摘要
[目的]探讨不同pH和镉(Cd)浓度对雪茄烟种子萌发和幼苗生长生理的影响,以期为优质、安全的雪茄烟原料生产提供参考.[方法]采用水培试验,设不同pH(3、5、7、9和11)和不同Cd浓度(0、10、50和250 µmol/L)处理;测定不同处理的种子萌发指标(发芽率和发芽势)、幼苗生长生理指标[胚根长、胚芽长、干物质重、叶绿素含量、硝酸还原酶活力、丙二醛(MDA)含量、根系活力]和幼苗各部位Cd含量.[结果]Cd浓度相同时,随着pH增加,雪茄烟种子的发芽率呈先升高后降低的变化趋势;相同pH条件下,添加Cd处理的雪茄烟种子发芽率随着Cd浓度的增加呈降低趋势;pH为7、Cd浓度为10 µmol/L时,种子发芽势和发芽率最高.在相同pH条件下,雪茄烟幼苗胚根长随着Cd浓度的升高呈先增加后减小的变化趋势;pH为3和7时,幼苗胚芽长随着Cd浓度的升高逐渐减小,其他pH条件下幼苗胚芽长随着Cd浓度的升高先增加后减小;pH为9、Cd浓度为10 µmol/L时,胚根长和胚芽长达最大值.除0 µmol/L Cd处理外,雪茄烟幼苗的干物质重随着Cd浓度的升高而降低,随着pH的升高而先升高后降低.10～250 µmol/L Cd处理下,雪茄烟幼苗根部、茎秆和叶片的Cd含量大多随着pH的升高逐渐降低,随着Cd浓度的增加而增加.烟草幼苗的叶绿素含量、硝酸还原酶活力、根系活力随着pH的升高呈先升高后降低的变化趋势,但随着添加Cd浓度的升高而降低.pH在5～11时,雪茄烟幼苗中MDA含量随着Cd浓度的增加而增加,10～250 µmol/L Cd处理下,MDA含量随着pH升高呈升高—降低—升高的变化趋势,均在pH为7时达最小值.[结论]低浓度的Cd对雪茄烟种子萌发有促进作用,随着Cd浓度升高,雪茄烟幼苗生长生理受到抑制.pH变化会影响雪茄烟幼苗对重金属Cd的吸收积累,进而影响雪茄烟幼苗的正常生长和干物质积累,当pH为7时,10µmol/L Cd处理提高了雪茄烟幼苗的叶绿素含量、硝酸还原酶活力和根系活力,有利于幼苗生长.
Abstract
[Objective]This paper explored the effect of different pH and cadmium(Cd)concentrations on physiology of seed germination and seedling growth of cigar,in order to provide reference for obtaining high-quality and safe cigar raw material.[Method]Hydroponics experiment was carried out and different pH(3,5,7,9 and 11)and Cd concentra-tions(0,10,50 and 250µmol/L)were set.The seed germination indexes(germination rate and germination energy),seedling growth physiological indexes[radicle length,embryo length,dry matter weight,chlorophyll content,nitrate re-ductase activity,malondialdehyde(MDA)content,root activity]and Cd content in various parts of seedlings were mea-sured.[Result]Under the same Cd concentration,the germination rate of cigar seeds first increased and then decreased with the increase of pH.Under the same pH,the germination rate of cigar seeds treated with Cd decreased gradually with the increase of Cd concentration.The germination energy and germination rate of seeds were the highest when pH was 7 and the Cd concentration was 10µmol/L.Under the same pH,the radicle length of cigar seedlings first increased and then decreased with the increase of Cd concentration.The embryo length of seedlings decreased with the increase of Cd concen-tration when pH was 3 and 7.Under other pH conditions,the embryo length of seedlings increased at first and then de-creased with the increase of Cd concentration.The radicle length and embryo length reached the longest when pH was 9 and Cd concentration was 10 umol/L.Except for the treatment of 0µmol/L Cd,the dry matter weight of cigar seedlings decreased with the increase of Cd concentration,and increased at first and then decreased with the increase of pH.Under the treatment of 10-250µmol/L Cd,the Cd content in roots,stems and leaves of cigar seedlings decreased gradually with the increase of pH,and increased with the increase of Cd concentration.The chlorophyll content,nitrate reductase activi-ty and root activity of cigar seedlings increased at first and then decreased with the increase of pH,but it decreased with the increase of Cd concentration.The content of MDA in cigar seedlings increased with the increase of Cd concentration when pH was 5-11.Under the treatment of 10-250µmol/L Cd,the content of MDA increased at first,then decreased and then increased with the increase of pH,and reached the minimum when pH was 7.[Conclusion]Low Cd concentration promotes the germination of cigar seeds,but the growth physiology of cigar seedlings is inhibited with the increase of Cd concentration.The change of pH will affect the absorption and accumulation of heavy metal Cd by cigar seedlings,and then affect the normal growth and dry matter accumulation of cigar seedlings.When pH is 7,10µmol/L Cd treatment in-creases the chlorophyll content,nitrate reductase activity and root activity of cigar seedlings,being beneficial to the growth of cigar seedlings.
基金项目
河南省科技攻关项目(232102230107)
中国烟草总公司科技重大专项(110202101013XJ-05)
国家科技期刊平台
NSTL
维普
万方数据