Effects of cold stratification on germination rate and percentage of caper (Capparis ovata Desf.) seeds

Caper is an important plant because of its high adaptability to marginal agriculture fields that are not suitable for agricultural crops. Different parts of caper such as roots, fruits, flowers and buds can be used to increase the inhabitant's income. The goal of this research is to determine germination rate and percentage of caper according to different duration of cold stratification (10, 20, 30, 40, 50 and 60 days) treatments. Cold stratification procedures under greenhouse condition were applied for eliminating seed dormancy to find the most suitable germination conditions because the presence of seed dormancy causes difficulties in seedling production. The seed germination started and stopped 21 and 57 days after sowing, respectively. While the highest germination percentage (46.6%) was obtained in seeds that were cold stratified for 60 days, the lowest germination percentage (3.6 7%) was determined in control seeds.     

Seed germination of three provenances of Pinus brutia (Ten.) as influenced by stratification, temperature and water stress

Seeds from three provenances of Pinus brutia were stratified for 0 or 45 d (days) at 4 +/- 1 degrees C and then germinated at 15 degrees C or 20 degrees C on filter paper saturated with polyethylene glycol solutions to provide water potentials of 0, -0.2 and -0.4 MPa (mega Pascal). Regardless of stratification, germination was lower at 15 degrees C than 20 degrees C for seeds of all provenances. Stratification significantly increased germination percentage at all water potentials regardless of the germination temperatures. Lowering the water potential to -0.4 MPa reduced germination for all three provenances in unstratified and stratified seeds when averaged for two temperatures, but reaction to the increased water stress was different among the provenances. Combined over two temperatures, stratified or unstratified seeds from the highest elevation (Cehennemdere) had the lowest germination performance at all water potentials, and stratified and nonstratified seeds from a coastal elevation (Silifke) had the highest germination parameters at the lowest water potential (-0.4 MPa). It might be concluded that seed germination and resistance to water stress vary according to provenance and stratification.     

部分菊科入侵种种子(瘦果)的萌发能力和幼苗建群特性

对入侵种种子生物学各方面的了解有助于更好地预测入侵趋势和评估可持续管理的策略.研究通过对部分菊科入侵种种子(瘦果)进行的室内萌发实验和土壤埋藏实验,通过与相关研究的对比和分析,对这些入侵种的萌发能力和幼苗建群特性进行了研究.10个入侵种种子室内萌发实验的结果表明,在25℃、12h光照的情况下,除钻形紫菀和一年蓬以外,被研究的其它8个种的终萌发率超过了50%,而且都显示出早期快速萌发的特点.用SPSS的曲线拟合工具对10个种的累积萌发趋势进行了曲线回归分析,对应的最佳模型均为三次曲线方程.不同土壤埋藏深度下幼苗出苗实验的结果表明,菊科8个入侵种的种子在表土的出苗率均最高,随着覆土厚度的增加,种子的出苗率逐渐降低,当覆土厚度超过3 cm以上时,所有种子均不能出苗.种子在不同的埋藏深度的出苗情况与种子的大小有关,较大种子破土能力相对较强;种子在不同的埋藏深度的出苗情况与种子本身的萌发能力也相关.土壤埋藏期限的实验结果表明,随埋藏时期的增加,小蓬草、苏门白酒草和一年蓬3个人侵种种子的活力逐步降低,在土壤中埋藏12个月后,其活力分别为21.34%、18.15%和27.38%.这些入侵种较广的种子萌发温度适应范围和高萌发率为防除工作带来了困难.在生产上,可通过不同时期的翻耕、将种子深埋等措施减少这些入侵种的危害.     

Effects of potassium humate solution and soaking periods on germination characteristics of undelinted cotton seeds (Gossypium hirsutum L.)

The present study was conducted to determine the effects of soaking in potassium humate (PH) solution (55% humic acid, 30% fulvic acid and 8% potassium hydroxide) and distilled water (DW) for different periods (0, 4, 8 and 16 hours) on germination characteristics of undelinted seeds of cotton cv Ersan-92. Radicle, hypocotyl and seedling length, radicle and hypocotyl elongation rate and vigor index increased by PH solution treatment and increasing soaking periods. The medium x soaking period interactions were significant except for germination percentage. Sixteen hour soaking period gave the highest values of investigated characteristics. It is suggested that pre-sowing PH solution treatment may be useful to provide a good stand establishment.     

