为确定兔眼蓝浆果(Vaccinium ashei Reade)不同品种苗期的适宜施氮量,以兔眼蓝浆果早熟品种‘阿拉帕哈’(‘Alapha')、中熟品种‘园蓝'(‘Gardenblue')和晚熟品种‘芭尔德温'(‘Baldwin')的组培苗为实验材料,采用水培法研究了不同氮浓度(0、1、2 和4 mmol·L^-1 )对幼苗生长、根和叶中全氮含量、叶片光合生理特性的影响。结果表明:与对照(0 mmol·L^-1 氮)相比,经1、2 和4 mmol·L^-1  氮处理后3 个兔眼蓝浆果品种的单株茎叶干质量显著增加,根冠比显著降低;但品种‘园蓝'的单株根干质量显著高于对照,另2 个品种的单株根干质量与对照无显著差异。随着营养液中氮浓度的提高,3 个兔眼蓝浆果品种根的全氮含量及品种‘阿拉帕哈'叶的全氮含量均逐渐增加,且在4 mmol·L^-1  氮处理下最高;品种‘园蓝'和‘芭尔德温'叶的全氮含量呈先升高后降低的趋势,且均在2 mmol·L^-1  氮处理下最高;各处理组根和叶的全氮含量均显著高于对照。经1、2 和4 mmol·L^-1 氮处理后,3 个兔眼蓝浆果品种叶片的叶绿素a、叶绿素b 和总叶绿素含量以及PSII最大光化学效率(Fv / Fm )均呈先升高后降低的趋势,且均显著高于对照。各处理组中,品种‘园蓝'叶片的净光合速率(Pn)、气孔导度(Gs)、胞间CO2 浓度(Ci)和蒸腾速率(Tr)均显著高于对照;品种‘芭尔德温'叶片的Pn 值在4 mmol·L^-1 氮处理下显著低于对照,Gs 和Tr 值在2 mmol·L^-1  氮处理下显著高于对照,Ci 值与对照无显著差异;与对照相比,品种‘阿拉帕哈'叶片的Pn 值在1 和4 mmol·L^-1  氮处理下显著提高,Gs 值在1 mmol·L^-1  氮处理下显著提高,Tr 值在1 和2 mmol·L^-1  氮处理下显著提高,而Ci 值则在4 mmol·L^-1 氮处理下显著降低。综合分析结果显示:适度增施氮肥可提高兔眼蓝浆果不同品种幼苗的茎叶生长、改善其光合性能,但对根系生长无明显的促进作用。在营养生长期兔眼蓝浆果不同品种的需氮量存在差异,其中品种‘园蓝'更适宜高氮环境,而施用少量氮肥即可促进品种‘芭尔德温'和‘阿拉帕哈'幼苗地上部分生长。

In order to confirm suitable nitrogen application amount of different cultivars of Vaccinium ashei Reade during seedling period, taking tissue culture seedlings of early-maturing cultivar ‘Alapha’ middle-maturing cultivar ‘Gardenblue’and late-maturing cultivar ‘Baldwin’ of V. ashei as experimental materials, effects of different nitrogen concentrations (0, 1, 2 and 4 mmol·L^-1 ) on seedling growth, total nitrogen content in root and leaf and photosynthetic physiological characteristics of leaf were studied by hydroponics. The results show that compared with the control (0 mmol·L^-1 nitrogen), after treated by 1, 2 and 4 mmol·L^-1 nitrogen, shoot dry weight per plant of three cultivars of V. ashei increases significantly, root/ shoot ratio decreases significantly, but root dry weight per plant of cultivar ‘Gardenblue’is significantly higher than that of the control, that of other two cultivars has no significant difference with that of the control. With enhancing of nitrogen concentrations in nutrient solution, total nitrogen content in root of three cultivars of V. ashei and that in leaf of cultivar ‘Alapha’ increase gradually, with the highest in 4 mmol·L^-1 nitrogen treatment; total nitrogen content in leaf of cultivar ‘Gardenblue’and ‘Baldwin’appears the trend of firstly increasing and then decreasing, with the highest in 2 mmol·L^-1 nitrogen treatment; and total nitrogen content in root and leaf in all treatment groups is significantly higher than that of the control. After treated by 1, 2 and 4 mmol·L^-1 nitrogen, contents of chlorophyll a, chlorophyll b and total chlorophyll and the maximal photochemical efficiency of PSⅡ(Fv / Fm) of leaf of three cultivars of V. ashei all appear the trend of firstly increasing and then decreasing, and are significantly higher than those of the control. Net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci) and transpiration rate (Tr) of leaf of cultivar ‘Gardenblue’ in all treatment groups are significantly higher than those of the control. Pn value of leaf of cultivar ‘Baldwin'in 4 mmol·L^-1 nitrogen treatment is significantly lower than that of the control, its Gs and Tr values in 2 mmol·L^-1 nitrogen treatment are significantly higher than those of the control, and its Ci value has no significant difference with that of the control. Compared with the control, Pn value of leaf of cultivar ‘Alapha’in 1 and 4 mmol·L^-1  nitrogen treatments increases significantly, its Gs value increases significantly in 1 mmol·L^-1 nitrogen treatment, and its Tr value does in 1 and 2 mmol·L^-1  nitrogen treatments, while its Ci value decreases significantly in 4 mmol·L^-1  nitrogen treatment. The comprehensive analysis result shows that properly increasing nitrogen application can enhance stem growth and improve photosynthetic performance of seedling of different cultivars of V. ashei, but don't have obvious promotion of root growth. There is difference in nitrogen requirement among different cultivars of V. ashei at vegetative growth stage, in which, cultivar ‘Gardenblue’ is suitable for high nitrogen environment, while applying a few amount of nitrogen fertilizer can promote growth of above-ground part of seedling of cultivar ‘Baldwin’ and ‘Alapha’..