作 者 ：汪洪;周卫;林葆
期 刊 ：植物营养与肥料学报 2001年 7卷 1期 页码：78-87
Keywords:calcium, cadmium, maize, physiological characteristics,
摘 要 ：采用溶液培养试验 ,研究不同的钙和镉处理对玉米植株生长、叶绿素含量、硝酸还原酶和ATPase酶活性以及叶片中丙二醛含量、活性氧清除酶系统活性的影响。结果表明 ,根部未供钙或叶面喷施CaCl2时 ,加镉处理玉米根、地上部生物量降低 ,根冠比加大 ;而根部供钙 ,植株生长较好 ,生物量较高 ,根冠比相对较小。营养液中加镉 ,玉米植株中镉浓度显著增加 ,根部镉浓度明显比地上部高 ,根中镉约占 65%～ 78% ,地上部镉占到 22%～35%左右。根部供钙比未供钙处理 ,根中镉含量虽没有显著性差别 ,但地上部镉浓度明显较低。叶片喷施CaCl2 4次比喷施 2次处理 ,地上部镉浓度增加。供钙明显增加了玉米植株中钙浓度。未供钙的玉米叶片叶绿素含量下降 ,但叶绿素a/叶绿素b比基本不变 ;加镉处理 ,玉米叶片叶绿素a、叶绿素b及叶绿素总量下降更甚 ,叶绿素a/叶绿素b比升高 ;叶面喷施CaCl2 ,叶绿素含量也较低。前期和后期根部供钙处理 ,叶绿素下降程度有所缓解。而根部一直供钙 ,玉米叶片中叶绿素a、叶绿素b和叶绿素总量明显提高。镉抑制了玉米植株叶片硝酸还原酶活性、ATPase活性 ;根中ATPase活性以及活性氧清除酶系统超氧化物歧化酶 (SOD)、愈创木酚过氧化物酶 (Gua POD)、抗坏血酸过氧化物酶 (AsA POD)、过氧化氢酶 (CAT)受镉的诱导而增加，叶片中丙二醛(MDA)含量升高。与未供应钙加镉处理相比，根部供钙加镉处理的玉米叶片硝酸还原酶活性、ATPase活性显著增加，也明显减轻了镉对根中ATPase活性、叶片中丙二醛含量、活性氧清除酶系统SOD，POD，CAT 活性的诱导效应。间隔供钙，在一定程度上缓解了镉的毒害，但是叶片喷施CaCl2，对减轻镉毒害无明显效果。因此在本试验条件下，根部供钙对缓解玉米镉毒害有重要作用。关键词：钙；镉；玉米；生理特性
Abstract:Nutrient solution culture experiment was conducted to study effect of Ca on plant growth, chlorophyll , malondialdehyde concentration and activities of nitrate reductase, ATPase , superoxide dismutase (SOD), ascorbate peroxidase (AsA POD), guaiacol peroxidase and catalase (CAT) in maize (Zea mays L.) under Cd stress The results showed that: (1) Plants under Cd stress showed wilt, chlorosis, necrosis in leaves and black in roots; biomass of shoots and roots without Ca supply combining Cd stress strongly decreased The addition of Ca to solution could increase the biomass of plants and alleviated the Cd toxicity Plants with foliar application CaCl2 still had the symptom of Cd toxicity and low biomass weight (2) With the addition of Cd to solution, Cd concentration in roots and shoots of maize increased significantly and Cd concentration in roots were more than shoots Ca depressed the translocation of Cd from roots to tops of maize, but had no apparent effect on the absorption of Cd by roots because the concentration of Cd in roots of maize had little difference between the treatment without Ca supply combined Cd and the treatment with Ca supply combined with Cd Whereas Cd concentration in shoots with Ca supply were higher than those without Ca supply Foliar application CaCl 2 four times could increased Cd concentration in shoots compared with foliar application CaCl 2 two times (3) The contents of chlorophyll a , chlorophyll b and total chlorophyll in leaves of maize without Ca supply decreased Cd addition also markedly decreased the chlorophyll pigments and increased Chl a/Chl b ratio Chlorophyll content in leaves were significantly enhanced by Ca supply to roots in solution containing Cd Foliar application CaCl 2 couldn‘t prevent effect of Cd on chlorophyll in leaves Stopping Ca supply and adding Cd to solution or stopping Cd supply and adding Ca to solution partly reduced effect of Cd on chlorophyll in leaves (4)The activities of nitrate reductase in leaves and ATPase in roots of maize were inhibited by the treatments without Ca or with Cd supply, especially in those leaves under combination stress without Ca and Cd supply Whereas the activities of nitrate reductase in leaves and ATPase in roots of maize under Cd stress were enhanced by Ca supply (5) In those leaves and roots of maize without Ca supply, the activities of ATPase and endogenous oxygen radicals scavenging enzymes systems including SOD, AsA POD, guaiacol POD and CAT were higher than those of plants with such treatments as Ca supply continuously, stopping Ca supply adding Cd ,stopping Cd addition and resupply Ca concentration of malondialdehyde in leaves also remain pronounced levels Foliar application CaCl2 couldn‘t weakened the effect of Cd on endogenous oxygen radicals scavenging enzymes systems and malondialdehyde in plants, however increased the activities of ATPase in leaves In conclusion, Ca supply in root could alleviated Cd toxicity on growth, chlorophyll content and the effects of Cd on the activities of nitrite reductase , ATPase and endogenous oxygen radicals scavenging enzymes systems such as SOD, AsA POD, guaiacol POD and CAT in maize
全 文 ：