Characteristics of sun- and shade-adapted populations of an endangered plant Primulina tabacum Hance
Characteristics of sun- and shade-adapted populations of an endangered plant Primulina tabacum Hance
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DOI：
10.1007/s11099-010-0066-8
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发表时间：
2010-12-01
期刊：
影响因子：
2.7
通讯作者：
Guan, L. L.
中科院分区：
文献类型：
--
作者：
Liang, K. M.;Lin, Z. F.;Guan, L. L.
报春花是我国南方喀斯特石灰岩地区富钙氮土壤中的一种濒危多年生草本植物。对生长在洞穴边缘地带（TZ点，极低光照）、洞穴入口（EZ点，低光照）和开阔地带（OA点，高光照）的烟粉虱种群的形态、超微结构和生理特性进行了研究。在OA试验点，将烟草植株暴露于强光（635 μ mol m（-2）s（-1）的平均每日光合有效辐射）和干旱胁迫下，并表现出使光捕获和水分损失最小化的性状。与EZ和TZ点相比，OA点的叶片较厚，气孔和短柔毛密度较高，栅栏/海绵比、净光合速率的光饱和速率（P（max））、生物量、非光化学猝灭系数（NPQ）和光饱和点（LSP）较高，但每个叶绿体基粒数较少，类囊体堆积较少。与此相反，生长在洞穴附近的普通烟草：EZ（平均日辐照度59 μ mol m（-2）s（-1））和TZ（平均日辐照度11 μ mol m（-2）s（-1））显示出典型的最佳光捕获的阴影适应特性。这种对光照和遮荫的适应性特征表明，普通烟草对不同的环境有不同的科普策略，但这些策略是否反映了遗传选择或物候可塑性尚待确定。这种生理和形态性状的变异性对于烟草在异质光照条件下的存活是重要的。
Primulina tabacum Hance is an endangered perennial herb distributed in calcium-rich and nitrogen-limited soil of the karst limestone areas in southern China. The morphological, ultrastructural, and physiological traits were determined for P. tabacum populations growing in three different environment conditions: twilight zone of a cave (site TZ, extremely low light intensity), at a cave entrance (site EZ, low light intensity), and in an open area (site OA, high light intensity). At site OA, P. tabacum plants were exposed to high light (635 mu mol m(-2) s(-1) of mean daily photosynthetically active radiation) with drought stress, and expressed traits to minimize light capture and water loss. Compared to plants at sites EZ and TZ, those at site OA had thicker leaves with higher densities of stomata and pubescence, higher palisade/spongy ratio, higher light-saturated rate of net photosynthetic rate (P (max)), higher biomass, higher non-photochemical quenching coefficient (NPQ), and higher light saturation point (LSP) but fewer grana per chloroplast and less thylakoid stacking per granum. In contrast, P. tabacum growing at the cave vicinities: EZ (mean daily irradiance 59 mu mol m(-2) s(-1)) and TZ (mean daily irradiance 11 mu mol m(-2) s(-1)) showed typical shade-adapted characteristics for optimum light capture. The presence of sun- and shade-adapted characteristics indicates that P. tabacum has different strategies to cope with different environments but whether these strategies reflect genetic selection or phenological plasticity is yet to be determined. Such variability in physiological and morphological traits is important for the survival of P. tabacum in heterogeneous light conditions.