Study On Reproductive Biology Of Lilium Davidii Var.unicolor Salish

Lilium davidii var.unicolor Salish(2n=2x=24),which belongs to the genus Lilium L.in Liliaceae family,is a variety of Lilium davidii Duchartre.It is a perennial bulbous herb with strong adaptability and has garden ornamental,edible and medicinal value.This study uses the L.davidii var.unicolor Salish as a test material,and its flowering phenology,flower morphological characteristics,meiosis of megaspores and microspores,formation of female gametes and male gametophytes,reproductive system,pollen vigor and stigma receptivity,and flower-seeking insects were systematically observed.Fluorescence microscopy and paraffin sectioning techniques were used to study the growth of pollen tube and embryonic development process,revealing the reproductive biology characteristics of L.davidii var.unicolor Salish.The main results were as follows:The flowering period of L.davidii var.unicolor Salish population lasted for 8 days,the single flowering period lasted for 5 days,the vegetative growth period lasted for 69 days,the reproductive growth period lasted for 77 days,annual growth cycle lasted 106 days,the L.davidii var.unicolor Salish sprouting period is April 20 th,and the aboveground part began to dry up on August 4th,ending year growth cycle.The flowering of L.davidii var.unicolor Salish began at 2 am in Shenyang area,and the outer flower was lifted upwards.At 4 o'clock,the flower was curled up to the horizontal height.At 9 am on the flowering day,the inner and outer flower quilts were rolled up to the maximum,and the anthers were polluted bright red.The morphological characteristics of the flower parts indicate that the male and female genus of L.davidii var.unicolor Salish are ectopic,and the characteristic and morphological indexes of the flower part are basically increased first and then decreased.The L.davidii var.unicolor Salish breeding system is evaluated by two indexes,the outcrossing index(OCI)and the pollen-ovule ratio(P/O).Results were as follows: the outcrossing index is 5,according to the Danfi classification criteria,the breeding system is outcrossed,partially self-compatible,and requires a pollinator.The pollen-ovule ratio P/O value is 6896.29±456.68,which is between 2108.0 and 195525.0.According to the Curden classification criteria,the breeding system is an obligate heterozygous breeding system.The experiment was carried out to observe the insects of L.davidii var.unicolor Salish.The insect species mainly include the species Eristalis arvorum,the species Eristalis tenax,the species Apis cerana Fabricius,etc.Through field observations,the visitor only crawled back and forth between the anther and the perianth,failing to pass the pollen to the stigma.Fluorescence observation revealed the presence of wind pollination,but due to the lack ofvitality of pollen,the effective pollen is not accepted on the head of L.davidii var.unicolor Salish.Under natural conditions,neither of the two pollinators have pollinated L.davidii var.unicolor Salish.The meiosis of the microspore of L.davidii var.unicolor Salish is a normal continuous splitting pattern.The anther is composed of 4 pollen sacs,the middle part is the vascular bundle,the mature pollen is oval,and the mature anther is filled with pollen grains.The meiosis of the megaspores of L.davidii var.unicolor Salish resulted in the formation of four megaspore nucleus,and the four megaspore nucleus undergo three mitosis to form one egg cell,one central cell(with two polar nuclei),three antipodal cells and two helper cells.The embryo sac development type belongs to the fritillary type embryo sac,the mature pistil ovary lower position,the middle axis placenta,and the ovary is formed by 3 carpels,and the ovule is inverted.In terms of pollen vigor and stigma receptivity,the pollen vigor of L.davidii var.unicolor Salish can only last for about 12 h,and it is the most active at 8 o'clock in the morning of flowering,about 80%.With the flowering process,pollen activity begins to decline.Pollination of L.davidii var.unicolor Salish,time should be carried out during the high period of pollen vitality.The head of L.davidii var.unicolor Salish is receptive before flowering,and the cultivating ability is maintained for about 6 days.Among them,the stigma is the most receptive in the 0d and 1d flowering.Fluorescence microscopy was used to observe the pollen germination and pollen tube growth of L.davidii var.unicolor Salish grown under natural conditions and L.davidii var.unicolor Salish after conventional self-pollination.The results showed that the presence of pollen grains was observed on the stigma of L.davidii var.unicolor Salish grown under natural conditions,but the pollen activity was extremely low,showing the failure to emit pollen tubes or the pollen tube that failed to grow through the stigma;Most of the L.davidii var.unicolor Salish after self-pollination showed normal growth,and a few abnormal phenomena such as pollen tube fold growth and enamel accumulation.Embryology observation of ovary or expanded capsules of ovary and L.davidii var.unicolor Salish pollinated for 5d,10 d,15d,20 d and 25 d by paraffin sectioning at 10 d,15d and 20 d.The results showed that after 5 days of natural flowering,the overall shape of the ovary is reduced.After 10 days,the blastocyst began to disintegrate.After 20 days,all the cells in the ovary were connected into one piece,which is about to wither and fall;After 96 hours of pollination of L.davidii var.unicolor Salish,the pollen tube can reach the ovule,and then the pollen tube enters the embryo sac to complete the fertilization.After 5 days of pollination,the formation of fertilized nucleus can be observed and the double fertilizationcan be completed.After 10 days of pollination,two mitotic ends were completed and a four-cell proembryo structure is formed.After 15 days of pollination,the four-cell protoplasts divide to form pear-shaped embryos,which then develop into torpedo-shaped embryos,shield-shaped embryos,and mature embryos.The results of artificially controlled pollination test showed that the L.davidii var.unicolor Salish was partially self-compatible,outcrossed,intimate,inferior.Influencing factors of self-incompatibility include pollen vigor,pollination time,stigma surface inhibitor and pollen tubes grow down the style.