NaCl胁迫对杂交狗牙根品种‘苏植2号’和‘Tifgreen’生长及Na^+和K^+积累的影响

Effect of NaCl stress on growth and Na^+ and K^+ accumulation of cultivars ‘Suzhi No.2' and ‘Tifgreen' of hybrid bermudagrass (Cynodon dactylon×C.transvaalensis)

对0(对照)和20 g·L-1NaCl胁迫条件下杂交狗牙根(Cynodon dactylon×C.transvaalensis)品种‘苏植2号’(‘Suzhi No.2’)和‘Tifgreen’不同部位的生长状况以及Na+和K+积累的差异进行了研究,并分析了2个品种间Na+、K+转运调控机制的差异。结果显示:在NaCl胁迫条件下,2个品种的叶片相对枯黄率、地下茎和根系的相对干质量、叶片和根系的Na+含量和Na+/K+比以及钠钾选择性转运系数增加;修剪茎叶及冠层和地上部的相对干质量、植株相对总干质量以及叶片和根系的K+含量均降低,但茎叶含水量无显著变化。NaCl胁迫条件下,不同土层中2个品种的根系相对干质量均不同程度增加,且20~40和40~60 cm土层中根系干质量的增幅大于0~20 cm土层;在0~20 cm土层中2个品种根系的分配比例均有所降低,而在20~40和40~60 cm土层中则不同程度提高。与‘Tifgreen’相比,NaCl胁迫条件下‘苏植2号’叶片相对枯黄率、Na+含量和Na+/K+比更低,修剪茎叶及冠层和地上部的相对干质量、植株相对总干质量、叶片K+含量和钠钾选择性转运系数更高;在20~40和40~60 cm土层中‘苏植2号’根系相对干质量显著高于‘Tifgreen’,根系分配比例总体也高于‘Tifgreen’。综合比较结果表明:‘苏植2号’的抗盐性强于‘Tifgreen’,可能与其深层根系分配量更高和钠钾选择性转运能力较强有关。

Growth status and Na＋ and K＋ accumulation of different parts of cultivar ‘Suzhi No. 2’ and‘Tifgreen’ of hybrid bermudagrass （ Cynodon dactylon × C. transvaalensis） under conditions of 0 （control） and 20 g · L-1 NaCl （ stress treatment） were researched, and differences of Na＋ and K＋regulation mechanism between two cultivars were analyzed. The results show that under NaCl stress condition, relative percentage of leaf firing, relative dry weights of rhizome and root, Na＋ content and Na＋ / K＋ ratio in leaf and root and selective transportation coefficient of Na＋ and K＋ of two cultivars increase, relative dry weights of shoot clipping, crown and above-ground part, relative total dry weight of plant and K＋ content in leaf and root decrease, while there is no significant change in water content of shoot. Under NaCl stress condition, relative dry weight of root of two cultivars in different soil layers increases with different degrees, the increase range of root dry weight in soil layers of 20-40 and 40-60 cm is bigger than that in soil layer of 0-20 cm. Root distribution percentage of two cultivars in soil layers of 0-20 cm slightly decreases, while that in soil layers of 20-40 and 40-60 cm increases with different degrees. Compared with ‘Tifgreen’, relative percentage of leaf firing, Na＋ content and Na＋ / K＋ ratio in leaf of ‘Suzhi No. 2’ are lower, and relative dry weights of shoot clipping, crown and above-ground part, relative total dry weight of plant, K＋ content in leaf and selective transportation coefficient of Na＋and K＋ of ‘Suzhi No. 2’ are higher under NaCl stress condition. In soil layers of 20-40 and 40-60 cm, relative dry weight of root of ‘Suzhi No. 2’ is significantly higher and its root distribution percentage is generally higher than those of ‘ Tifgreen’. The comprehensive comparison result shows that salinity-tolerance of ‘Suzhi No. 2’ is higher than that of ‘ Tifgreen’, which might be associated with higher distribution amount of deep root and stronger selective transportation capacity of Na＋ and K＋.