Peanut plants based bioassay for iron deficiency and its remediation

Abstract

Chlorosis is rarely seen in natural vegetation. It occurs mainly in modern intensive agriculture, which also demands high crop yield. The search for an inexpensive and efficient way of correcting chlorosis and for alternative remedy practices such as organic composts, natural chelates, and synthetic chelates is an ongoing process. Peanut (Arachis hypogaea L.) plants grow rapidly, and develop chlorosis when grown in soils with high lime levels. An appropriate treatment can achieve their full remediation, therefore, they are suitable for testing for Fe deficiency. In the present study we tested different cultivars; different soil types; and the remediation of the plants using two levels of FeEDDHA. The remediation process is essential for a comprehensive setup of the bioassay since fully green plants serve as a “positive,” healthy plant, control. The study showed that among the cultivars tested for use in a bioassay for the remediation of Fe induced chlorosis, cv. David served best the purpose of the bioassay. When fertilizers are absent, severe chlorosis develops after 5 weeks; the chlorosis is remediable with FeEDDHA, with full recovery 10 to 12 d after treatment. Since Shulamit has been the cultivar on which the bioassays of many chelates, cultivars and soils was used and recommended by our group in the early 1980's, and in many tests conducted for chelate producers ever since, the possibility of upgrading the resolution and sensitivity of the bioassay by selecting a more suitable cultivar is greatly desired. The bioassay test suggested here can be used to screen plant cultivars for Fe efficiency (based on the soil chosen), to evaluate the effectiveness of fertilizers in the remediation of Fe deficiency, and to grade soil types as a cause for Fe deficiency in plants.