Study On Reproductive Ecological Characteristics Of Three Pioneer Shrubs On Slope In Yantai,China

Ziziphus jujuba var.spinosa(Bunge)Hu ex H.F.Chow is a deciduous shrub of Rhamnaceae.Vitex negundo var.heterophylla(Franch.)Rehd is a deciduous shrub of Lamiaceae.Grewia biloba var.parviflora(Bunge)Hand.-Mazz.is a deciduous shrub of Tiliaceae.The three species are common slope pioneer shrubs in Yantai.This article takes Z.jujuba var.spinosa,V.negundo var.heterophylla,and G.biloba var.parviflora as research objects.In order to understand the sexual reproduction mechanism of common local wild shrub species,this article focused on flowering ecology,pollination ecology,breeding system,plant biomass reproduction and distribution,and seed physiology.Research and understand the sexual reproduction mechanism of local wild shrubs,with a view to providing theoretical guidance and technical support for protection of excellent wild shrub resources and its applyment in slope greening protection projects.The main results are as follows:The initial flowering period of Z.jujuba var.spinosa is at the end of May,and the final flowering period is around the beginning of July.The flowering period of the Z.jujuba var.spinosa is about 40 days.The flowers are yellow-green and bisexual,flower diameter is 4.94 mm ± 0.20 mm,the anther is 5,the maximum of pollen viability of Z.jujuba var.spinosa is 62.04%±15.09%,in the same period,the stigma receptivity is also strongest.The highest pollen germination rate of Z.jujuba var.spinosa is 42% at25?,and 25? is the optimum germination temperature of Z.jujuba var.spinosa,which is roughly in line with the flowering temperature of Z.jujuba var.spinosa.The first flowering dates of V.negundo var.heterophylla are in the early July,whose population flowering period was 55?60 days.The corolla is light purple.The flowers are bisexual.The flower diameter is 7.44mm±0.32 mm.The stamens are longer than the corolla,and the stigma receptivity of V.negundo var.heterophylla is strongest in the initial flowering period but it's still exist in the wilting stage and the bud stage.and the pollen viability of the V.negundo var.heterophylla can reach 56.37%±13.90%in the wilting stage.The germination rate is not significant different at 25? and 30?,and it is less than 10% at 20?.There are bisexual flowers and unisexual flowers in the G.biloba var.parviflora,and the initial flowering period is at the end of June.The stigma is enlarged,discshaped,lobed.The flowering period of the population lasts for 50-55 days,the female plant has a single flower period of 4 days,the male flower has a single flower period of 3 days,and the bisexual plant has a single flower period of 3 to 4 days.Flower diameter: male flower> bisexual flower > female flower.Stigma diameter:female flower> bisexual flower> male flower.The stigma of the male flower is degenerated and have no receptivity.The pollen vitality of the male flower is higher than that of bisexual flower.The germination rate can reach 20% at 30 ?.Through comparing the species diversity of flower-visiting insects on the three slope greening shrubs of Z.jujuba var.spinosa,V.negundo var.heterophylla and G.biloba.var.parviflora,we found that Shannon-Wiener index(H'): Z.jujuba var.spinosa>The bisexual flower of G.biloba var.parviflora> The male flower of G.biloba var.parviflora > V.negundo var.heterophylla> The female flower of G.biloba var.parviflora.Margalef abundance index(Dm): Z.jujuba var.spinosa> V.negundo var.heterophylla> The male flowers of G.biloba var.parviflora> The bisexual flowers of G.biloba var.parviflora > The female flowers of G.biloba var.parviflora.Pielou index(Jsw): The bisexual flowers of G.biloba var.parviflora > The female flowers of G.biloba var.parviflora > The male flowers of G.biloba var.parviflora > V.negundo var.Heterophylla > Z.jujuba var.spinosa.The species abundance of flower-visiting insects of Z.jujuba var.spinosa is higher,but the evenness indices is lower.The abundance of flower-visiting insects on the G.biloba var.parviflora is the lowest but the evenness indices is not the lowest.According to the estimation of out-crossing index and pollen ovule ratio,the outcrossing index of Z.jujuba var.spinosa,V.negundo var.heterophylla and G.biloba var.parviflora are 4 ? 3or 4 ? 4 respectively,and the pollen ovule ratio is3850?4150,9145?22605,59596.75?101653.25.According to these three plant breeding systems,all are mainly outcrossing,and some are self-compatible.Comprehensive bagging experiment results confirm that these three plants all have selfing,but the fruit setting rate of selfing is quite low.In the natural state,the fruit-setting rate of Z.jujuba var.spinosa and V.negundo var.heterophylla are both more than 30%,the highest fruit-setting rate of the female flower of the G.biloba var.parviflora can reach more than 50%,and the female flower is about 28%.The biomass distribution of Z.jujuba var.spinosa roots,stems,leaves and flowers were 16.51g±0.16 g,19.17g±0.26 g,15.70g±0.2g,0.58g±0.11 g.Those of V.negundo var.heterophylla were 4.90g±0.1g,9.21g±0.13 g,6.97g±0.02 g,3.67g±0.08 g.Those of the hermaphrodite strains of G.biloba var.parviflora were 18.78g±0.35 g,25.87g±0.57 g,13.39g±1.31 g,6.25g±0.37 g.It can be seen that there are differences in the biomass distribution of different components of different plants.The inflorescence biomass and plant biomass of Z.jujuba var.spinosa,V.negundo var.heterophylla and G.biloba var.parviflora are significantly positively correlated with plant biomass.The reproduction input of Z.jujuba var.spinosa,V.negundo var.heterophylla and G.biloba var.parviflora are positively correlated with plant size.The thousand-grain weight of Z.jujuba var.spinosa is 232.41g±19.76 g,it of G.biloba var.parviflora is 40.09g±1.89 g and it of V.negundo var.heterophylla is7.60g±1.62 g.The seed shell of Z.jujuba var.spinosa is lignified.The seeds of Z.jujuba var.spinosa have black hard shells.The shell of the seed is hard and covered with oil film.The seeds of Z.jujuba var.spinosa have the fastest water absorption rate.Soaking in warm water can increase the germination rate of Z.jujuba var.spinosa and V.negundo var.heterophylla.The seed germination rate and germination time could be greatly improved by soaking seeds damaged by gibberellin and stratification treatment.The gibberellin and stratification treatment could break seed dormancy and accelerate seed germination.