半红树植物黄槿的生态生物学特性研究

黄槿是一种具有重要生态、药用和观赏价值的半红树植物,在海岸生态系统中发挥重要作用。对其生态及生物学特性进行研究表明:黄槿属典型阳生性植物,具有较高的光合潜能,适于在热带亚热带地区光照充足的环境中生长。其叶绿素荧光的光合电子传递速率-光响应曲线(RLC)显示,黄槿的相对电子传递速率(rETR)随光合有效辐射(PAR)的升高而逐渐增加,并在PAR 2 751μmol.m-2.s-1时达到最大值,说明其光合系统II在强光照下也能保持较高的电子传递效率。黄槿叶绿素荧光参数显示其具有较高的能量利用效率,叶绿素a/b值(2.44∶1)略低于理论值(3∶1)。黄槿对营养元素的利用率较高,植株体内N、P、K、Ca、Na、Mg的加权平均养分含量分别为1.23%、0.23%、1.34%、0.42%、0.24%、0.41%。P含量偏低,在其栽培过程中应及时补充P元素。该研究结果将对黄槿的引种、栽培及开发利用提供重要的理论依据。

Ecological and biological characteristics of Hibiscus tiliaceus,a mangrove associate in China

Hibiscus tiliaceus is a mangrove associate species with high medicinal,ecological and ornamental values and plays an important role in coastal ecosystem.The study on the ecological and biological characteristics of H.tiliaceus showed that it was a typical heliophyte with high photosynthetic capacity and preferred to grow under sunny condition in tropical and subtropical regions.The chlorophyll fluorescence rapid light response curves of H.tiliaceus showed that relative electron transport rate(rETR)increased with elevated photosynthetically active radiation(PAR)and reached its maximum value at 2 751 μmol·m-2·s-1,indicating that its photosystem Ⅱ maintained relatively high electron transport rate in high radiation condition.Measurement of chlorophyll fluorescence parameters showed that it had a relatively high level of energy use efficiency.The chlorophyll a/b ratio(2.44∶1) was slightly lower than theoretic value(3∶1).H.tiliaceus had a high level of nutrient utilization efficiency.The weighted nutrient concentrations of N,P,K,Ca,Na and Mg in H.tiliaceus were 1.23%,0.23%,1.34%,0.42%,0.24% and 0.41%,respectively.The concentration of phosphorus(P)in the plant was relatively low,so it should be added in cultivation.The results from the current study would be very useful for introduction,cultivation,exploitation and utilization of H.tiliaceus.