Plant Growth and Photosynthesis Response to Low Potassium Conditions in Three Lettuce (Lactuca sativa) Types
Plant Growth and Photosynthesis Response to Low Potassium Conditions in Three Lettuce (Lactuca sativa) Types
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三种生菜（Lactuca sativa）类型对低钾条件的植物生长和光合作用响应
DOI：
10.2503/hortj.okd-008
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
T. Maruo
中科院分区：
文献类型：
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作者：
Geng Zhang;M. Johkan;M. Hohjo;S. Tsukagoshi;T. Maruo
慢性肾脏病已成为全球主要的公共卫生问题。研究了低钾条件下3种不同形态特征的莴苣（Lactucasativa）植株生长和光合特性的差异，为改进低钾栽培方法提供依据。采用含4、2、1 me·L−1 K+的半浓度恩施配方营养液水培生菜。3种类型生菜的产量和相对生长速率（RGR）均以1 me·L-1 K+处理最低。在绿色叶莴苣中，净同化率（NAR）和叶面积比（LAR）的降低导致RGR下降。在波士顿莴苣和长叶莴苣中，RGR的降低主要是由于LAR的降低，并且在较小程度上由NAR引起。减少钾营养液中有一个更大的影响，成熟的叶片比新扩展的叶片为所有三种生菜类型。在绿色叶莴苣和波士顿莴苣中，成熟叶片的光合速率显着降低，减少钾处理，与一个稳定的或逐渐增加的胞间CO2浓度，这表明非气孔因素抑制光合作用。在长叶莴苣，光合速率的影响较小的营养液中的钾水平降低，和观察到的单位面积的叶质量的显着增加可能有助于维持光合作用的叶片。3种生菜成熟叶片光合速率的下降趋势与叶片含钾量的下降趋势相似，但影响光合速率下降的因素不同。
Chronic kidney disease has become a major public health problem worldwide. The aim of this study was to investigate the differences in plant growth and photosynthesis among three lettuce (Lactuca sativa) types with different morphological characteristics under low potassium conditions, providing information for improving the method of low-potassium lettuce culture. Lettuce was hydroponically grown in half-strength Enshi formula nutrient solution containing 4, 2, or 1 me·L−1 K+. The plant yield and relative growth rates (RGR) of all three lettuce types were lowest under a treatment with 1 me·L−1 K+. In green leaf lettuce, reductions in both the net assimilate rate (NAR) and leaf area ratio (LAR) led to a decline in RGR. In Boston lettuce and romaine lettuce, the reduction of RGR was mainly due to a reduction in LAR, and to a lesser extent caused by NAR. Reduced potassium in the nutrient solution had a greater effect on mature leaves than on newly expanded leaves for all three lettuce types. In green leaf lettuce and Boston lettuce, photosynthetic rates of mature leaves significantly decreased under reduced potassium treatments, with a steady or gradually increased intercellular CO2 concentration; this indicated that non-stomatal factors suppressed photosynthesis. In romaine lettuce, the photosynthetic rate was less influenced by reduced potassium levels in the nutrient solution, and the significant increase observed in leaf mass per area might contribute to maintaining photosynthesis in the leaf. The decrease in photosynthesis in mature leaves exhibited a similar trend to the decreased potassium content in the leaves within the three lettuce types, but the factor related to the reduction of photosynthesis was different.