The experiments were conducted in an 8 years old grape orchard, ‘Red Globe’, to study the effect of sunlight, air temperature, wind speed and other factors on grape berry sunburn. The results showed that the higher temperature on fruit surface was the direct factor inducing grape sunburn. The threshold temperatures to induce sunburn ranged from 42.0℃ to 42.8℃(average temperature was 42.3℃) during fruit fast swell stage. It would reach to maximum after 12 minutes if the berries were suddenly exposed to the sunlight. The excessive sunlight increased both air temperature and fruit surface temperature. Therefore, excessive sunlight was the most important factor causing grape sunburn. The illumination per 10 000 lx could add about 1℃ on fruit surface at noon of a shiny and windless day in summer. The fruit surface temperature was significantly higher on the days without wind than when the wind speed was 1.5m﹒s-1. When wind speed approached 3.0m/s, the fruit surface temperature decreased to a very low level within 6 minutes. The higher relative humidity increased grape sunburn under the same light and temperature conditions.
The mature fruits of post-harvest ‘Jingmi’grape were irradiated by the dosage of 3.6 kJ·m-2 ultraviolet C (UV-C) and then incubated 24 hours in dark at 25 ℃. The UV-C irradiated berries and control berries were stored at 0 ℃ and 25 ℃. The berries was sampled at 0, 0.5, 1, 2, 3, 7, 10,14, 24 and 34 d. Resveratrol and piceid content in grape berries was determined by HPLC. The results showed: Trans-resveratrol (trans-Res) and cis-Piceid (cis-PD) content in grape berries skin was significantly increased when treated by UV-C irradiation and then incubated 24 h in dark at 25 ℃, but trans-Piceid (trans-PD) content in grape berries skin was not significantly increased. Storage temperature played an important role on the level of Res and its glycosides by UV-C irradiation treatment. cis-Resveratrol (cis-Res)could not detected in skin of UV-C irradiated berries and control berries.trans-Res, trans-PD and cis-PD content of control grape berries skin was low and stable under 25 ℃ and 0 ℃, while UV-C irradiated berries skin was higher than control at mostly sampling time and changed sharply.
The experiment was conducted with peach ( Prunus persica L. ) ‘Jingyu’and ‘Okubo’fruits. The sugar content was measured in peach endocarp during the course of the cell division and pit hardening, analyzing the change of sugar accumulation, observing the development of endocarp cell wall through the transmission electron microscope (TEM) and detecting the p rogress of the its lignin deposition by staining with phloroglucinol - HCl reagent. The results showed the cell in the peach endocarp divided continuously, the primary cell wall expanding, the cell organ marginalizing gradually, which was the stage of
sugar rap id accumulation, before 40 days after full blooming. The internal part began red after more than 40 days, the lignin deposition finished after 15 days or so, sugar accumulation and dynamic metabolism decreased rapidly, which showed lignin deposition occurred after the peak of sugar accumulation. Its content had an important effect on endocarp development.
In this paper, the polyp loidswere induced by low concentration of colchicin and oryzalin solution at early develop ing embryo in order to research and produce a new sort of germplasm of autotetrap loid in Dendrobium hybrida orchilds. During the process, the cross-pollinated seeds in the same plant were utilized as materials to obtain the PLBs through seed non-symbiotic germination and induction which app lied in the process of tissue culture. The results revealed that the rate of tetraploid was over 90% when treated with
0.01% colchicine and 5 mg·L - 1 oryzalin during 8 - 10 days. Moreover mosaic was not found in the doubling materials in the whole experiment. Compared with diploid, the tetraploid plantlets have always been more stout, the leaf are dark green and wide-thick