTSEM) and conventional resin histology. The NMR images derived from 2-D and 3-D datasets showed a previously unreported growth of arillar tissues to the extent that they almost completely occluded the locular cavity. LTSEM and resin histology revealed that no fusion occurred between the arillar tissues and the gelatinous sheath surrounding each seed, or between the arillar tissues and the endocarp. Discontinuities between these tissues caused magnetic inhomogeneities which resulted in these structures being clearly resolved by gradient echo imaging sequences. During seed maturation the endosperm changed from high (bright) to low (dark) signal intensity as lipid reserves formed and solidified. The gelatinous sheath had high signal intensity throughout maturation. High lipid concentration in seeds was manifested by chemical shift effects in the images. The increasing viscosity of the endosperm was reflected by a decrease in spin-lattice relaxation times. The funiculi, throughout development of seeds, appeared in NMR images with low signal intensity. 3-D surface-rendered reconstructions illustrated the complexity of the spatial array of seeds and funiculi arising from parietal placentas within the loculus. All other vascular tissues in the pericarp and placentas were resolved as a small bright core surrounded by a dark region, within a matrix of moderate signal intensity. Conventional studies showed that the bright core discernible by NMR imaging encompassed an entire vascular bundle whereas the darker surrounding region represented small parenchyma cells with pronounced intercellular gas spaces. Other regions of the pericarp which included extremely large parenchyma cells had few intercellular spaces and consequently gave rise to brighter regions in the image.