Photosynthesis, light energy partitioning, and photoprotection in the shade-demanding species Panax notoginseng under high and low level of growth irradiance
Photosynthesis, light energy partitioning, and photoprotection in the shade-demanding species Panax notoginseng under high and low level of growth irradiance
复制标题
高、低光照条件下喜荫植物三七的光合作用、光能分配及光保护
DOI：
10.1071/fp15283
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发表时间：
2016-01-01
影响因子：
3
通讯作者：
Zhang, Guang-Hui
中科院分区：
文献类型：
--
作者：
Chen, Jun-Wen;Kuang, Shuang-Bian;Zhang, Guang-Hui
研究了需用遮荫植物三七（Burkill）在光照梯度下的光能分配及其与光合作用的关系。在全光诱导叶片中，弱光植物PSII的实际光化学效率（F/F-m’）、电子传递速率（ETR）、非光化学猝灭（NPQ）和光化学猝灭（qP）较低；在模拟的日光斑下，完全适应黑暗的叶子也是如此。在不同的光强下，高光生长的植物表现出更高的光依赖性非光化学猝灭量子产率（phi(NPQ)）和PSII光化学量子产率（phi(PSII)），而荧光和本质热耗散量子产率（phi(f,d)）较小。在模拟晒斑下，高光植物的phi值（PSII）较大，phi值（f,d）较小。全光诱导叶片的净光合作用（A(net)）与phi（NPQ+f,d）呈正相关，净光合作用（A(net)）与phi（PSII）呈负相关；在完全适应黑暗的叶片中，A（net）与φ (NPQ+f,d)呈负相关，A（net）与φ (PSII)呈正相关。此外，在低光照植物中，更多的氮分配给了光捕获成分，而在高光照植物中，叶片的形态和解剖结构有助于减少光捕获。在高光生长的植物中，叶黄素色素池和去环氧化状态更大。抗氧化防御能力随着生长辐照度的增加而增强。总之，三七的研究结果表明，在强光照射下，高光生长的遮荫植物在激活NPQ组分的非净羧化过程中消耗了更多的电子，而低光生长的植物在强光照射下通过降低PSII光化学效率来保护光合机构免受光损伤。NPQ的ph依赖（qE）成分可能主导光保护，但NPQ也抑制光合作用通过光能竞争的增强。
Partitioning of light energy into several pathways and its relation to photosynthesis were examined in a shade-demanding species Panax notoginseng (Burkill) F.H.Chen ex C.Y.Wu & K.M.Feng grown along a light gradient. In fully light-induced leaves, the actual efficiency of PSII photochemistry (F/F-m'), electron transport rate (ETR), non-photochemical quenching (NPQ) and photochemical quenching (qP) were lower in low-light-grown plants; this was also the case in fully dark-adapted leaves under a simulated sunfleck. In response to varied light intensity, high-light-grown plants showed greater quantum yields of light-dependent non-photochemical quenching (phi(NPQ)) and PSII photochemistry (phi(PSII)) and smaller quantum yields of fluorescence and constitutive thermal dissipation (phi(f,d)). Under the simulated sunfleck, high-light-grown plants showed greater phi(PSII) and smaller phi(f,d). There were positive relationships between net photosynthesis (A(net)) and phi(NPQ+f,d) and negative relationships between A(net) and phi(PSII) in fully light-induced leaves; negative correlations of A(net) with phi(NPQ+f,d) and positive correlations of A(net) with phi(PSII) were observed in fully dark-adapted leaves. In addition, more nitrogen was partitioned to light-harvesting components in low-light-grown plants, whereas leaf morphology and anatomy facilitate reducing light capture in high-light-grown plants. The pool of xanthophyll pigments and the de-epoxidation state was greater in high-light-grown plants. Antioxidant defence was elevated by increased growth irradiance. Overall, the evidences from P. notoginseng suggest that in high-light-grown shade-demanding plants irradiated by high light more electrons were consumed by non-net carboxylative processes that activate the component of NPQ, that low-light-grown plants correspondingly protect the photosynthetic apparatus against photodamage by reducing the efficiency of PSII photochemistry under high light illumination, and that during the photosynthetic induction, the pH-dependent (qE) component of NPQ might dominate photoprotection, but the NPQ also depresses the enhancement of photosynthesis via competition for light energy.