Evaluation of pollen viability, stigma receptivity and fertilization success in Lagerstroemia indica L.

Abstract

To provide theoretical basis for artificial pollination in Lagerstroemia indica L., pollen viability and stigma receptivity were tested and the morphological change of stigma was observed. Pollen viability tested by in vitro culture, stigma receptivity examined by benzidine-H 2 O 2 testing and fruit set estimated by field artificial pollination were analyzed in this study. The maximum pollen viability was observed at 10:00 am one day of anthesis (DA), of which 'Hong Wei' (46.2%) was significantly lower than that of 'Yin Wei' (56.8%) and 'Zi Wei' (62.5%). The stigma receptivity of the three crape myrtle cultivars was sustained for eight days, which was 95.7 to 96.9% at 1 DA to two days after anthesis (DAA), then declined to 75.5 to 79.9% at 3 to 4 DAA and 50.6 to 59.7% at 5 to 6 DAA, and only 29.5% at 7 DAA. Higher stigma receptivity was associated with columnar style, upward stigma, green and wet papillae and copious exudates at stage 1 (1 DA to 2 DAA). Frequencies of fruit set at stage 1 (74.4%) and stage 2 (3 to 4 DAA) (78.9%) were significantly higher than that at stage 3 (5 to 6 DAA) (21.9%). So, selecting pollen at 10:00 am 1 DA and stigma of 1 DA to 4 DAA was a strategy to enhance fruit set in the future artificial hybridizations for crape myrtle.

Significance of stigma receptivity in intergeneric cross-pollination of Salix × Populus

“…Similar methods of SR evaluation have been reported in other plant species [35,36]. Short SR time appears to be characteristic of Salix species, together with the pattern of stigma structure, both expressing a high degree of similarity in four willow genotypes.…”

“…A second, simpler and less expensive procedure, showing stigma receptivity through the presence of hydrogen peroxide (H 2 O 2 ), was the Perex Test (Merck Chemical 16206), in which the appearance of air bubbles and the pale-yellow color of the solution droplet indicated a presence of peroxidases [33] and esterases [34,35].…”

“…Other methods of determining receptivity focus on indication of the activity of enzymes such as esterases, peroxidases, and acid phosphatases, on the stigma surface [32][33][34][35]. Stigma receptivity should be particularly analyzed in order to: (i) find out precisely the anthesis stage of inflorescence/ flower/pistil for hand cross-pollination; (ii) indicate the pre-or post-receptive stage of stigmas for improved pollination efficiency; (iii) study the pollen/stigma incompatibility; (iv) propose a new/special breeding system [34,35].…”

Floral biology and reproductive potential of Annona hybrid Arka Sahan

“…For assessing stigma receptivity, hydrogen peroxidase activity (6%) was utilized as a determinant (Chen et al, 2013). Fruit set evaluation involved manual pollination of flowers daily, employing Balanagar pollen as the pollen source, conducted between 6:30 to 7:30 AM.…”