Effect of nitrogen application on the phytochemical production in Jatropha curcas L. (Angiosperms: Euphorbiaceae) during drought conditions

Nitrogen is an important nutrient for the successful metabolism of plants, but its occurrence in soil is always very limited. This nutrient has a significant role to preserve plants during various stress conditions by altering the production rate of phytochemicals as defense weapons. Hence, this study was carried out to analyze the effect of nitrogen supply on the phytochemical composition and relative water content in Jatropha curcas L. under a simulated drought condition. The selected seedlings were grown from stem cuttings and categorized into different treated three groups along with the control. After the completion of the experiment, the growth pattern and phytochemical production were investigated. An increased malondialdehyde activity (MDA) was reported with a reduction in relative water content (RWC) of the leaf and in the biomass of seedlings under drought stress. A significant decrease in the levels of alkaloids, phenol, flavonoids and tannins with an increase in saponins and terpenoids was also observed in only simulated drought stressed plants. While a significant increase in the levels of total alkaloid, tannins, flavonoids and phenols was observed in those plants where exogenous nitrogen was supplied before the start of drought periods, unlike in treated and control plants. Therefore, it was revealed that application of Nitrogen enabled the plants to possess protective mechanism through the production of phytochemicals that facilitate the cell membrane to reduce the detrimental effects caused by drought stress

Crude oil induced oxidative stress in Capsicum annum L

Abstract: This study was conducted to evaluate the effects of Bonny light crude oil on the malondialdehyde (MDA) and antioxidant enzymes activity in Capsicum annum. Seedlings were grown for 5 weeks in nursery bags filled with sandy-loam soil amended with crude oil to achieve 0, 1, 3 and 5% v/w. Metabolic parameters representative of oxidative damage and antioxidant enzymes activity were evaluated after the treatments. The results showed that crude oil caused a significant decrease in the relative water content (RWC) of the plant and a significant increase in MDA level, and activities of catalase and ascorbate peroxidase. It was observed that the effects were concentration dependent. It was concluded that crude oil in soil made water absorption by plants difficult and also induced oxidative stress in plants. [Odjegba VJ, Badejo JO. Crude oil induced oxidative stress in Capsicum annum L. Nat Sci 2013;11(2):46-50]

Arrested Development in Manihot Esculenta Crantz Exposed to Nigeria\u2019s Forcados Blend Crude Oil

The susceptibility of Manihot esculenta to Nigeria\u2019s Forcados blend crude oil was investigated for 8 weeks using soil supplemented with 0-5% v/w oil/soil. Parameters considered include, plant height, leaf area, dry weight, relative growth rate, total chlorophyll and nitrate reductase activity of the plant. A significant (p=0.05) reduction in these parameters were observed in plants exposed to oil treatments. Comparatively, the control plants had a mean height and chlorophyll level of 43.27\ub13.08 cm and 3.2468\ub10.0038 mg g-1 f.wt respectively after 8 weeks, while plants grown in soil containing 5% oil correspondingly had 23.70\ub10.00 cm and 1.9374\ub10.0052 g-1 f.wt. The oil treatment also had a significant inhibitory effect on the nitrogen metabolism of the plant as indicated by nitrate reductase activity. The results of this study showed the toxic effects of Nigeria\u2019s Forcados blend crude oil on Manihot esculenta

Arrested Development in Manihot Esculenta Crantz Exposed to Nigeria’s Forcados Blend Crude Oil

The susceptibility of Manihot esculenta to Nigeria’s Forcados blend crude oil was investigated for 8 weeks using soil supplemented with 0-5% v/w oil/soil. Parameters considered include, plant height, leaf area, dry weight, relative growth rate, total chlorophyll and nitrate reductase activity of the plant. A significant (p=0.05) reduction in these parameters were observed in plants exposed to oil treatments. Comparatively, the control plants had a mean height and chlorophyll level of 43.27±3.08 cm and 3.2468±0.0038 mg g-1 f.wt respectively after 8 weeks, while plants grown in soil containing 5% oil correspondingly had 23.70±0.00 cm and 1.9374±0.0052 g-1 f.wt. The oil treatment also had a significant inhibitory effect on the nitrogen metabolism of the plant as indicated by nitrate reductase activity. The results of this study showed the toxic effects of Nigeria’s Forcados blend crude oil on Manihot esculenta