Effects of different pretreatments on germination of Prunus serotina seed sources

Establishing intensive plantations of fast growing hardwood tree species that have high market values in the forest industry can narrow the gap between Turkey's demand and the supply of quality hardwood products. Black cherry (P. serotina Ehrh.) is a fast growing hardwood species with a high market value. Introducing and intensively growing black cherry (BC) in Turkey may significantly reduce the country's quality wood shortage. Adequate seed germination constitutes the first essential step for successful establishments. In this paper effects of different pretreatments, including artificial and natural stratification, on the seeds of different BC seed sources (SSs) were studied. Pretreatments had substantial effects on the dormancy breaking and germination behaviours of the SSs. Consecutive periods of complex warm and cold artificial stratification regimes longer than 90 days or natural stratification (where seeds were assumed to be naturally exposed to this complexity) resulted in best dormancy breaking and, in turn, germination among all pretreatments. Deeper dormancy and reduced germination rates of some BC seeds as the altitude of the source increases might suggest an ecological adaptive strategy of the species. BC may have deeper morphophysiological dormancy than is commonly believed. Seed size may have a positive effect on seed germination.     

Influence of pretreatment and desiccation on the germination of Laurus nobilis L. seeds

The effects of moist stratification, gibberellic acid (GA3) in combination with cold-moist stratification and desiccation on the germination of bay laurel (Laurus nobilis L.) seeds were studied. It was found that the external fleshy pericarp caused dormancy. There was also embryo dormancy and it was broken in seeds lacking pericarp either warm-moist stratification (20 degrees C day/4 degrees C night) or cold-moist stratification (4 degrees C) for 8 and 10 weeks, respectively. Gibberellic acid had little effect on germination percent and germination value of seeds without pericarp when used alone but significantly increased overall germination performance when used with cold-moist stratification. The viability of seeds dropped when the moisture content of the seeds was reduced by desiccation, and the time required to reach the critical moisture levels in the seeds differed in the different desiccation temperatures. The critical minimum seed moisture content for bay laurel was around 15% and the seeds showed the typical behavior of recalcitrant seeds.     

Protective role of Ginkgo biloba on petroleum wastewater-induced toxicity in Vicia faba L. (Fabaceae) root tip cells

The Melet is one of Turkey's economically important rivers. Most of the petroleum plants are located at fairly nearby of the river This situation is considered as main source of heavy metal pollution in the river. The present study was designed to evaluate the protective role of Ginkgo biloba (GB) on cytotoxicity induced by petroleum wastewater in Vicia faba root tip cells. For this aim, we used the germination percentage, root length, weight gain and micronucleus (MN) frequency as indicators of cytotoxicity. Additionally to the cytological analysis, lipid peroxidation analyses were also performed in V. faba roots. Heavy metal concentrations in wastewater were measured by atomic absorption spectrophotometer (AAS). The V. faba seeds were divided into six groups. They were treated with petroleum wastewater and 10, 20 and 30 microM doses of GB. As a result, the mean concentrations of heavy metals in wastewater were observed in the order: Pb > A > Ni > Cr > Fe > Cu > Zn > Cd. The highest germination percentage was observed in the seeds of the control and positive control groups (in proportion as 98 and 96%, respectively). Wastewater treatment caused a significant decrease in the germination percentage of Group III (in proportion as 44%). The highest root length and weight gain were observed in the seeds of the control and positive control groups at the end of the experimental period. The least root length and weight gain were observed in the seeds of Group III treated with wastewater alone. In the control group, the final weights of all the seeds increased about 4.08 g according to initial weight. The root lengths of the control seeds were measured as 6.80 cm at the end of the experimental period. The final weights of the seeds exposed to wastewater alone increased about 0.90 g according to initial weight. Besides, there was a significantly increase in the MDA levels of the roots exposed to wastewater. Heavy metals in wastewater significantly affected the MDA production indicating lipid peroxidation. But, GB-treatment caused amelioration in indices of the germination percentage, root length, weight gain, MN frequency and lipid peroxidation when compared with group III. Each dose of GB provided protection against wastewater toxicity and its strongest protective effect observed at dose of 30 microM. In vivo results showed that GB is a potential protector against toxicity induced by petroleum wastewater and its protective role is dose-dependent.     

