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![Studies of leaf water content in smart agriculture using THz technologies: a review](https://image.oaes.cc/120f7a4f-a9a4-4b88-8e1a-d941b4f44760/4926.fig.8.jpg)
Figure 8. Real part of permittivity of baby-leaf (A) and basil leaf (B) measured by Zahid et al. on four consecutive days[9]. Permittivity decreases while time progress, with the consequence that at these frequencies the leaves are transparent. A careful analysis shows how the leaves have a high permittivity on day 1, this is due to a greater quantity of water present in the fresh leaves. Otherwise, with the passing of the days and with the gradual loss of water in the leaves, there is a decrease in the permittivity values.