Bauerle William L, Hazlett Michael
Department of Horticulture and Landscape Architecture, Colorado State University, Fort Collins, CO 80523, USA.
Plants (Basel). 2023 May 19;12(10):2030. doi: 10.3390/plants12102030.
The primary metabolism and respiration of the hop strobilus has not been quantified in response to daily temperature fluctuations. The objective of this study was to assess strobilus gas exchange, specifically the response to temperature fluctuations. Hop strobilus were measured under controlled environment conditions to assess the organ's contribution to carbon assimilation and respiration during the maturation phase. Strobilus-specific daily carbon budgets were estimated in response to temperature fluctuation. The optimal temperature for net carbon gain occurred at 15.7 °C. Estimated strobilus carbon uptake decreased approximately 41% per 5 °C increase in temperature above 20 °C. Daily temperatures within 10-27 °C resulted in a net positive strobilus daily carbon balance, whereas temperature increases beyond 27 °C increasingly exhaust strobilus carbon reserves. The Q temperature coefficient (the rate respiration increases every 10 °C rise in temperature) approximately doubled per 10 °C rise in temperature from 7-40 °C (1.94-2) with slightly reduced values at lower temperatures. In conclusion, we show that photosynthetically active bracts maintain a positive strobilus carbon balance at moderate temperatures and as mean daily temperatures progressively exceed 27 °C, strobilus net carbon reserves are precipitously exhausted due to ever-increasing respiration rates.
尚未对酒花球果的主要代谢和呼吸作用随每日温度波动的情况进行量化。本研究的目的是评估球果的气体交换，特别是对温度波动的响应。在可控环境条件下对酒花球果进行测量，以评估该器官在成熟阶段对碳同化和呼吸作用的贡献。针对温度波动估计了球果特定的每日碳预算。净碳增益的最佳温度出现在15.7℃。温度在20℃以上每升高5℃，估计的球果碳吸收量大约减少41%。10 - 27℃范围内的日温度导致球果每日碳平衡呈净正增长，而温度升高超过27℃会越来越多地耗尽球果的碳储备。温度系数Q（温度每升高10℃呼吸速率增加的比率）在7 - 40℃范围内每升高10℃大约翻倍（从1.94增至2），在较低温度下数值略有降低。总之，我们表明，在适度温度下，具有光合活性的苞片可维持球果的正碳平衡，并且随着日平均温度逐渐超过27℃，由于呼吸速率不断增加，球果的净碳储备会急剧耗尽。
