| In this paper the pollen morphology of55cultivars of pomegranate (Punica granatum L.)from eight eco-geographical populations in China and biological characteristics of pollengermination have been studied systematically. The pollen morphology was examined by SEM(scanning electron microscope). Through the study on pollen’s shape, size, exineornamentation,germinator and so on, the purposes of the study are to establish a set ofquantitive criteria of pollen morphology for pomegranate and check for the relationshipbetween pollen morphology and variety evolvement, classification; and on the other hand toobserve the course of pollen germination, to find the optimal culture conditions of pollengermination and to study the effects of plant growth regulators on pollen germination andpollen tube growth, which are the important data for pomegranate breeding and germ plasmresource research. The results of the experiment are as follows:1. Pollen morphological characters of55pomegranate cultivars. Pollen grains ofpomegranate were prolate (P/E=1.29-1.96) or perprolate (P/E>2) spheroid in equatorial viewand three-lobed monads, generally rounded or triangle in polar view. The mean length ofpolar axis (P) varied from22.75μm to31.5μm and the equatorial axis (E) from12.75μm to17.75μm. The pollen was mediansize, according to Erdtman’s NPC classification system, it’sthe type of N3P4C5. Aperture hole membrane form was evagination or no evagination. Threetypes of exine ornamentation were psilate with verrucae, micromesh verrucae and scabrateverrucae.2. Results of principal component analysis show that the important pollen morphologicindexes in classifying pomegranate cultivars are: colpus length, polar axis length, P/E, equatoraxis length, exine ornamentation, aperture hole membrane form, polar view and colpus width.The general important characteristics are pollen size, characteristic of exine ornamentationand characteristic of aperture hole membrane.3. Our cluster analysis results indicated that the classition of pollen morphology ofpomegranate in China was basically discordant with the morphological classification. Itshowed that pollen morphological features were not related with pomegranate morphologicalcharacteristics such as the color of fruit or flower, the flavour of fruit.4. To find the optimal culture conditions of pollen germination of pomegranate cultivar‘Taishanhong’, we design orthogonal experiment L9（33）of pollen germination. The results showed that the optimal culture conditions of pollen germination involved10%sucrose，0.005%H3BO3and pH was set as7.0.5. To observe the course pollen germination of pomegranate cultivar ‘Taishanhong’, wefound that the time of pollen germination was3h.6. We studied the effects of plant growth regulators on pollen germination and pollen tubegrowth. The result showed low concentration6-BA (1~10mg/L) and2,4-D (1~5mg/L)promoted the pollen germination and tube growth. When they were in higher concentrations,inhibition effects were observed. The optimal concentration for pollen germination pollen andtube growth was10mg/L (6-BA) and5mg/L (2,4-D). However, NAA (1~30mg/L) and PP333(50~800mg/L) had some inhibitory effects on pollen germination and tube growth inpomegranate. The inhibitory effects strengthened with concentration increasing. |