Studies on seed germination and growth in weed species of rice field under salinity stress

An investigation was made to see the salt tolerance of 10 weed species of rice. Properly dried and treated seeds of weed species were placed on 9 cm diameter petridishes lined with Whatman No. 1 filter paper under 6 salinity regimes, viz. 0 (control), 4, 8, 16, 24 and 32 dS m(-1). The petri dishes were then kept in germinator at 25 +/- 1.0 degrees C and 12 hr light. The number of germinated seeds were recorded daily. The final germination percentage, germination index (GI), seedling vigour index, mean germination time and time for 50% germination were estimated. Root and shoot lengths of the weed seedlings were measured at 20 days after salt application and relative growth values were calculated. Results revealed that salinity decreased final germination percentage, seed of germination as measured by GI, and shoot and root length in all the species. Germination of most of the weed seeds was completely arrested (0) at 32 dS m(-1) salinity except in E. colona (12%) and C. iria (13.9%). The species C. iria, E. colona, J. linifolia and E. crusgalli showed better germination (above 30%) upto 24 dS m(-1) salinity level and were regarded as salt-tolerant weed species. J. linifolia, F. miliacea, L. chinensis and O. sativa L. (weedy rice) were graded as moderately tolerant and S. zeylanica, S. grosus and C. difformis were regarded as least tolerant weed species.     

盐胁迫下外源硅对硅突变体与野生型水稻种子萌发的影响(Effects of Silicon on the Germination of Si Mutant Rice and Wild Rice Seeds under Salt Stress)

为深入了解盐胁迫下外源硅(Si)对水稻种子萌发的作用,采用溶液培养法研究了外源Si对盐胁迫下野生型和硅突变体水稻(不能正常吸收Si)种子萌发各指标的影响.结果表明,随着NaCl浓度的提高(0～150mmol·L-1),两种水稻的芽长、发芽势、发芽率均不断降低.在150mmol·L-1NaCl胁迫下,野生型和硅突变体水稻的芽长分别为0.33cm和0.55cm,仅为对照的8.0%和11.1%;发芽率仅为对照的29.7%和53.7%;发芽势则分别降低至0%和2%.外源Si可以提高盐胁迫下两种水稻的发芽指标,且对硅突变体水稻的影响显著大于野生型水稻.2mmol·L-1Si浸种+2mmol·L-1Si处理可使野生型水稻芽长、芽重和发芽率分别比对照增加127.27%、169.23%和55.17%,发芽势则由对照时的0%提高至23.33%;硅突变体水稻芽长、芽重和发芽率分别比对照增加307.27%、285.71%和80.29%,发芽势则由对照时的2%提高至82.22%.     

六六六(HCHs)在小白洋淀水生植物中的分布与富集

利用GC-ECD测定了小白洋淀6个采样点的9种浮水、挺水和沉水植物中4种六六六(hexachlorocyclohexanes,HCHs)异构体的含量,分析了其分布、组成及富集特征。结果表明:1)小白洋淀水生植物中总HCHs含量范围在ND~7.47 ng·g-1(ww),浮水植物中HCHs含量最高,挺水植物各组织含量也有明显差异,根部HCHs含量明显高于茎叶2种组织。2)4种HCHs异构体中,γ-HCH的残留水平要显著高于其他3种异构体。在沉水植物和浮水植物中,均以γ-HCH占绝对比例,相对含量达60%~99%;而在挺水植物中,δ-HCHs占有较高比例,并且主要富集在挺水植物的根部,茎中次之,叶中最少。3)小白洋淀浮水植物和沉水植物HCHs含量与水体中HCHs含量呈显著的正相关关系,而挺水植物荷花、蒲草中HCHs各组分含量与水体中HCHs的相关关系不显著。4)水生植物对水中HCHs的富集系数BCF在8.7~661.2范围;浮水植物的BCF最高,沉水植物次之,挺水植物的茎对水体中HCHs的BCF最低。     

Detection of lipid peroxidation and cytotoxicity induced by aluminium (Al) and cobalt (Co) ions in barbunia root tip cells

