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在人工气候箱中40℃高温下设计3个土壤水分梯度(分别为田间持水量的70%、55%、40%,即正常水分、轻度胁迫、重度胁迫),采用盆栽试验,模拟干热河谷车桑子(Dodonaea viscosa)、赤桉(Eucalyptus camaldulensis)、大叶相思(Acacia auriculiformis)苗期的光响应曲线和CO2响应曲线。结果表明:3个树种苗期的最大净光合速率均随水分胁迫加剧而下降,羧化效率、光呼吸速率均为先升后降,车桑子和赤桉各指标变化平缓,大叶相思对胁迫最为敏感。非直角双曲线模型较好地拟合了3个树种的光合特征参数。
Three soil moisture gradients (70%, 55%, 40% of the field water volume, respectively, that is normal water, mild stress, severe stress) were designed in the artificial climate chamber at 40 ℃. Pot experiments were conducted to simulate dry heat Light response curve and CO2 response curve at seedling stage of Dodonaea viscosa, Eucalyptus camaldulensis and Acacia auriculiformis were studied. The results showed that the maximum net photosynthetic rate of seedlings of three tree species decreased with the increase of water stress, and the carboxylation efficiency and photosynthetic respiration rate first increased and then decreased. The indexes of C. mongolicus and E. urophylla changed gently, Most sensitive to stress. The non-rectangular hyperbola model fitted well the photosynthetic parameters of three tree species.