PHOTOSYNTHETIC RESPONSES OF ZOSTERA-MARINA L (EELGRASS) TO INSITU MANIPULATIONS OF LIGHT-INTENSITY
PHOTOSYNTHETIC RESPONSES OF ZOSTERA-MARINA L (EELGRASS) TO INSITU MANIPULATIONS OF LIGHT-INTENSITY
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DOI：
10.1007/bf00384478
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发表时间：
1982-01-01
期刊：
影响因子：
2.7
通讯作者：
ALBERTE, RS
中科院分区：
文献类型：
--
作者：
DENNISON, WC;ALBERTE, RS
1981年8月期间，在美国马萨诸塞州伍兹霍尔的大港湾的一片鳗草床中，通过对光子通量密度的操控，研究了温带海草大叶藻（Zostera marina L.）的光合反应。在鳗草床的浅水区（1.3米）和深水区（5.5米）设置了太阳反射器和遮光屏，以增加（+35%到 +40%）和降低（-55%）环境光子通量密度。确定了一天中光强超过大叶藻光补偿点（Hcomp）和光饱和点（Hsat）的时间段，以评估反射器和遮光屏的影响。深水区遮光屏处的Hcomp和Hsat时间段受影响最大；Hcomp减少了11%，Hsat减少了52%。在三组为期1 - 2周的实验结束时，测定了光饱和光合速率、暗呼吸速率、叶片叶绿素含量、叶绿素a/b、PSUO₂大小、光合单位（PSU）密度、叶面积、比叶面积、叶片周转时间和叶片生产率。在浅水区，所测参数均未受到光子通量密度操控的影响；然而，在深水区，遮光屏下的叶片生产率显著降低，反射器处的叶绿素a/b比值较高。大叶藻对光照条件短期变化的调节主要通过叶片生产率实现。此外，补偿或饱和光子通量密度时间段内最显著的变化对所测光合反应的影响最大。
Photosynthetic responses of the temperature seagrass, Z. marina L., were examined by manipulations of photon flux density in an eelgrass bed in Great Harbor, Woods Hole, [Massachusetts, USA], during Aug. 1981. Sun reflectors and light shading screens were placed at shallow (1.3 m) and deep (5.5 m) stations in the eelgrass bed to increase (+35% to +40%) and decrease (-55%) ambient photon flux densities. The portion of the day that light intensities exceeding the light compensation point for Z. marina (Hcomp) and the light saturation point (Hsat) were determined to assess the impact of the reflectors and shades. The Hcomp and Hsat periods at the deep station shading screen were most strongly affected; Hcomp was reduced by 11% and Hsat was reduced by 52%. Light-saturated photosynthetic rates, dark respiration rates, leaf chlorophyll content, chlorophyll a/b, PSUO2 size, PSU [photosynthetic unit] density, leaf area, specific leaf area, leaf turnover times and leaf production rates were determined at the end of 3 sets of 1- to 2-wk experiments. None of the measured parameters were affected by the photon flux density manipulations at the shallow station; however, at the deep station, leaf production rates were significantly reduced under the shading screen and chlorophyll a/b ratios were higher at the reflector. Adjustment to short-term changes in light regime in Z. marina is lragely by leaf production rates. Further, the most dramatic changes in the periods of compensating or saturating photon flux densities had the greatest impact on the measured photosynthetic responses.