链霉素和赤霉素诱导欧亚种葡萄‘玫瑰香’无核结实的效果及机制研究

Efficiency and mechanism of seedless berrying induced by streptomycin and gibberellins in grape(Vitis vinifera)

【目的】探讨链霉素(SM)及赤霉素(GAs)诱导欧亚种葡萄有核品种无核结实的可行性及其诱导无核结实的机制。【方法】以8 a(年)生欧亚种葡萄有核品种‘玫瑰香’为实验材料,在满花前11 d至满花后4 d的2周期间用SM 200mg·L^-1、GAs40 mg·L^-1水溶液分别浸蘸花穗,探讨适宜使用时期。在满花当日用不同浓度SM、GAs及SM和GAs的混合液浸蘸花穗,探讨适宜使用浓度,并和GA3处理作了比较。所有处理花后2周再次用25 mg·L^-1的GAs溶液浸蘸果穗促进果粒膨大。【结果】从满花前7 d到满花后4 d期间用SM 200 mg·L^-1浸蘸花穗,各处理无核率都达100%。满花当日使用SM 50 mg·L^-1和100 mg·L^-1处理的无核率接近100%,SM 200 mg·L^-1+GAs25 mg·L^-1和SM 200 mg·L^-1+GAs40mg·L^-1无核率也达100%。但同期的GAs和GA3处理无核率较低。切片观察发现,SM各处理虽然使柱头花粉粒萌发及花粉管在雌蕊各部位的伸长都受到抑制,但到达珠孔的花粉管数目仍有0.8~1.4个(对照3.8个)。而满花当日的正常胚珠率、胚囊率却低于16.6%(对照为94.17%)。【结论】满花前1周至满花后4 d期间,SM 200 mg·L^-1单用或添加GAs25 mg·L^-1的水溶液浸蘸葡萄的花穗可以有效诱导欧亚种葡萄的无核结实。SM处理后雌蕊的胚珠和胚囊发育异常,是其诱导无核结实的主要原因。赤霉素对欧亚种葡萄的无核效果较差,有待进一步研究。

【Objective】Comprehensive study was designed to understand the mechanism and the feasibility of applying streptomycin(SM)and gibberellin(GAs)to induce seedless grape berries(Vitis vinifera).【Methods】The SM and GAs were applied on 8-year-old of‘Muscat Hamburg’grapevines at a different period with various concentrations.Starting from 11 days before flowering until 4 days after flowering,‘Muscat Hamburg’inflorescences were dipped in SM(200 mg·L^-1)and GAs(40 mg·L^-1)solutions.Furthermore,to promote berry size,they were treated with GAs(25 mg·L^-1)after two weeks of flowering.Besides,to evaluate the best application treatment,the inflorescences were treated with GA3(25 and 50 mg·L^-1),GAs(25,40 and 50 mg·L^-1),SM(50,100 and 200 mg·L^-1),SM 200 mg·L^-1+GAs 25 mg·L^-1,and SM 200 mg·L^-1+GAs 50 mg·L^-1 at full bloom stage.Afterward,within 2-weeks of flowering,they were treated with GAs(25 mg·L^-1).For all treatments,the number of spikes in the ear was investigated during the hard-core period and the berry set rate was calculated.The following parameters,including the weight of single seed,grains with or without seeds,seed numbers of seeded berry,the content of anthocyanin in the peel,total soluble solid and titrated acid in the juice were immediately measured after harvesting at the physiological mature degree.Thirty tiny flowers were harvested at full bloom stage with respect to all treatments.The paraffin method was used to cut the flower longitudinally and then the development of ovule and embryo sac was observed.As well as,the 30 small berries were collected at 3rd day after the full bloom from all treatments to calculate the number of pollen tube that had reached to the ovary of the respected flower.【Results】SM 200 mg·L^-1 alone or with the combination of GAs induced 100%seedlessness from 11 days before flowering to until 4 days after flowering.The only GAs application was less effective in the same period as mentioned above.The rate of seedlessness regarding SM(50,100 and 200 mg·L^-1 at the full bloom stage was 100%.The same rate was also observed with the treatment of SM 200 mg·L^-1+GAs 25 mg·L^-1 and SM 200 mg·L^-1+GAs 40 mg·L^-1.Whereas,the application of GAs and GA3(25 and 50 mg·L^-1)was more prominent and induced a high rate of seeded berries.Therefore,GAs can lead to the grapevine(Vitis vinifera×V.labrasca)seedlessness but cannot work in the case of the grape(Vitis vinifera L.).The application of SM 200 mg·L^-1 and SM 200 mg·L^-1+GAs 25 mg·L^-1 can not only lead to the‘Muscat Hamburg’grapevine(Vitis vinifera L.)seedlessness,but also improve the berry quality like total soluble solid.Paraffin sections showed that SM treatment inhibited the germination of stigma pollen grain and elongation of pollen tube at all parts of the pistil.However,the number of pollen tubes that reached the micropyle was still 0.8-1.4(control 3.8).The ovary had 4 ovules,which meant 3.2-6.4 pollen tubes reached to the micropyle of each ovary.As long as the ovule blastocyst was normal,it was impossible to become seedlessness.However,the SM treatment showed the normal ovule and embryo sac rate on the 11th and 7th days before flowering,which was lower than 16.6%(control 94.17%).Therefore,the dysplasia of ovule and embryo sac was the main reason for inducing seedlessness by the application of SM.【Conclusion】The SM 200 mg·L^-1 alone or with GAs 25 mg·L^-1 effectively induced seedless berrying in the grapevine(Vitis vinifera L.).The abnormal development of pistil ovules and embryo sacs after SM treatment was the main reason for the induction of seedlessness.