| Torreya grandis(T.grandis Fort.Ex Lindl.cv.'Merrillii)is the only artificially cultivated Chinese unique rare and nut in the Torreya genus of Taxus family,and Zhejiang,Anhui,Jiangxi,Hubei and other places are the main planting areas.Since the first introduction in Guizhou Botanical Garden in 2012,after nearly 10 years of cultivation research,combined with the producing management experience,it has been found that the yield of T.grandis is largely affected by the quantity and quality and pollination methods of pollen.In this paper,T.grandis introduced and cultivated in Guizhou Province was taken as the research object.T.grandis pollen of different periods were collected for experimental analysis,and the time of collection,pollen viability,storage temperature and pollination method were experiment.The results were as follows:1.TTC staining method and in vitro pollen culture method were used to study the pollen viability of T.grandis.(1)TTC determination method: under the condition of the same 0.5% TTC dye concentration,different p H values and different culture temperatures led to different pollen staining rates.At p H 6.0,the lowest pollen viability rate was 17% at 25?,and at p H 7.0,the highest pollen viability rate was 52% at 30?.With the increase of TTC dye solution p H,the pollen viability decreased,and at p H 7.5,the pollen viability rate decreased to 46% at 30?.In general,the p H value of the solution was 7.0,and the highest pollen activity(52%)was measured at 30?.(2)In vitro culture method: sucrose and boric acid could promote pollen germination of T.grandis at a temperature of 28? and a certain concentration range.When the two concentrations were 100 g/L and 100 mg/L,respectively,pollen germination rates reached the highest 46.89% and 48.31%,respectively.Through further orthogonal test,the optimal culture conditions were as follows: 100 g/L sucrose +50 mg/L boric acid + 28?,the germination rate could reach 49.97%.2.Pollen was collected in different periods of T.grandis when the male flowers blooming,and the pollen vigor was different at different time of collection.The pollen viability was significantly affected by the time of collection,and the pollen viability was gradually decreased with the extension of flowering period.In general,the best time for pollen collection is the initial flowering stage(the latest to before the full flowering stage).The male flower type(small flower type I and large flower type II)had no significant effect on pollen viability.3.The pollen viability of T.grandis was significantly affected by different pollen storage temperatures after collection.The pollen viability decreased significantly when stored at different temperatures for 14 days.The limits for high pollen viability without affecting pollination effect are as follows: 0-7 d for storage at room temperature;Storage at 4?for 0-14 days;It can be stored for 0-30 days at-18?.Considering various factors,4? can be used as the best temperature for pollen storage,but the best temperature should not exceed 14 days.4.Effects of different pollination methods on the pollination rate,fruit setting rate and fruit quality of T.grandis.Different pollination methods of the same pollen type had significant effects on the pollination rate.The highest pollination rate was 96.48% under the point method,followed by91.33% under the spray method,and the lowest was 85.73% under the natural method.However,under the same pollination method,different pollen types had no obvious effect on the pollination rate.Different pollination methods had significant effects on the fruit-setting rate.The fruit-setting rate was 51.6% in the treatment of florets ? and less than 50% in the treatment of other methods.Fruit setting rate was 48.36% under spraying treatment,and37.25% under natural pollination treatment was the lowest.Although the pollination rate and fruit-setting rate of point feeding treatment were high,spraying method was suitable for large-scale planting in view of pollination efficiency.Different pollination methods had no obvious effects on fruit quality indexes such as fruit vertical and horizontal diameter,seed shape index,fresh fruit single weight,seed coat thickness and seed quality.Combine the above technologies,the pollen of T.grandis introduced and cultivated in Guizhou is suitable to be collected from the initial flowering stage to the full flowering stage and stored dry at 4?(no more than 14 days).After spraying pollination,the pollination rate of T.grandis can reach more than 90% and the final fruit set rate after fruit drop in the next year more than 48%,both of which are significantly higher than natural pollination.In the production practice of T.grandis in Wuchuan and other bases,the average fruit-setting rate of adult trees was significantly higher than that of natural pollination,and the yield per unit area was increased to 10-12 kg/ plant,and the effect was obvious. |
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