摘要:
通过水培试验,研究了不同水平外源氯处理对向日葵(Helianthus.annuus)幼苗生长、干物质积累、Cl-、NO3-、全N、全P、全K含量的影响。结果表明,不同浓度外源氯(Cl-6.253～00.mmol/L)处理8.d,油葵幼苗的茎生长速率均显著下降,外源Cl-浓度越大,生长下降越显著。Cl-6.252～5.mmol/L处理8.d,油葵幼苗干物质积累速率极显著高于对照,Cl-25、50.mmol/L处理,油葵幼苗的干物质积累速率与对照差异不显著;而Cl-2003～00.mmol/L处理的幼苗干物质积累极显著下降。Cl-处理下,植株体内氯含量极显著上升,而叶片中硝酸盐含量显著下降,其中以Cl-50.mmol/L处理的叶片硝酸盐含量最低。Cl-6.251～00.mmol/L处理,油葵幼苗茎、叶全N、全P含量与对照差异不显著;Cl-200.mmol/L处理下,叶、茎全N含量显著下降,而根系全N、全P含量随Cl-处理的增加而增加。随着Cl-浓度处理的提高,油葵幼苗根、茎、叶的全K含量增加,其中以根、茎增加较快。因此,一定范围的外源氯处理,不影响向日葵生物量甚至促进生物量积累的同时,也可明显的提高向日葵幼苗的氮素利用效率。
关键词:
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向日葵 /
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氯 /
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生物量 /
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硝酸盐 /
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养分
Abstract:
The chloride(Cl) ion is present in abundance almost everywhere in the world.It is required as a micronutrient for optimal plant growth.The influence of the chloride ion on plant growth depends on the plant variety.The dependence of modern agriculture on irrigation and chemical fertilization causes more concern about chloride toxicity than deficiency.The impact of Cl ion might help to increase N use efficiency in many crop plants.However,the studies mentioned above provided little information on sunflower(Helianthus annuus).There are great differences in tolerance to chloride salts among crops.So far,studies on chloride tolerance of sunflower have been very limited.Seedling growth rate,dry matter accumulation rate per plant,Cl-,NO3-,N,P and K content in sunflower seedlings under different chloride concentration treatments were studied in hydroponic experiment.The results showed that stem growth rate decreased significantly under Cl-6.25-25 mmol/L for 8 d,the higher the concentration of Cl-,the greater the decrease of plant growth.Dry matter accumulation rate of Cl-6.25-25 mmol/L treated seedlings were more than that of control,while no significant difference was found among dry matter accumulation rate of Cl-25,50 mmol/L treated seedlings and control seedlings.Dry matter accumulation of Cl-200300 mmol/L treated seedlings was obviously less than that of control.Chloride content in plant was significantly increased,while nitrate content decreased under chloride treatments.Nitrate content of Cl-50 mmol/L treated seedlings was the lowest among those treatments.N,P content of stem and leaf in Cl-6.25-100 mmol/L treated seedlings did not differ significantly from control.N content of stem and leaf in Cl-200 mmol/L treated seedlings decreased obviously,while the N and P content in root increased with supplemental Cl-concentration.K content in root,stem and leaf of seedlings gradually increased with supplemental Cl-concentration.Thus,nitrogen utilization efficiency of sunflower seedlings was increased while biomass accumulation of plant was not affected or increased under supplemental Cl-treatments(Cl-6.25-50 mmol/L).However,growth of sunflower seedlings was inhibited when being exposed to high level supplemental Cl-(Cl->100 mmol/L) due to reduced nutrient absorption.
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