The Ecophysiological Characteristics of Bamboo Seedlings

Abstract

The study on ecophysiological characteristics of 7 bamboo species were carried out at the Royal Agricultural Station Pang Da, Chiang Mai. The seedlings were planted in 20-cm-diameter pots. Net photosynthetic rates of all seedlings were measured using Portable Photosynthesis System (ADC - LCA4). Bamboo water uses were measured gravimetrically, and stomatal resistances were measured using Steady State Porometer. The net photosynthetic rates of Dendrocalamus latiflorus propagated by seeds and stumps were highest in the morning and showed substantial diurnal variation, particularly D. latiflorus from seeds. D. asper showed the weakest variation of net photosynthetic rates between morning and afternoon. Net photosynthetic rates of all bamboo species were decreased in the afternoon.

The highest water use of bamboo seedlings was found in D. latiflorus (from stump), Bambusa sp., and D. latiflorus (from seed) with the value of 2.02, 2.01, and 1.73 mm day-1, respectively. Bamboo water stress can be classified into 3 groups, including severe water stress (D. latiflorus), intermediate water stress (B. oldhamii and Phyllostachys makinoi) and mild water stress (Bambusa sp., Thyrsostachys siamensis, D. hamiltonii, and D. asper). Most bamboo species showed distinguishable water stress at the 4th day of stress period. Variations of stomatal resistance were similar for all species, the values were higher in the morning, then decreased through the late morning and early afternoon, and increased again in the evening. Bambusa sp., D. latiflorus (from stump) and D. hamiltonii showed the distinguishable responses in stomatal resistance at the 4th day of stress period. The result implied that bamboo seedlings must not be kept unwatering more than 4 days, since the physiological processes may be affected.

Keywords: bamboo, ecophysiological characteristic, photosynthesis, water use