Zhao Kuan, Wu Yanyou
School of Environment and Resources, Anqing Normal University, Anqing, P. R. China.
Key Laboratory of Modern Agricultural Equipment and Technology, Ministry of Education, Jiangsu University, Zhenjiang, P. R. China.
PLoS One. 2017 Jan 11;12(1):e0169812. doi: 10.1371/journal.pone.0169812. eCollection 2017.
Calcareous soils are characterized by low nutrient contents, high bicarbonate (HCO3-) content, and high alkalinity. The effects of HCO3- addition under zinc-sufficient (+Zn) and zinc-deficient (-Zn) conditions on the growth and photosynthetic characteristics of seedlings of two Moraceae species (Broussonetia papyrifera and Morus alba) and two Brassicaceae species (Orychophragmus violaceus and Brassica napus) were investigated. These four species were hydroponically grown in nutrient solution with 0 mM Zn (-Zn) or 0.02 mM Zn (+Zn) and 0 mM or 10 mM HCO3-. The photosynthetic response to HCO3- treatment, Zn deficiency, or both varied according to plant species. Of the four species, Broussonetia papyrifera showed the best adaptability to Zn deficiency for both the 0 mM and 10 mM HCO3- treatments due to its strong growth and minimal inhibition of photosynthesis and photosystem II (PS II). Brassica napus was sensitive to Zn deficiency, HCO3- treatment, or both as evidenced by the considerable inhibition of photosynthesis and high PS II activity. The results indicated different responses of various plant species to Zn deficiency and excess HCO3-. Broussonetia papyrifera was shown to have potential as a pioneer species in karst regions.
石灰性土壤的特点是养分含量低、碳酸氢根（HCO₃⁻）含量高且碱度高。研究了在锌充足（+Zn）和锌缺乏（-Zn）条件下添加HCO₃⁻对两种桑科植物（构树和桑树）和两种十字花科植物（诸葛菜和甘蓝型油菜）幼苗生长和光合特性的影响。这四种植物在含有0 mM锌（-Zn）或0.02 mM锌（+Zn）以及0 mM或10 mM HCO₃⁻的营养液中进行水培。植物对HCO₃⁻处理、锌缺乏或两者的光合响应因植物种类而异。在这四种植物中，构树在0 mM和10 mM HCO₃⁻处理下对锌缺乏均表现出最佳适应性，因其生长旺盛且光合作用和光系统II（PS II）受到的抑制最小。甘蓝型油菜对锌缺乏、HCO₃⁻处理或两者均敏感，表现为光合作用受到显著抑制且PS II活性较高。结果表明不同植物种类对锌缺乏和过量HCO₃⁻有不同的响应。构树被证明有潜力成为喀斯特地区的先锋物种。
