沿海木麻黄套种条件下淡竹旱季光合水分生理特性

在秋冬旱季用Li-6400便携式光合仪测定木麻黄(Casuarina equisetifolia)林下套种的多年生淡竹(Phyllostachys glauca McClure)的光合特性和环境因子的日变化,并用回归分析研究光合特性对环境因子的响应.结果表明,在秋冬季,淡竹净光合速率(Pn)、蒸腾速率(Tr)曲线均呈"...

Photosynthetic Characteristics of Phyllostachys glauca McClure in Dry Season under Interplanting in Coastal Casuarina equisetifolia

In the current study,the diurnal variation of photosynthetic characteristics and environmental factors under natural light was studied in Phyllostachys glauca McClure intercropped in Casuarina equisetifolia forest by the Li-6400 portable photosynthetic system in autumn and winter.The response of photosynthetic characteristics in relation to environmental factors was analyzed by regression analysis.The results revealed that the net photosynthetic rate(Pn)and transpiration rate(Tr)both had a diurnal change with a single peak appearing in autumn and winter.The curve of Pn exhibited no phenomena of midday depression.Water use efficiency(WUE)presented a“double-peak”type.The values of Pn and WUE in winter were higher as compared to autumn whereas Tr values were lower.It showed the adaptation characteristics of higher photosynthetic rate,high WUE and low transpiration in winter.Average water potential(Ψw)(-8.094 MPa)of branches in winter was higher than those in autumn(-15.525 MPa),with insignificant variation.It showed a strong ability to absorb and reduce water loss of P.glauca McClure.The photosynthetic capacity of P.glauca McClure was closely related to environmental conditions.P.glauca McClure had different diurnal photosynthetic variation and different water utilization strategy in autumn and winter because of environmental factors such as temperature,water content and photosynthetic active radiation.The photosynthetic capacity in winter was higher than that of autumn.