Abstract:
The usefulness of guard cell length and stomatai frequency as indirect ploidy indicators was evaluated for seed-grown plants of Oryza punctata Kotschy ex Steud. Leaves were collected from 3-week old plants and were again collected from the same plants that have been allowed to grow for another four weeks. Measurements showed that the mean guard cell length for 3-week old diploid plants was 14.01 ±1.46 and 16.02 ±1.69 for tetrapioids and these differed significantly (a=0.01) from each other. Significant differences (a=0.01) were also observed between the mean guard cell lengths of mature diploid and tetrapioid plants. Measurements of stomatai frequency were taken from leaves collected from mature plants. The frequency of stomata was shown to decrease significantly (a=0.01) as the ploidy level increased, with a mean of 37.04 ±4.04 for diploids and 26.09 ±3.71 for tetrapioids. It was concluded that guard cell length and stomatai frequency are useful in detecting ploidy variation in Oryza punctata. However, the high degree of overlap between the ranges limits the accuracy of both guard cell length and stomatai frequency as a method of separating diploid and tetrapioid plants.
