摘要
通过水培试验,采用前期以根系耐性指数为指标从12个白菜[Brassica campestris L.ssp.chinensis(L.)Makino]品种中筛选的两个对Cd耐性不同的白菜品种‘上海青’(Cd敏感型)和‘杭油冬’(Cd耐性)为试材,研究硅(Si,1.5mmol·L-1)对镉(Cd,5.0mg·L-1)胁迫下白菜生长、Cd含量、光合参数、叶片叶绿体超微结构的影响。结果表明:在Cd胁迫下,‘上海青’和‘杭油冬’与各自对照相比,地上部和地下部生物量显著降低了33.8%,30.6%和33.0%,12.0%,地上部和地下部Cd含量增加了55.2%,85.7%和73.2%,42.1%;叶片光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)和叶绿素含量均下降,细胞间隙二氧化碳浓度(Ci)增加;叶片的叶绿体结构明显受到损伤,叶绿体膨胀,叶绿体的基质片层结构破坏,片层方向紊乱。施硅后与单独Cd处理相比,两品种地上部和地下部生物量显著增加了24.9%,41.1%和31.9%,43.5%;地上部Cd含量显著降低了15.1%和26.3%,而地下部Cd含量显著增加了24.7%和33.6%;叶片的光合作用能力增强,而且叶片叶绿体超微结构变得完整。说明施硅减少了Cd从地下部向地上部的运输,提高了光合作用效率。这种缓解效应在耐Cd型品种‘杭油冬’中表现的效果更加显著。
Two pakchoi[Brassica campestris L.ssp.chinensis（L.）Makino]cultivars：i.e.Hangyoudong（HYD）,a Cd-tolerant cultivar and Shanghaiqing（SHQ）,a Cd-susceptible cultivar,were selected among 12 pakchoi genotypes based on the root tolerance index,and then grown hydroponically to investigate the effects of Si on biomass,photosynthetic parameters and leaf stoma structure and chloroplast ultrastructure in two contrasting pakchoi cultivars grown under Cd stress.Theresults showed that shoot and root biomass of SHQ and HYD with Cd treatment decreased by 33.8%,30.9% and 28.2%,6.8% compared with the corresponding controls;Cd contents were 56.2,86.6 and 44.7,62.9 times as high in the Cd treatment alone as in the corresponding control treatment.Net photosynthetic rate（Pn）,stomatal conductance（Gs）,transpiration rate（Tr）and chlorophyll content of the two pakchoi cultivars tested were all decreased under Cd-stress,while intercellular CO2 concentration（Ci）was increased under Cd-stress.Microscopic observations showed that the stoma transmutated and chloroplast structure swelled observably with chloroplast granae being destroyed heavily under Cd-stress,which were all counteracted by addition of Si.Addition of Si to Cd treatment significantly increased shoot and root biomass of SHQ and HYD by 24.9%,41.8% and 32.0%,43.5%,decreased Cd contents in shoot of both cultivars by 15.1% and 26.3%,and increased Cd contents in root of both cultivars by 24.7% and 33.6%,compared with the corresponding Cd treatments alone.The results showed that addition of Si suppressed Cd uptake in shoots and root-to-shoot transport,improved the photosynthetic efficiency.However,the alleviation of Si on above-mentioned parameters was smaller in Cd-sensitive plant cultivar than in Cd-resistant plant.
出处
《园艺学报》
CAS
CSCD
北大核心
2011年第9期1675-1684,共10页
Acta Horticulturae Sinica
基金
‘十一五’国家科技支撑计划项目(2006BAD02A15)
关键词
白菜
镉
硅
光合作用
叶绿体
超微结构
pakchoi
Brassica campestris L.ssp.chinensis（L.）Makino
cadmium
silicon
photosynthesis
chloroplast
ultramicroscopic structure
