Preliminary Study on Water Physiological Characters of Male and Female Ginkgo biloba L.

[Objective] The experiment aimed to study the difference of water physiology of male and female Ginkgo biloba L. for discussing the strategy of water utilization as well as the important role of this difference during evolution process. [Method] The stem sap flow, stomatal conductance(Gs), transpiration rate(Tr) and water use efficiency (WUE) of male and female Ginkgo biloba L. were comparatively studied. [Result] The day-night processes of flow on male and female Ginkgo biloba L. were similar. The flow on male and female Ginkgo biloba L. in day were almost same while the flow at night on male Ginkgo biloba L. was bigger than that on female Ginkgo biloba L. The Tr and Gs of male and female Ginkgo biloba L. were high in morning and at night but low at noon ,while Tr and Gs of female Ginkgo biloba L. in morning and at night were higher than these of male Ginkgo biloba L. at the same time point. However, these indexes of female plant were lower than these of male plant from 11:00 to 14:00. WUE changing trends of male and female Ginkgo biloba L. were similar, while average water utilization rate of female Ginkgo biloba L. was slightly lower than that of male Ginkgo biloba L. [Conclusion] Compared with other companion plants, water physiology of male and female Ginkgo biloba L. had strong homoplasy. The phenomenon might be a survival strategy of dioecious plants under long term evolutionary pressure.

Female Plant Types of Ginkgo biloba L. in China

Ginkgo biloba is a dioecious and unique species within Ginkgo family and Ginkgo genus, but it shows a big variability. From 1950s, resources of female plants in China were investigated and collected, and the seed anatomical structure and morphological characters at different development stages were observed. According to the shape, length, width and thickness of ovule bracket and seed stone, as well as the characteristics of both sides and top of the stone, the female plants of Ginkgo biloba have been divided into five types, long-stone, Buddha-finger, horse-bell, mume-stone and round-stone. In addition, the important cultivars belonging to different types were also determined. The stone weight, index of stone shape, and contents of dry matter, amylose, amylopectin, starch, rough protein, soluble sugar and hydrocyanic acid in seed kernel of each type were measured, and the qualities of seed stone were appraised, which lays a foundation for the improvement and utilization of female plant resources in Ginkgo biloba.

Resistance of barley varieties to Heterodera avenae in the Qinghai–Tibet Plateau,China

The cereal cyst nematode,Heterodera avenae,is one of the most economically important pathogens impacting the worldwide production of cereals and is widely distributed in more than 16 regions in China.The present study used the numbers of nematodes inside the plant roots to evaluate the resistance/susceptibility of different subpopulations of barley Hordeum vulgare(QH2R,QH6R and TB2R)to H.avenae under field and pot conditions.Nematode development in two highly resistant varieties was also evaluated by in vivo experiment and microscopic observation.Analyses of 186selected varieties showed the numbers of susceptible varieties identified with the number of females/cysts per plant(NFP)method were significantly higher than those identified with the Pf/Pi ratio(PPR)method,which indicated that the NFP method rather than the PPR method is more reliable to evaluate the resistance of barley.The field and pot experiment results indicated that the QH2R subpopulation had lower females/cysts numbers than QH6R and TB2R subpopulations,and eight HR varieties(Sunong 7617,Sunong 7635,Dongyuan 87-14,Rudong 14-46,Rudong 87-57,Rudong 87-8-45,Rudong 88-14-2,and Rudong 88-67-1)were identified in QH2R,with the NFP numbers below 4.2.Further microscopic observation of nematode development suggested that H.avenae often penetrated less into highly resistant varieties(Sunong 7635 and Dongyuan 87-14)and more frequently failed to develop into females than the susceptible barleys.The promising resistant varieties identified in the present research might be helpful for breeders to develop CCN-resistant cultivars and control H.avenae populations effectively at low costs.