Zhang Hui-Hui, Zhang Xiu-Li, Li Xin, Ding Jun-Nan, Zhu Wen-Xu, Qi Fei, Zhang Ting, Tian Ye, Sun Guang-Yu
College of Life Science, Northeast Forest University, Harbin 150040, China.
Ying Yong Sheng Tai Xue Bao. 2012 Mar;23(3):625-31.
Taking 1-year old Morus alba variety 'Qinglong' seedlings as test materials, this paper studied their growth and photosynthetic characteristics under the stresses of different concentration neutral salt NaCl and alkali salt Na2CO3. Salt stresses decreased the plant height and the leaf number, biomass, and photosynthetic capacity of the seedlings markedly. With increasing concentration Na+, the leaf stomatal conductance, transpiration rate, net photosynthetic rate, actual photochemical efficiency, electron transport rate, and photochemical quenching (qP) decreased obviously, the energy dissipation rate increased, and the light use efficiency and photosynthetic capacity dropped down. At low concentrations Na+ (< 150 mmol x L(-1)), the seedlings growth and leaf photosynthetic capacity were slightly inhibited, and the adaptability of the seedlings to the salt stresses increased via the increase of root/shoot ratio. However, this protection mechanism was impaired by increasing salt concentration. Na2CO3 stress (Na+ concentration > 50 mmol x L(-)) had stronger inhibitory effects on the seedlings growth and leaf photosynthetic capacity, and the effect increased with increasing Na+ concentration. It was concluded that at Na+ concentration < 150 mmol x L(-1), the photosynthetic adaptability of M. alba to neutral salt stress was mainly dependent on the plant morphology and photosynthetic metabolism, but at Na+ concentration > 150 mmol x L(-1), the photosynthetic adaptability of M. alba to alkali salt stress was mainly dependent on the photosynthetic metabolism.
以1年生桑品种‘青龙’幼苗为试验材料，研究了其在不同浓度中性盐NaCl和碱性盐Na2CO3胁迫下的生长和光合特性。盐胁迫显著降低了幼苗的株高、叶片数、生物量和光合能力。随着Na+浓度的增加，叶片气孔导度、蒸腾速率、净光合速率、实际光化学效率、电子传递速率和光化学猝灭（qP）明显降低，能量耗散率增加，光能利用效率和光合能力下降。在低浓度Na+（<150 mmol·L-1）下，幼苗生长和叶片光合能力受到轻微抑制，幼苗通过增加根冠比提高对盐胁迫的适应性。然而，这种保护机制会随着盐浓度的增加而受损。Na2CO3胁迫（Na+浓度>50 mmol·L-）对幼苗生长和叶片光合能力的抑制作用更强，且随着Na+浓度的增加而增强。研究得出，在Na+浓度<150 mmol·L-1时，白桑对中性盐胁迫的光合适应性主要依赖于植株形态和光合代谢，但在Na+浓度>150 mmol·L-1时，白桑对碱性盐胁迫的光合适应性主要依赖于光合代谢。
