Servaites J C, Geiger D R
Department of Biology, University of Dayton, Dayton, Ohio 45469.
Plant Physiol. 1974 Oct;54(4):575-8. doi: 10.1104/pp.54.4.575.
The mass transfer rate of (14)C-sucrose translocation from sugar beet (Beta vulgaris, L.) leaves was measured over a range of net photosynthesis rates from 0 to 60 milligrams of CO(2) decimeters(-2) hour(-1) under varying conditions of light intensity, CO(2) concentration, and O(2) concentration. The resulting rate of translocation of labeled photosynthate into total sink tissue was a linear function (slope = 0.18) of the net photosynthesis rate of the source leaf regardless of light intensity (2000, 3700, or 7200 foot-candles), O(2) concentration (21% or 1% O(2)), or CO(2) concentration (900 microliters/liter of CO(2) to compensation concentration). These data support the theory that the mass transfer rate of translocation under conditions of sufficient sink demand is limited by the net photosynthesis rate or more specifically by sucrose synthesis and this limitation is independent of light intensity per se. The rate of translocation was not saturated even at net photosynthesis rates four times greater than the rate occurring at 300 microliters/liter of CO(2), 21% O(2), and saturating light intensity.
在不同的光照强度、二氧化碳浓度和氧气浓度条件下，测量了甜菜（Beta vulgaris, L.）叶片中¹⁴C - 蔗糖转运的质量传递速率，净光合速率范围为0至60毫克二氧化碳·分米⁻²·小时⁻¹。无论光照强度（2000、3700或7200英尺烛光）、氧气浓度（21%或1% O₂）或二氧化碳浓度（900微升/升二氧化碳至补偿浓度）如何，标记光合产物向总库组织的转运速率是源叶净光合速率的线性函数（斜率 = 0.18）。这些数据支持了这样一种理论，即在库需求充足的条件下，转运的质量传递速率受净光合速率限制，或者更具体地说受蔗糖合成限制，并且这种限制与光照强度本身无关。即使在净光合速率比300微升/升二氧化碳、21% O₂和饱和光照强度下的速率大四倍时，转运速率也未达到饱和。
