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Hilmi M, Hamim H, Sulistyaningsih YC, Taufikurahman. 2018. Growth, histochemical and physiological responses of nonedibleoil producing plant (Reutealis trisperma) to gold mine tailings. Biodiversitas 19: 1294-1302. Reutealis trisperma (Blanco) AiryShaw is a non-edible biodiesel producing plant that is able to grow well in various unfavorable environmental conditions. The studyaimed to analyze the growth, physiological, and anatomical responses of R. trisperma to gold mine tailings. Three-month-old of R.trisperma were grown in 8 kg of polybags contained with mixed soil-compost medium treated with 0, 25, 50 and 100% of gold minetailings for 3 months. Root and shoot growth, physiological and anatomical characters, and histochemical analysis of Pb inside the rootsand leaves were examined. The root and shoot growth as well as chlorophyll a and b contents of R. trisperma grown in sole gold minetailing at 100% significantly decreased, while at the lower concentration of gold mine tailings, the decrease of the growth performanceswas not significant, or even increased shown in that of 25% of tailing treatment. The treatment of gold mine tailing at 100% alsoinduced lipid peroxidation, indicated by the significant increase in malondialdehyde (MDA) contents in the root as well as the leaves.Histochemical analysis showed that accumulation of Pb occurred both in roots as well as in leaves of R. trisperma treated with 100% oftailings. High-level tailing treatment also induced anatomical alteration in roots as well as leaves of the species. These results indicatedthat gold mine tailings induced oxidative stress in roots and leaves of R. trisperma resulted in growth inhibition.

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Iron toxicity stress causes physiological and metabolic changes in rice and other plants. To date, there is little information about the metabolite profile of rice under Fe toxicity conditions. In fact, metabolite has a contribution to the physiological condition of plants. Plant metabolomics is a study of low-molecular weight metabolites in plants under certain conditions. The objective of the research was to investigate physiological and metabolic changes in rice under Fe toxicity stress. Two-week-old seedlings of four rice varieties with various Fe toxicity tolerance levels were stressed hydroponically with 400 ppm FeSO 4. 7H 2 O for 10 d. Numerous physiological characters were observed and untargeted metabolomic analysis was carried out using gas chromatography-mass spectrophotometry (GC-MS). The results showed Fe toxicity induced physiological and metabolite variation in rice. By comparing the metabolites synthesized in Fe toxicity-stressed plants with control plants, it showed that elaidic acid, linoleic acid, and linolenic acid could be as metabolite marker candidates for rice response to Fe toxicity stress. When plants exposed to Fe toxicity stress, elaidic acid increased, whereas linoleic-and linolenic acid decreased. The alteration of fatty acid composition in the root and shoot suggests the alteration of metabolites is one of the tolerance strategies of rice to Fe toxicity stress. This finding offers an insight about the tolerance strategies of rice under Fe toxicity stress related to the maintenance process of the cell membranes during this stress. The genes underlying biosynthesis of the fatty acid could be a target of future research on responsible genes for Fe toxicity tolerance in rice.

Metal stress is among the important environmental stresses, which influences the growth and development of plants and crops in many areas in the biosphere. Root is an important gate for the absorption of water and mineral nutrition which in many types of lands is also accompanied by a higher concentration of metal elements, either essential (such as Fe, Mn, and Cu) or non-essential metal elements or heavy metals (such as Al, Pb, Hg, Cd, and Ag). In response to metal stress, plant roots sometimes develop a cellular structure to prevent excessive concentration of metal components to avoid toxic effects and cellular damage. Physiological and biochemical responses at the cellular level, which result in ultrastructure changes may occur due to or to avoid the negative effect of metal toxicity. In many cases it was followed by the reduction of root growth followed by discontinuing entirely plant growth. On the other hand, the structural changes are an important part of root mechanism to sustain the plant from metal toxicity. In this chapter, different changes in the cellular ultrastructure resulting from toxic damage or indicating tolerance response to metal stress will be elucidated.