Abstract Hazelnut (Corylus spp.) flowering occurs during late winters and early spring which coincides with erratic fluctuating weather patterns. Irregular and reduced precipitation, especially in the form of snow, is assumed to dictate poor flowering and enhanced injury to catkins, especially in the sourced cultivars of interest to growers. We investigated the effect of water (precipitation received as rain and or snow) percolation during snowmelt period using phenological endpoints such as female flower ratio, bud position of female flower occurrence, and catkin dehiscence in sourced and locally adapted cultivars. These reproductive events were also analyzed for biochemical endpoints such as the concentrations of tryptophan, serotonin and melatonin in temporally collected bud or catkin samples. In addition, the yield responses of the tagged twigs were tracked and analyzed. When snow was consistently removed from the root zone (NS) or when a prior placed plastic sheet (P) disallowed water percolation, the percentage of female flowers and apical dominance declined in the sourced cultivars suggesting an erratic gradient between aerial and belowground temperature. The presence of snow cover resulted in increased probability of female flowers from dormant buds in sourced cultivars. Tryptophan was found to accumulate in the dormant buds of sourced cultivars where snow was not disturbed, while serotonin concentrations were significantly higher in NS and P treatments. Melatonin concentrations were notably high in dormant flower and vegetative buds of locally adapted cultivars especially subjected to P treatment. The biochemical markers may not only assist in identifying cold tolerance but also reveal abiotic stress negating responses modulated by relative concentrations of these molecules. Our results demonstrate that ideal conditions of good precipitation, especially as snow, would not only blanket to provide thermoregulation but also maintain the sensitive gradient on which temperate trees rely to break dormancy and initiate flower development. These findings also suggest that the use of horticultural alternatives such as thermal mulch could be an option for mitigating adverse conditions of reduced water percolation which affect reproductive physiology of hazelnut.

中文翻译：

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水分渗透在榛子生殖生理学中的作用（Corylus spp.）

摘要 榛子 (Corylus spp.) 开花发生在晚冬和早春，这与不稳定的波动天气模式相吻合。不规则和减少的降水，特别是以雪的形式，被认为导致开花不良和对柳絮的伤害增加，特别是在种植者感兴趣的来源品种中。我们使用物候终点（如雌花比例、雌花出现的芽位置以及来源和当地适应品种的柳絮开裂）研究了融雪期间水（以雨或雪形式接收的降水）渗透的影响。还分析了这些生殖事件的生化终点，例如临时收集的芽或柳絮样本中色氨酸、血清素和褪黑激素的浓度。此外，跟踪和分析标记树枝的产量反应。当雪从根区 (NS) 持续去除或当预先放置的塑料片 (P) 不允许水渗透时，来源品种中雌花的百分比和顶端优势下降，表明空中和地下温度之间存在不稳定的梯度。积雪的存在导致来源栽培品种的休眠芽中雌花的可能性增加。发现色氨酸在未受雪干扰的来源栽培品种的休眠芽中积累，而在 NS 和 P 处理中血清素浓度显着更高。当地适应栽培品种的休眠花和营养芽中的褪黑激素浓度特别高，特别是经过磷处理。生化标记不仅可以帮助确定耐寒性，还可以揭示由这些分子的相对浓度调节的非生物胁迫否定反应。我们的结果表明，良好降水的理想条件，尤其是雪，不仅可以提供温度调节，还可以维持温带树木打破休眠和启动花朵发育所依赖的敏感梯度。这些发现还表明，使用热覆盖等园艺替代品可能是减轻影响榛子生殖生理的水渗透减少的不利条件的一种选择。我们的结果表明，良好降水的理想条件，尤其是雪，不仅可以提供温度调节，还可以维持温带树木打破休眠和启动花朵发育所依赖的敏感梯度。这些发现还表明，使用热覆盖等园艺替代品可能是减轻影响榛子生殖生理的水渗透减少的不利条件的一种选择。我们的结果表明，良好降水的理想条件，尤其是雪，不仅可以提供温度调节，还可以维持温带树木打破休眠和启动花朵发育所依赖的敏感梯度。这些发现还表明，使用热覆盖等园艺替代品可能是减轻影响榛子生殖生理的水渗透减少的不利条件的一种选择。