ABSTRACT
OBJECTIVE:To study the effects of exogenous abscisic acid(ABA)on salt-alkali tolerance of Scrophularia ning-poensis seedlings,and to provide theoretic evidence for cultivating S. ningpoensis in salt-alkali soil. METHODS:50 S. ningpoensis seedlings were divided into control group,salt-alkali group(75 mmol/L),salt-alkali(75 mmol/L)+ABA low-concentration,medi-um-concentration and high-concentration groups(10,50,100 μmol/L),with 10 plants in each group. 20 days after transplanting, the plants were sprayed with drugs every 4 days. Growth indexes of the plants(length of stem,fresh weight,dry weight,survival rate),physiological indexes [the contents of chlorophyll,soluble sugar (SS),soluble protein (SP) and free proline (Pro)],the contents of MDA and H2O2,the activities of antioxidase [the activities of SOD,POD,CAT,GR] and the contents of Na+ and K+in stem and root were determined in each group 2 weeks later. RESULTS:Compared with control group,stem height and survival rate of S. ningpoensis seedlings,SP,the contents of Na+ and K+ in the stem,the contents of Na+,CAT and GR in the roots were all decreased significantly in salt-alkali group;while chlorophyll,Pro,MDA and H2O2 contents,the content of K+ in the roots and the activities of SOD and POD were all increased significantly(P<0.05 or P<0.01). Compared with salt-alkali group,stem height of S. ningpoensis seedlings,fresh weight and chlorophyll content were increased significantly in salt-alkali+ABA medium-concentra-tion group,while MDA and the content of Na+ in the stem were decreased significantly;dry weight,the contents of SS and SP, the activities of SOD and CAT were increased significantly in salt-alkali+ABA low-concentration and medium-concentration groups, while the SS content was increased in salt-alkali+ABA high-concentration group;stem height and dry weight were decreased signifi-cantly in salt-alkali+ABA high-concentration group;Pro content of salt-alkali+ABA low-concentration and high-concentration groups were decreased significantly;H2O2,Na+ content in the roots were decreased significantly in salt-alkali+ABA low-concentra-tion,medium-concentration and high-concentration groups;while GR activity,K+ content in the stem and roots were increased sig-nificantly;POD activity were decreased significantly in salt-alkali+ABA medium-concentration and high-concentration groups. CON-CLUSIONS:The addition of a certain concentration of exogenous ABA can effectively increase salt-alkali tolerance of S. ningpoen-sis seedlings and strengthen the ability of the plant adapting to salt-alkali environment.
ABSTRACT
Aims: To investigate the effect of variations of plasma levels of thyroid and growth hormones on the physical growth indexes, the variation of these hormones with age, correlation of thyroid and growth hormones at varying concentrations of growth hormone in children aged 6-10 years. Study Designed: Department of Medical Laboratory Science, University of Calabar, conducted between March 2014 and February 2015. Methodology: Anthropometric uniqueness were described and Body Mass Index calculated for 180 (male 81 and female 99) participants of the study. Thyroid and growth hormones were determined by Enzyme-Linked Immunosorbent Assay (ELISA) specific for the various hormones, using STAT FAX 303 microtitre plate reader. Results: Nineteen percent (n=34) had GH values (≤0.6 ng/ml), lower than the expected normal, 64% (n=115) had values between (0.6-10.0ng/ml) while 17% (n=31) had values ≥10.0 ng/ml. Ninety two percent (n=166) of the children had thyroid stimulating hormone (TSH) values between 0.35-8.44 μIu/ml; 6.1% (n=11) had values >8.44 μIu/ml which are above normal while1.7% (n=3) had values <0.35 μIu/ml lower than normal. Triiodothyronine appears to increase from birth recording a peak within the first year of postnatal life, and then progressively declining to adult values while GH increases from birth attaining a peak about the age of nine then falling progressively to adult values. Children with apparent GH deficiency had significantly higher T3 and T4 levels and lower TSH, those with high GH values had correspondingly low T3 and T4 values and high TSH. The correlation coefficients of TSH and growth hormones in those with high and low GH (r=-0.05 and r=-0.130) respectively were both negative while that of TSH and GH in those with normal GH was positive (r=0.093), however, physical growth indexes are preserved across board. Conclusion: It was concluded from the study that growth failure may be due to failure of both hormones and may likely not occur when an unbroken synergy exist between thyroid and growth hormones during childhood.
ABSTRACT
OBJECTIVE:To study the resistance physiological responses of seedling of Scrophularia ningpoensis to the stress caused by saline and alkali at different concentrations. METHODS:The seedling of S. ningpoensis was placed in the illumination in-cubator,in which the temperature was maintained at(20±2)℃,light-dark cycle at 13 h/11 h and illumination intensity at 2 000 lx. The alkali (NaHCO3) of 50,100,150,200 and 250 mmol/L and the saline (NaCl) of 50,100,150,200 and 250 mmol/L were poured once every 4 days for 16 consecutive days. The growth indexes(plant height,fresh weight,dry weight),chlorophyll (Chl) content,antioxidative indexes [superoxide dismutase (SOD),catalase (CAT),peroxidase (POD),hydrogen peroxide (H2O2),malonaldehyde (MDA),membrane penetration (RMP)],and osmotic regulation physiological indexes [soluble sugar (SS),soluble protein(SP)and proline(Pro)] of the seedling were determined. There set a blank control group(distilled water). RESULTS:For saline concentration higher than 50 mmol/L and alkali concentration higher than 150 mmol/L,the seedling height, fresh weight and Chl content were lower;for saline concentration higher than 100 mmol/L and alkali concentration higher than 150 mmol/L,the dry weight of the seedling was lower. For saline concentration of 50 mmol/L and alkali concentration of 150 mmol/L, the activities of SOD and POD were the strongest;for saline concentration of 150 mmol/L and alkali concentration of 50 mmol/L, the activity of CAT was the strongest. The contents of H2O2 and MDA increased and the content of SP decreased with the increase in saline-alkali concentration. The level of RMP increased therewith,that is to say,membrane stability decreased. For saline concen-tration higher than 100 mmol/L and alkali concentration higher than 150 mmol/L,the accumulation of SS terminated;for saline and alkali concentrations higher than 100 mmol/L,the accumulation of Pro terminated,however,the content of Pro was markedly high-er in the above-said alkali concentration than in that saline concentration. CONCLUSIONS:Saline-alkali stress causes the tissues of S. ningpoensis to produce active oxygen and its cytoplasmic membrane system to be damaged. Chl,enzymatic antioxidants such as SOD,CAT and POD,and osmoprotectants such as Pro and SS can buffer saline-alkali stress to some degree. The maximum concen-trations of NaCl and NaHCO3 that seedling of S. ningpoensis can tolerate are 50 mmol/L and 150 mmol/L respectively.