Growth, photosynthesis, and Na ? , K ? , Ca 2? , and Mg 2? distributions were examined in two-year-old hydroponically cultured Populus nigra and Populus alba cuttings exposed to salt stress (0, 50, or 100 mM NaCl) for four or six weeks and to nonaeration stress for one or three weeks, followed by a three-week aeration period in 2/ 5 Hoagland solution. Salt stress with 100 mM NaCl totally inhibited height increase in P. nigra cuttings. Combined salinity and nonaeration inhibited height increase to a greater degree than either stress alone in both species. Simple salt stress did not affect diameter increase in P. alba, whereas combined high salinity (100 mM NaCl) and nonaeration inhibited diameter increase. Growth and biomass accumulation were more sensitive to salt stress in P. nigra cuttings than in P. alba, although P. alba showed a more rapid decrease in photosynthesis in response to nonaeration stress. Ion distributions in the leaves and roots differed between species. P. alba was superior to P. nigra in terms of Na ? exclusion capacity, such that most of the absorbed Na ? was confined to the root system, with little reaching the leaves. The distributions of K ? , Ca 2? , and Mg 2? in the leaves and roots of each species under the two stressors were also analyzed. The lower Na ? /K ? ratio in leaves indicated that P. alba was more tolerant to salt stress than P. nigra.

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摘要：中国内蒙古自治区の毛烏素沙地で緑化に利用される Salix psammophila C.Wang et Ch.Y.Yang と S. matsudana Koidz.の当年 生挿し木苗を水耕栽培によって育成し，NaCl（0，50，100 mM）による塩ストレスが成長，光合成，および葉内のベタイン蓄積に およぼす影響を比較した。その結果，両樹種とも 100mM の NaCl 処理区で成長，および光合成は強く抑制された。50mM，100mM の処理区では，両樹種とも根に Na + 蓄積が見られた。S. psammophila の葉の 100mM 処理区で Na + がわずかに増加したが， S.matsudana では顕著に増加した。 両樹種の葉におけるグリシンベタイン含有量は 100mM 処理区で， β-アラニンベタインは 50mM or 100 mM NaCl were investigated. The treatment of 100mM NaCl greatly suppressed growth and photosynthesis of both species. In both 50 and 100mM NaCl treatments, Na + accumulation occurred in roots of both species. The accumulation of Na + in leaves of 100mM NaCl treated S. matsudana cuttings was greater than that of S. psammophila cuttings. In leaves of both species, 100mMNaCl slightly increased glycine betaine content and 50mM NaCl enhanced β-alanine betaine increment. Effects of methyl jasmonate (MeJA) solution (0, 1, 5 or 10mM) sprayed to leaves on growth and physiology of the cultured cuttings also were studied. The application of MeJA solutions did not affect growth, physiology or bataine accumulation in both species.

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