2.6. Stomatal Characteristics

The effect of different ploidy levels on regenerants was also investigated by morphological analysis of mesophyll epidermal structures under light microscopy. Mature leaves were used to analyze six quantitative parameters regarding morphological characteristics of diploid and tetraploid regenerants as reported in Table 2. A few strips of epidermis were torn from the abaxial side of fully expanded leaves from diploid and tetraploid plants. Tissue segments were mounted on a microscope slide with a drop of distilled water and a coverslip to measure stomata size. The sizes of 20 stomata for each sample were evaluated under a light microscope (Optech Biostar BM 45 trinocular microscope with a Tucsen ISH 300 digital camera). Immediately after the preparation, the number of chloroplasts in the two guard cells of the same stomata was counted directly from microscope slide. Data were collected using ISCAPTURE Version 3.0. The stomatal index (SI) was also measured as (S/(E + S)) × 100, where S is the number of stomata and E is the number of epidermal cells per unit leaf area [59].

Morphological comparison of diploid and tetraploid leaves.

Stomatal index (SI) values are also reported. Data represent mean ± standard deviation (n = 10). Different lowercase letters within rows indicate a significant difference at the 5% level (p < 0.05).