菊花缺镁症的营养诊断研究

以镁不同浓度砂诱导菊花缺镁的典型症状，研究缺镁后植株体内矿质成分及生理生化特性的变化，提出营养诊断方法。结果表明，初花期是进行诊断的可靠时期，叶片能良好地反映供镁状况，此时，菊花叶片镁素营养的监界范围是０．２０４％～０．２１５％，缺镁的监界值为０．１９％，叶片钾镁比值低于３２为正常，过氧氢酶活性可作为诊断的辅助指标。菊花无土栽培时，营养液中镁浓度至少应在１４ｍｇ／１以上才不致发发生缺镁症。

Studies on Diagnosis of Magnesium Deficiency in Chrysanthemum

The experiment was conducted to investigate the changes in mineral cotents and physiological and biochemical characteristics in leaves of chrysanthemum ( Dendranthema grandi flora Tzvel. ) grown in grass- sand pots irrigated with nutrient solution of different Mg concentrations, with a view to proposing some practical methods for diagnosing Mg-deficiency in chrysanthemum. The visual symptoms were distinct when the plants were suffering. Mg-deficiency, The early flowering period was suitable for diagnosis. Mg concentration in leaf tissue could effectively indicate the availability of Mg from the media. There was a minimum critical foliar level of Mg concentration that must be lower than 0.19% of leaf dry weight before the symptoms appeared, but when it was about 0.204%~0.215% or K / Mg ratio was below 32, no symptoms would occur. Catalase activity could be reasonably used as a supplementary indicator of Mg status. 14mg/ 1 Mg in nutrient solution was sufficient to prevent plants from Mg-deficiency.