科尔沁沙地几种常见植物对风胁迫的生理响应

风在自然界很常见,对植物也有很大影响,尤其在多风沙的干旱、半干旱地区。本研究以科尔沁沙地4种常见植物:沙米、大果虫实、胡枝子和马唐为对象,采用便携式风洞对以上4种植物进行不同吹风强度(4 m·s-1和8 m·s-1)和吹风时间(20~120 min)的处理,同时利用Li-6400光合作用测定仪对植物的净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Ts)的变化进行测定,以研究这4种植物对风胁迫的生理响应。结果表明:4种植物的Pn、Gs和Ts均随着风速的增大和吹风时间的加长而显著降低。在4 m·s-1风速下,4种植物的Pn、Gs和Ts在吹风结束时分别降低了47.2%~89.3%,49.4%~90.1%,45.7%~86.5%。同样,在8 m·s-1风速下,4种植物Pn、Gs和Ts的降幅分别为59.2%~91.3%,47.3%~93.5%,69.5%~91.8%。除了胡枝子的Gs外,其他所测指标在8 m·s-1风速下的降幅均大于在4 m·s-1风速下。4种植物的水分利用效率(WUE)在吹风的初期均有所升高,但当吹风时间超过60 min后则普遍开始下降,这说明固沙植物对短时风胁迫具有一定的适应性。

Physiological Response to Wind of Some Common Plants in Horqin Sand Land

Wind exerts influence on plant, especially in arid and semiarid regions. In the portable wind tunnel, the net photosynthetic ratio(Pn), stomata conductance(Gs) and transpiration ratio(Ts) of four kinds common plants (Agriophyllum squarrosum, Corispermum macrocarpum, Lespedeza davurica and Digitaria cilliaris) in Horqin Sand Land were measured with a Li-6400 under different air velocities (4 and 8 m·s-1) and blowing duration (20 to 120 min). The results showed that wind made Pn, Gs and Ts decreased significantly with elevated wind levels and blowing duration. At the air velocity of 4 m·s-1, the Pn, Gs and Ts of plants inside the wind tunnel were 47.2%~89.3%, 49.4%~90.1% and 45.7%~86.5% lower than the beginning, respectively. Similarly, Pn, Gs and Ts remained lower as a result of 8 m·s-1 air current, and the decreasing extent was 59.2%~91.3%, 47.3%~93.5% and 69.5%~91.8% respectively. All the indices measured at the air velocity of 8 m·s-1 decreased more than that at the air velocity of 4 m·s-1 except the Gs of Lespedeza davurica. Furthermore, the water use efficiency (WUE) presented evident uptrend at the beginning of wind treatment, suggesting that sand-fixing plants have adaptability to the wind current in short time. However, continuous strong wind current more than 60 min would cause the WUE turning to drop.