1,2,4-三氯苯胁迫对水稻分蘖盛期植株生长和生理特性的影响

在土培条件下，以对1,2,4-三氯苯(TCB)敏感性显著差异的宁粳1号(敏感)和扬辐粳8号(耐性)为对象，研究了不同浓度1,2,4-三氯苯(TCB)胁迫对两种水稻分蘖盛期生长和生理特性的影响。结果表明，不同浓度TCB胁迫下，敏感基因型宁粳1号最长根长、株高、单穴分蘖数、地上部和地下部干物重随胁迫程度加深均显著递减; 耐性基因型扬辐粳8号在低浓度(20 mg kg^-1) TCB胁迫下，最长根长、地上部和地下部干物重极显著增加，当中高浓度(40 mg kg^-1、60 mg kg^-1) TCB胁迫时，最长根长、株高、单穴分蘖数、地上部和地下部干物重显著下降。不同浓度TCB胁迫下，敏感基因型宁粳1号根系活力、叶绿素含量、叶片和根系可溶性蛋白质含量相对较低，叶片和根系超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性明显降低，O₂^?产生速率和丙二醛(MDA)含量显著增高; 耐性基因型扬辐粳8号在低浓度(20 mg kg^-1) TCB胁迫下，根系活力、叶片和根系的可溶性蛋白含量、SOD、POD、CAT活性极显著增加，O₂^?产生速率和MDA含量极显著降低，当中等浓度(40 mg kg^-1) TCB胁迫时，SOD、POD、CAT活性虽然增强，但O₂^?产生速率显著增加，MDA大量积累，当高浓度(60 mg kg^-1) TCB胁迫时，其根系活力、叶绿素含量极显著降低，根系中SOD、CAT活性显著降低，O₂^?产生速率和MDA含量显著增加。总之，低浓度TCB胁迫下，长势良好、叶片和根系可溶性蛋白质含量高、抗氧化系统清除活性氧能力强、膜脂过氧化程度低是耐性基因型扬辐粳8号区别于敏感型宁粳1号的主要特征。

Effects of 1,2,4-trichlorobenzene on Growth and Physiological Characteristics of Rice at Top Tillering Stage

A soil culture experiment was conducted to study the effects of 1,2,4-trichlorobenzene (TCB) on morphological and physiological indexes of rice at top tillering stage, using rice cultivars of Ningjing 1 (TCB sensitive genotype) and Yangfujing 8 (TCB tolerant genotype), with four treatments of TCB concentrations including 0 (CK), 20, 40 and 60 mg kg^-1. The results indicated that the maximum root length, plant height, tillers per hill, shoot and root dry weight of Ningjing 1 were all decreased significantly (P<0.05) under different concentrations of TCB. Low TCB stress (20 mg kg^-1) significantly increased Yangfujing 8’s maximum root length, shoot and root dry weight , root activity (P<0.01), while medium and high TCB stresses (40 and 60 mg kg^-1) decreased maximum root length, plant height, tillers per hill, shoot and root dry weight significantly(P<0.05). Ningjing 1’s root activity, chlorophyll content, soluble protein content in leaves and roots were relatively low under different concentrations of TCB, at the same time, its activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in leaves and roots decreased, while O₂^? producing velocity and malnodialdehyde (MDA) content increased significantly (P<0.05). Low TCB stress (20 mg kg^-1) significantly increased Yangfujing 8’s soluble protein content and activities of SOD, POD, CAT in leaves and roots, and significantly (P<0.05) decreased its O₂^? producing velocity and MDA content. Under medium TCB stress (40 mg kg^-1), the activities of SOD, POD, CAT in leaves and roots were enhanced, however, its O₂^? producing velocity and MDA content increased significantly. High TCB stress (60 mg kg^-1) decreased its root activity, chlorophyll content, the activities of SOD, POD, CAT in leaves and roots, and increased O₂^? producing velocity and MDA content significantly (P<0.05). In a word, compared with sensitive genotype, well growth vigor, high protein content in leaves and roots, better ability of antioxidant system in scavenging reactive oxygen speciesand lower membrane lipid peroxidation under low concentration TCB stress (20 mg kg^-1) are regarded as the main features of TCB tolerant genotype in rice.