Study on Pollination Compatibility of Superior Lonicera caerulea Individuals

In order to solve the problems including low fruit-bearing rate and low yield caused by blind plantation in production, the medium formula for pollen germination of Lonicera caerulea L. var. edulis Turcz. ex Herd., its pollination habit, self-compatibility and open pollination compatibility between different superior individuals were investigated with superior individuals from superior wild individuals of L. caerulea in Changbai Mountains as experimental materials. Self-compatibility and open pollination compatibility among different fine plants provide theoretical basis for its further application and further selection of new varieties. The results showed the optimal medium for germination of L. caerulea pollen was 27.5% sucrose ＋ 100 PPM boric acid with a pH value of 6.0. On this medium, the superior individuals L1, L2 and L3 had the pollen germination rates of 53.4%, 50.9% and 51.6%, respectively. The three superior individuals had no significant differences in the quantity of germinated pollen tubes, which ranged from 1 to 4. The three excellent single plants were the most likely to germinate a single pollen tube, accounting for 83.3% of the pollen germinated and 89.6% of the pollen germinated. Therefore, in production, it is necessary to plant L1 with a certain amount of pollination trees or plant it together with multiple species, to improve its yield. On the contrary, L2 and L3 have no need for pollination trees theoretically, but whether the fruits obtained by self-pollination and outcrossing differ in quality still needs further study.

Shortened anther-stigma distance reduces compatible pollination in two distylous Primula species

Aims Distyly has been regarded as an adaptation to improve compatible pollination between two floral morphs with reciprocal herkogamy.The hypothesis that the different positions of anthers and stigmas within flowers as well as their reciprocal position between morphs,reduce the probability of self pollination raised by Darwin has been rarely tested.in this study,we measured stigmatic pollen loads in response to reduced reciprocal herkogamy in two Primula species.Methods To see whether reciprocal herkogamy can increase compatible and/or reduce incompatible pollen deposition,thus promoting compat-ible pollination,we shortened the distance between anthers and stigmas within the flowers by changing the position of the corolla tube,to which the anthers were fused,i.e.reduced herkogamy in natural populations of Primula secundiflora and P.poissonii and quantified stigmatic pollen loads in the field over 2 years.Important Findingsin both species,stigmatic pollen loads were significantly higher in the long-styled(l-morph)than in the short-styled morph(s-morph)in both control and manipulated flowers,but percentage of compatible pollen in s-morph were higher.Flowers manipulated to halve the anther-stigma distance showed a similar pattern for 2 years:total pollen grain counts on stigmas did not differ significantly but compatible pollen grains in l-and s-morphs were significantly decreased in both species.The percentage of compatible pollen loads was decreased by 68.7%in P.secundiflora and 65.3%in P.poissonii in l-morphs,while it decreased by 30.6%and 2.9%in s-morphs,respectively.our manipulation of the relative position of anthers and stigmas in the two distylous species indicated that a lower degree of herkogamy reduced compatible but incompatible pollen transfer was likely to increase.The higher proportion of compatible pollen in the s-morph than in the l-morph in the two Primula species could be attributed to the accessibility of two-level sexual organs,floral orientations and pollinator behaviors.This is a first attempt to manipulate intraflower herkogamy for understanding adaptation of heterostyly,shedding insights into how the reciprocal herkogamy promotes compatible pollination.