Search

Ardisia humilis is an excellent wild ornamental plant. For the purpose of fully utilization of this elite germplasm, the flowering biology and breeding system of this plant had been explored in this study. We conducted field investigation in the flowering phenology, flower-visiting insect and their visiting behaviors on A. humilis individuals introduced in homogeneous garden. Furthermore, pollen viability and stigma receptivity were detected by pollen germination in vitro and benzidine-hydrogen peroxide method, respectively. Combined with artificial pollination,the self-compatibility and the self-pollination of A. humilis were also analyzed in this study. The results were as follows: (1) The florescence of A. humilis was from mid-late May to early June, and the full flowering period was at the end of May. The flowering period of the population, single plant and single flower were approximately 25 d, 17-20 d and 1 d, respectively. (2) A. humilis developed protogynic bisexual flowers, the pistil ripened first with partial overlaps on mature stage of pistil and that of stamen, while stigma remained receptivity until 1 d after stamens fall. (3) With the out-crossing index (OCI) value of 4 and pollen / ovule value of 5.61×103, the breeding system of A. humilis was considered to be outcrossing with partial self-compatibility, and the pollinator insects were essential. (4) The seed set of natural pollination ranked the highest level (average 52.96%), followed by that of autogamy (52.29%) and of artificial-cross pollination (50.33%), with no significant differences among the three (P>0.05), but significantly higher than that of artificial geitonogamy (28.67%) (P<0.05). This study indicated that, beside of being excellent flowering plant, A. humilis was also a potentially important ornamental fruit plant due to the generalized pollination system and the strongly autogamy ability which enhancing the high success of fruits development from blossoms. (5) Lasioglossum sp. 1, Lasioglossum sp. 2 and Halictus sp. were the most observed floral visitors on Ardisia humilis. This study provides an important theoretical reference for the resource utilization and germplasm innovation of A. humilis. [ABSTRACT FROM AUTHOR]

Primula Hance(Gesneriaceae)is a group that has attracted much attention in recent years. Its intricate species diversity and its endemic distribution among species have aroused great interest among taxonomists and botany researchers. Except for a few species, like Primulina eburnea (Hance)Y. Z. Wang, most species have a very narrow distribution range, which belong to narrow distribution species or endemic species. In order to reveal the effects of the pollination biology and breeding system of P. eburnea on its reproductive process and colonization ability, we systematically studied the flowering phenology, the pollen and stigma viability, the species and visiting behavior of flower visiting insects, the pollen ovule ratio, the OCI index and the seed setting rate of manipulated pollination of P. eburnea. Besides, we explored whether its reproductive processes such as pollination had a positive effect on the spread of P. eburnea. The results showed that the natural flowering stage of P. eburnea was from March to May, and the entire flowering stage was about 45 d. Its full flowering stage was about 20 d, and the single flower flowering stage was 6-8 d. Pollens had the strongest viability 1-2 d after flowering, stigma did not have receptivity before flowering. The pollen ovule ratio was 537, and the hybridization index was 5. Bagged and emasculation could not bear fruit, indicating that this species did not have apomixis. Compared with natural pollination, the seed setting rate of hand self-pollination was slightly lower, and the seed setting rate of hand xenogamy was slightly higher, indicating self-compatibility. The main pollinators of P. eburnea were Anthophora florea and Bombus sp. Therefore, higher nectar volume, larger pollen amount and stronger pollen viability of P. eburnea were obviously beneficial for it to complete the entire process of pollination and reproduction. This result was obviously conducive to the colonization of P. eburnea and then widely spread in the karst areas of South China to Southwest China. [ABSTRACT FROM AUTHOR]

Hopea chinensis is one of the representative tree species of tropical seasonal rainforests in China. It is an endangered and protected plant with beautiful tree shape and cold tolerance. To clarify its pollination biology, and breeding system and demonstrate its reproductive potential in Guilin, where this species was introduced for protection, we conducted the following experiments: the observation of flowering phenology, the measurement of floral size and scent, the estimation of the breeding system by out-crossing index(OCI), the pollen-ovule ratio(P/O), pollen viability and the stigma receptivity and self-pollination, the observation of pollinators and the test of their pollination effectiveness, the assessment of reproductive potential and pollination limitation by hand cross-pollination. The results were as follows:(1)The flowering season of H. chinensis in Guilin Botanical Garden is from the end of July to the end of September. It lasts about 60 d. An inflorescence flowers for about 12 d, and the anthesis of a single flower lasts about 3 d. The flowers begin opening from 17:00 to 18:45.(2)H. chinensis is not dichogamous but herkogamous with stigmas higher than anthers. The period of high pollen vigor and that of high stigma receptivity largely coincide.(3)The outcrossing index(OCI)was four and pollen/ovule ratio(P/O)was 10 788±984.(4)Neither flowers self-pollinated nor thoses bagged all the tome set any fruitse, fruit set did not differ significantly between natural pollination and hand cross-pollination.(5)Fungus gnats were the only flower visitor to the H. chinensis in Guilin Botanical Garden and flowers set no fruits with fungus gnat excluded.(6)The floral scent is dominated by β-elemene,(E)-7,11-dimethyl-3-methylene-1,6,10-dodecatriene and 1-caryophyllene. In conclusion, H. chinensis breeding system is self-incompatible, and it relies on fungus gnats for fruit production. It can set fruits and produce mature seeds in Guilin. The results can promote the protection and propagation of H. chinensis. [ABSTRACT FROM AUTHOR]

Jatropha curcas is likely to become one of the key energy crops in the world because of high oil content in seed which can be refined into high quality biodiesel. J. curcas widely distributes and cultivates in many tropics and sub-tropics areas of China. Due to inadequate pollination and very low productivity, J. curcas was a wild or semi-wild tree for a long time. Effective pollination is a prerequisite for fruit-set and seed-set of J. curcas. Information on the most suitable ingredient concentration ratio of B-K medium which was widely used to pollen culture in vitro for pollen germination and inactions among ingredients in vitro is required to increase rate of hybrid seed set and seed production. Gathered mature pollen grains when petals opened and the anther just began scattering pollen in primary flowering time to do pollen germination test. Ingredient concentration ratio was optimized by response surface methodology(RSM)based on the Box-Behnken design(BBD). The primary variables chosen were sucrose, H3BO3, Ca(NO3)2 · 4H2O and KNO3. A total number of 30 runs were tested. We constructed a response surface model between the pollen germination rates and four ingredients for the culture medium in vitro by R 3.0 software. The effect order of 4 factors to influence germination rate were: sucrose > H3BO3 >Ca(NO3)2 · 4H2O>KNO3. There were significant interactions of pollen germination between sucrose and H3BO3, sucrose and Ca(NO3)2 · 4H2O, sucrose and KNO3. The optimal ingredient concentration ratio which supported the germination of pollen and growth of pollen tubes was 13.77% sucrose + 32.14 mg · L-1 H3BO3+ 22.21 mg · L-1 Ca(NO3)2 · 4H2O + 19.95 mg · L-1 KNO3 + 200 mg · L-1 Mg(SO4)2 · 4H2O. Under this condition, the germination rate theoretically achieved 99.73%. The verification test were made corresponding to the optimal ingredient concentration ratio, the results of pollen germination experiments showed that pollen germination rates of 98.97%, the proportion matched theoretical response value well. It can also verify the effectiveness of the BBD-based response surface model and analysis technique in obtaining optimal ingredient concentration ratio for pollen germination. [ABSTRACT FROM AUTHOR]