Reproductive Biology Characteristics Of Allium Caeruleum

This paper takes the distribution of the heterogeneous habitats Allium caeruleum as the research object.In the homogeneous habitat conditions, study on flowering phenology, pollen viability, stigma receptivity,mating system and pollination characteristics. To master the reproductive biology information, understand the special geographical environment in Xinjiang A. caeruleum reproductive adaptation strategy. For further study on different geographical distribution area and the genetic diversity of different ploidy A.caeruleum research provides evidence of reproduction biology and fitness, to lay the foundation for the development and protection of germplasm resources effective. The main results were as follows:(1)Different ploidy A. caeruleum flowering during June-August. Diploid and tetraploid in umbels spherical or spheroidal. Florets was intensive and without bulbils. Triploid florets was thinning, had bulbils,tepals were sky blue. The diploid and tetraploid were earlier than triploid 8-10 days. The bimodal curve model was adopted at flowering amplitude. The synchrony index was 0.8745( diploid) and 0.8208(tetraploid). It was exhibited a so-called “mass-flowering” pattern, was able to attract pollinators access and cope with the extreme weather.(2)Under 15-35 ?, the number of flowering and temperature between diploid and tetraploid were achieved extremely significant correlation( r=0.603, r=0.679, P<0.01). The diploid had the fastest flowering rate and it flower degree day was 2.334. Tepals expanding and anther dehiscencing were fast under high temperature. The flowering progress was influenced by temperature. The number of flowering and flowering duration between diploid and tetraploid were achieved significant correlation( r=0.785,r=0.991, P < 0.01), and the number of flowering and number of fruitlet were achieved extremely significant correlation(r=0.785, r=0.991, P<0.01). Temperature is a limit factor during the flowering phase in wild A. caeruleum germplasm. In order to ensure its reproductive success. The different ploidies form the special flowering phenology characteristics to improve the ecological adaptability.( 3) The floret experienced morphological changes of bullet, open mouth, spit anther, unfold,cohesion and wilting, which lasted 5-7 d. The anthers and the stigma existed spatial isolation in the process of floret opening and there were 12 dynamic changes that was from the first anther extending to all of six anthers shedding and from stigma elongation to wilting was needed 2-3 d; Under cloudy weather the anthers dehiscence were increased and the stigma wilting was delayed 0.5-1 d. The floral syndrome of A.caeruleum was protandry, dichogamy and herkogamy to prevent self-pollination.(4)Benzidine ?-naphthol staining, TTC staining, Carmine acetate dyeing, Pollen staining and Red ink staining were not applicable to the pollen vitality of A. caeruleum and its relative species. A. caeruleumand its relative species pollen viability was 85.37% after the anther dehiscence 2-4 h and pollen germination rate was 81.64%. The pollen viability and pollen germination rate were within 72 h. A.caeruleum and its relative species belonged to the short life pollen. The pollen viability and pollen germination rate were achieved significant correlation(r=0.914 to r=0.998, P<0.01). MTT method and the in vitro germination method can detect pollen activity of A. caeruleum and its relative species.In these A.caeruleum and its relative species, A. pallasii had the strongest pollen activity. The original habitat pollen vitality of A. caeruleum was obviously higher than that introduction conditions of pollen vitality.(5)The stigma receptivity was detected by both the MTT and the benzidine hydrogen peroxide methods. When filaments equaled to the style the stigma receptivity was to be detected partially, and when filaments over passed the style the stigma receptivity was to be detected totally. The partial overlap of the stamens and pistils could prevent the failure of cross hybridization. In A. caeruleum and its relative species,A. pallasii stigma had the earliest receptivity and lasts a long time.(6)The single flower of A. caeruleum had 16180-32130 pollens, the ratio of pollen to ovule(P/O)was 2697-5355 and the out-crossing index(OCI) was 5. The detection results of mating system showed that A. caeruleum has no spontaneous self-pollinating phenomenon and there was no wind pollination and apomixes. Triploid A. caeruleum only asexual reproduction, but diploid and tetraploid tends to be outcrossing and selfing fertility, they have outcrossing and mixed mating system features and needs floral visits. A. caeruleum also take the seed dormancy and asexual propagation compensation strategies to ensure the population reproduction successfully.( 7) Insects were pollinators of A. caeruleum, there were 5 orders 25 species. Diprera files and hymenoptera bees had the highest frequency of pollination. Insects pollination activity is mainly affected by temperature, insects pollination of optimum temperature between 24? to 29?. Different weather also has great influence on the pollination insects pollination frequency, In sunny day, insects pollination frequency is higher and stay a longer time on inflorescence.