جستجوی مقالات مرتبط با کلیدواژه "onion" در نشریات گروه "زیست شناسی"

Seed development and vigor may be influenced by harvest time and height of harvest in onion seeds.Thus,an experiment was conducted to evaluate the effects of different harvest times and height of harvest in enzymatic activity and biochemical changes of seeds in two growth seasons(2014-2015) at Research Farm of the Seed and Plant Institute,Karaj,Iran.The experimental design was a factorial in a randomized complete block with three replications. Four times of harvest (T1(moisture content:60%), T2(moisture content:50%), T3(moisture content:39%), and T4(moisture content:11%)) and four harvest height (0,10,20and30cm bottom of inflorescence) were randomized to the plots. Seeds were harvested in 10 days intervals at four stages during development and maturity. The results showed in both of studied years the maximum catalase(1.847 OD/mg protein min-1) and peroxidase activity(3.852 OD/mg protein min-1) and also the minimum MDA content(0.068 nm g FW) were achieved in 3rd harvest time and 20cm height of harvest. In agreement with the achieved result about enzymatic activity, the maximum 1000seed weigh (4.440g) was observed in the second year and third harvest with 20cm height of harvest. Maximum seed vigor as measured by the electrical conductivity of seed leachate(58.70 μs/cm/g) was obtained at second harvest time with 20cm height of harvest. In this study, earlier harvests due to immaturity and later harvests because of aging reduced seed vigor of onion. The best treatment for achieving suitable seeds was third harvest time and 20cm height of harvest.Also, biochemical traits were helpful in determining the suitable time of harvesting in onion seeds.

Some natural compounds of plants including phenols and alkaloids induce mitosis depressive that are blocked cell division. Field dodder (Cuscuta campestris Yunck.) and eastern dodder (Cuscuta monogyna Vahl.) are the most widespread obligatory parasitic species. In the present study, end of summer 2015, field dodder and eastern dodder are collected from Alhagi maurorum Medik. host and Vine (Vitis sylvestris C.C.Gmel.) host respectively from Markazi province of Iran and identified by department of botany of Islamic Azad University of Saveh. The aerial parts of dodders were used for aqueous extract. Dodders alkaloid and poly phenol were visualized by TLC and Dragendorff (for alkaloid) and ferric salt (for poly phenol) reagents. Total phenols and alkaloid were measured by using the calibration and spectrophotometry methods. Root length and roots tip meristem model of onion bulbs and barley seedlings were utilized to allelopathy and antimitotic effects of dodders aqueous extracts. Standard cytotoxic 8-Hydroxyquinoline served as controls. The bulbs and barley seedlings were treated at various concentrations: 0.05, 0.1 and 0.2 mgml-1 (dw) of and aqueous extract of dodders and 8Hydroxyquinoline for 6 and 12 h. The inhibitory effect of dodders extract were evaluated on the growth and mitotic activity (Mitotic index) of barley seedlings and onion root meristems and the effect was compared with standard 8-Hydroxyquinoline. The One Way ANOVA test was used for statistical analysis. The poly phenols of field dodder was condensed tannins (include flavonoids) but for eastern dodder hydrolysable tannins. Like 8-Hydroxyquinoline, both field and eastern dodders extracts significantly inhibited the growth of roots and mitotic activity in incubation time and dose-dependent manner. However, C. campestris extract was more allelopathy and antimitotic potent in this regard and produced root decay and mitosis arrest. The extract of dodders had inhibitory and mitosis depressive effect on root tip meristem cells. In the present study we found, the dodders aqueous extracts can been used to produce desirable effects as it pertains to chromosome condensation and spread, and though the roles of these chemicals in spindle fiber inhibition have been elucidated, as 8-Hydroxyquinoline.