Effect of water deficit on maize seeds (Zea mays L.) during germination

M. Kolesnikov¹, T. Gerasko¹, Yu. Paschenko¹, L. Pokoptseva¹, O. Onyschenko¹ and A. Kolesnikova²*

¹Dmytro Motornyi Tavria State Agrotechnological University, Agrotechnology and Ecology Faculty, Department of crop production and horticulture, 226 Soborny Avenue, UA69006 Zaporizhzhia, Ukraine
²Charles University, Ovocný trh 560/5, CZ11636 Prague 1, Czech Republic
*Correspondence: maksym.kolesnikov@tsatu.edu.ua

Abstract:

Global climate changes cause the frequent recurrence of droughts, which reduce crop production more than any other environmental factor. This study was conducted to access the effect of water deficit on maize seeds (Zea mays L.) DKC 5143 hybrid during germination. The tasks were to assess the influence of different rank of osmotic stress on the maize lipid peroxidation (LPO), proline content, catalase and aminotransferases activities, and morphometric parameters during the early stages of maize seeds germination. The maize seeds were exposed to five levels of water availability which produced by PEG-1500 solutions (0, 20, 50, 100, 200 g L^‑1). Seeds of maize were germinated on Petri dishes for 7 days under controlled parameters. Amounts of TBARS were increased in maize sprouted seeds by 1.9 times, coleoptiles by 1.4 times, and in roots – by 1.9 times under water deficit. Proline content increased by 9.2 times in coleoptiles and by 6.0 times in 7 days maize roots while PEG-1500 (200 g L^–1) treatment. An increasing of catalase (CAT), aminotransferases (ALT, AST) activities according to osmotic potential value was also observed. A remarkable development of maize oxidative reaction was associated with a significant reduction in emergence, wet weight and length of water-stressed plants. These results assume that the maize adaptive strategy to osmotic stress during germination was found in the activation of LPO and antioxidant components. The findings provide useful help for correcting the stress state of maize using osmotically active regulators.

Key words:

The effect of cadmium and lead pollution on growth and physiological parameters of field beans (Vicia faba)

V. Alle¹*, A. Osvalde², M. Vikmane¹ and U. Kondratovics¹

¹University of Latvia, Faculty of Biology, Department of Plant Physiology, 1 Jelgavas street, LV-1004 Riga, Latvia
²University of Latvia, Institute of Biology, Laboratory of Plant Mineral Nutrition, 3 Miera street, LV-2169 Salaspils, Latvia
*Correspondence: vita.alle@lu.lv

Abstract:

Research on the impact of soil contamination on crops is important as plants directly take up heavy metals from the soil through the roots, so heavy metals can enter the food chain. The aim of this study was to investigate the impact of cadmium (Cd) and lead (Pb) pollution on growth and physiological parameters of field beans. Plants in the vegetation experiment were grown under controlled conditions. Changes in growth and physiological parameters were studied at five levels of Cd (0–25 mg L^-1) and at 6 levels of Pb in substrate: from (0–1,000 mg L^-1) at the first day of the experiment, to (0–2,000 mg L^-1) at the end of the experiment after gradual Pb additions after every sample collecting day. Methods used for analysing the plant material: the content of amino acid proline and photosynthetic pigments were determined by spectrophotometry; chlorophyll a fluorescence parameters – using continuous excitation chlorophyll fluorimeter. The fresh weight of plant above-ground parts and roots was detected. The growth and development of field beans was slightly influenced by increasing amount of Cd and Pb in substrate only at the end of the experiment. The highest Cd treatments (Cd20 and Cd25) caused 2.5 and 1.3 times increased proline concentration in bean leaves. The chlorophyll a + b content and chlorophyll a fluorescence parameter F_v/F_m changed differently throughout the experiment. In general, during the experiment, there was a tendency for the content of proline in leaves for Pb treatments to be increased compared to control. At the end of the experiment the content of proline in field bean leaves of the highest Pb treatments (Pb600 + 100 + 400 + 500, Pb800 + 100 + 400 + 500 and Pb 1,000 + 100 + 400 + 500) was 1.66, 1.44 and 1.55 times higher, respectively, than that of the control plant leaves. The negative impact of exposure to Pb on chlorophyll a + b, chlorophyll a fluorescence parameter P_Index and F_v/F_m in bean leaves was less pronounced compared to Cd. The obtained results confirm that field beans until their flowering stage can grow and develop in the presence of a large amount of Cd and Pb in substrate without significant growth inhibition and detrimental impact on physiological parameters, if optimal cultivation conditions are provided.

Key words:

heavy metals, photosynthesis parameters, proline, Vicia faba