Salicylic Acid Enhances Growth, Photosynthetic Performance and Antioxidant Defense Activity Under Salt Stress in Two Mungbean [Vigna radiata (L.) R. Wilczek] Variety

Salt is regarded as a main cause for reduced yield under challenging conditions. Mungbean, a valuable protein crop, is sensitive to salt stress, leading to yield shortage. The growth hormone, salicylic acid (SA), enhances several processes necessary to confer salt tolerance and relieves poor agricultural yield. Seeds of mungbean were initially pretreated with SA (0.5 mM) for 4 h before sowing, while under a cumulative combination of SA + salt regimes: control, SA, 100 mM, SA +100 mM, 200 mM and SA +200 mM. Our study examined photosynthesis parameters such as photosynthetic pigment concentration, chlorophyll a fluorescence, protein, proline, and antioxidant enzymes in plants subjected to single and combined SA + salt stress concentrations. The result showed a greater decline in SPAD and photosynthetic quantum yield under 200 mM NaCl at 43% in Var. 145 than in Var. 155 at 32% compared to 11% in SA +100 mM and 34% in SA + 200 mM treatments in both varieties. Var. 145 was found to be more sensitive to 100 and 200 mM NaCl salt stress. In Var. 155, chlorophyll a and chlorophyll b concentrations were higher under control 52%, SA + 100 mM 49%, and SA +200 mM 42% than in Var. 145 at 51%, 38%, and 31%. Protein and proline revealed a higher content in Var. 155 in contrast to the lower activity in Var. 145. The enhanced performance of the Var. 155 exposed to SA + salt stress was followed by an increase in the activities of peroxidase (POD), CAT while the activity of MDA revealed a significant increase in Var. 145 under 100 mM 43% and 200 mM 48% NaCl treatment compared to Var. 155, which had 38% and 34%. The above results suggest that SA-treated Var. 155 confers tolerance to salt stress and is accompanied with a high osmoprotectant responses as provided by SA in Var. 155 than Var. 145. The potency of SA in providing salt tolerance capacity to plants is a future research interest to maintain sustainable yield in mungbean seedlings

Silicon ameliorates cadmium (Cd) toxicity in pearl millet by inducing antioxidant defense system

Cadmium (Cd) stress is a significant environmental pollutant that can negatively impact crop yield and growth, and is a serious global issue. However, silicon (Si) has been shown to have a potential function in alleviating the effects of several abiotic stress conditions on crops, including Cd stress. This study investigated the effectiveness of applying silicon to soil as a method for reducing cadmium toxicity in pearl millet (IP14599) seedlings. Seeds of IP14599 were treated with Si + Cd element which cumulated to a combination of 9 treatments. Different Cd concentration of (0, 200, and 300 mg/kg-1) was taken and manually mixed into a sieved soil prior to planting and Si (0, 100 and 200 mg/kg-1) was selectively introduced till after attaining 12 days of seedling emergence. The physiochemical parameters of Cd stressed plants investigated includes chlorophyll, gas exchange attributes, proline, relative water contents, malondialdehyde (MDA) content and antioxidant enzymes (superoxide dismutase (SOD),catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD). Our result revealed that the metal (Cd) caused serious oxidative impairment thereby reducing photosynthetic performance, increased activity of MDA and Cd content in the roots and leaves of IP14599.In addition, Si increased the growth pattern and antioxidant defense action thereby mitigating the Cd toxicity. The results revealed that at Si 200, Si significantly increased the chlorophyll, carotenoids and plant height at 122 %, 69 % and 128 % under the Cd 200 and Cd 300 mg/kg-1 treatment, respectively. The single treatment at Si100 and Si 200 decreased ROS by 29 %, and 37 % respectively and MDA decreased by 33 % and 43 % in contrast to Cd 200 and 300 treatments, respectively. However, Si200 showed significant increase in the activities of APX 97 %, SOD by 89 %, CAT 35 % and POD 86 % as compared to single Si, Cd or combine Cd + Si treatment. Also, a gradual decline in Cd level in both the leaf and root was present when exposed to high concentrations of Si at Si200 and 300 mg/kg-1. Our findings revealed that Si might significantly increase the capacity to tolerate Cd stress in crop plants. Therefore, the study revealed that Si has the potential to alleviate Cd-induced toxicity by reducing Cd assimilation and enhancing the growth attributes of IP14599 plants