CAJ | 학술논문

叶片早衰直接影响作物的产量与品质,因此,研究叶片早衰的分子与生理机制对于作物遗传改良具有重要的意义。本研究利用60Co-?辐射诱变水稻品种93-11获得突变体osled,其从分蘖期叶片就开始早衰,最先表现为叶尖和叶边缘变褐,并伴有红褐色斑点。在苗期经模拟干旱胁迫处理后,突变体不仅早衰,而且植株变矮以及根系变短。生理分析表明,野生型剑叶、倒二叶和倒三叶的丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性及过氧化物酶(POD)活性基本不变,但突变体则显著升高且倒二叶和倒三叶极显著高于野生型；突变体和野生型三片叶的可溶性蛋白含量、过氧化氢酶(CAT)活性及叶绿素总含量均表现下降,但突变体倒二叶和倒三叶的含量或活性均显著低于野生型。叶片经台盼蓝、二氨基联苯胺(DAB)及四唑硝基蓝(NBT)等细胞组织化学染色及透射电镜分析表明, osled叶片细胞膜系统已破坏, H2O2和O2?积累,叶绿体已开始解体。遗传分析表明, osled受1对隐性基因控制,借助图位克隆技术将该基因定位于第3染色体长臂的RM15528与RM15553两个标记之间,遗传距离均为0.7 cM,该结果为进一步克隆OsLED基因并研究其功能奠定了基础。
협편조쇠직접영향작물적산량여품질,인차,연구협편조쇠적분자여생리궤제대우작물유전개량구유중요적의의。본연구이용60Co-?복사유변수도품충93-11획득돌변체osled,기종분얼기협편취개시조쇠,최선표현위협첨화협변연변갈,병반유홍갈색반점。재묘기경모의간한협박처리후,돌변체불부조쇠,이차식주변왜이급근계변단。생리분석표명,야생형검협、도이협화도삼협적병이철(MDA)함량、초양화물기화매(SOD)활성급과양화물매(POD)활성기본불변,단돌변체칙현저승고차도이협화도삼협겁현저고우야생형；돌변체화야생형삼편협적가용성단백함량、과양화경매(CAT)활성급협록소총함량균표현하강,단돌변체도이협화도삼협적함량혹활성균현저저우야생형。협편경태반람、이안기련분알(DAB)급사서초기람(NBT)등세포조직화학염색급투사전경분석표명, osled협편세포막계통이파배, H2O2화O2?적루,협록체이개시해체。유전분석표명, osled수1대은성기인공제,차조도위극륭기술장해기인정위우제3염색체장비적RM15528여RM15553량개표기지간,유전거리균위0.7 cM,해결과위진일보극륭OsLED기인병연구기공능전정료기출。
Leaf early senescence directly affects crop yield and quality, therefore, it is of great importance to study its molecular and physiological mechanisms. In this study, we obtained a leaf early senescence mutant, osled, by irradiating rice variety 93-11 with 60Co-γray. The mutant showed early senescence symptoms, such as grey leaf tip and edge and red-brown lesions on leaf, even at tillering stage. Under the condition of simulated drought stress, seedlings of the mutant appeared in obviously shortened plant height and root length. Besides, physiological and biochemical indices in the mutant varied significantly. Under drought stress, the wild type maintained stable levels of malondialdehyde (MDA) content and activities of superoxide dismutase (SOD) and peroxidase (POD) in the top three leaves; however, the mutant showed significantly increased MDA content and SOD and POD activities in these leaves. Although the contents of soluble protein and chlorophyll and catalase (CAT) activity in the top three leaves decreased in both wild type and the mutant, the reductions in the second-top and third-top leaves of the mutant were significantly greater compared to those of the wild type. The results of histochemical staining by trypan blue, 3,3’-diaminobenzidine (DAB), and nitro blue tetrazolium (NBT) disclosed the destruction of membrane system and the accumula-tion of H2O2 and O2?in the mutant. Besides, ultrastructure of mesophyll cells further explained the degradation of chloroplast in the mutant. A single recessive gene was found to control the senescence trait according to genetic analysis, and the OsLED gene was mapped in the marker interval RM15528–RM15553 on the long arm of chromosome 3, with bilateral genetic distance of 0.7 cM.