The aim of this study was to investigate the cytotoxic effects of different concentrations of Aluminium (Al) and Cobalt (Co) heavy metal ions on Phaseolus vulgaris L. cv Barbunia (Fabaceae) root tips. We used the germination percentage (GP), root length (RL), weight gain (WG) and micronucleus (MN) frequency as indicators of cytotoxicity and correlated these data with statistical parameters. Additionally to the cytogenetic analysis, lipid peroxidation and DNA analyses were performed in root tips of barbunia seeds treated with Al and Co metals. The seeds were divided into five groups as control, Al and Co treatment groups. They were treated with 25 and 50 ppm doses of Al and Co during 7 days. The results indicated that there was an alteration in the GP, RL, WG and MN frequency depending on the treatment dose in the seeds exposed to Al and Co metal ions when compared with the controls. Al and Co metal ions at both the doses significantly reduced the GP, RL and WG in seeds of all the treatment groups. The highest GP was observed in seeds of the control group (in proportion as 96%). 25 and 50 ppm doses of Co and Al caused 30, 50 and 42, 64% decrease of seed germination, respectively. In the control group, the final weights of all the seeds increased about 1.31 g when compared to initial weight. The mean RL of control seeds were measured as 3.71 cm at the end of experimental period. In Co andAl groups, the final weights of seeds increased about 0.34 g and 0.19 g according to initial weight at 50 ppm dose, respectively But, Al and Co ions caused a dose-dependent increase in the frequency of MN. The highest frequency of MN was observed at 50 ppm dose of Al and least frequency of MN was observed at 25 ppm dose of Co. Besides, 25 and 50 ppm concentrations of Al and Co significantly enhanced the lipid peroxidation and caused an increase in malondialdehyde (MDA) levels at both the doses. In roots treated with 25 and 50 ppm doses of Al, the increase of MDA was about 62 and 136% according to control, respectively In Co-treated roots, the increase of MDA was about 31 and 91% according to the control at 25 and 50 ppm doses, respectively The investigated parameters (except MN and MDA) were higher in the seeds exposed to Co than the seeds treated with Al. Moreover, it was observed that the yields of DNA in the seeds treated with Al andCo metals were lower than recorded in the controls. Hence, DNA yields exposed to Al and Co were run ahead on agarose gel according to the control group. The results of the present study indicate that Al and Co metal ions have toxic effects on barbunia root tip cells, and the selected parameters such as the GP, RL, WG, MN and MDA are very sensitive and useful biomarkers for biomonitoring these effects.     

Seed germination of Cistus creticus L. and Cistus laurifolius L. as influenced by dry-heat, soaking in distilled water and gibberellic acid

The effects of dry-heat and seed soaking in distilled water or in gibberellic acid on germination performance of Cistus creticus L. and C. laurifolius L. were studied in the present study Germination percentages of two Cistus species were low due to dormancy Soaking in distilled water for 24 hr resulted in 28% germination in C. creticus and 43% in C. laurifolius. Gibberellic acid applications (20, 100 and 250 mg l(-1)) for 24 hr gave 32, 30 and 23% germination, respectively in Cistus creticus and 33, 37 and 28% germination, respectively in C. laurifolius. Dry-heat pretreatments at 50, 80 and 100 degrees C for several times (1-60 min) also significantly increased germination percentage in two species. The highest germination in C. creticus was obtained with dry-heat at 100 degrees C for 1 or 5 min (80% and 83%, respectively) and in C. laurifolius at 100 degrees C for 5 min (87%). A significant increase in germination rate was also achieved under different pretreatments. The physiological dormancy caused by an impermeable seed coat can be overcome by dry-heat pretreatments in two Cistus species.     

Influence of acorn size and storage duration on moisture content, germination and survival of Quercus petraea (Mattuschka)

This study was conducted to evaluate how acom size (small, medium and large) and acorn storage duration (0, 5 and 17 months) influenced Quercus petraea (Mattuschka) moisture content and germination. Acorn size and storage duration did not significantly affect acorn moisture content, but they significantly affected acorn germination performance. When averaged for three acorn sizes, loss of germination performance occurred after 17 months of storage even when the moisture content did not reduce significantly and remain at the initial level (32.6%). Maximum germination percentage was observed in large and medium size classes before storage (93 and 95%, respectively) and after 5-month storage (94 and 93%, respectively), but after 17-month storage medium acorn size class exhibited the highest germination (68%). Small seed size class exhibited the lowest germination percentage and rate in each acorn storage duration. Acorn size also significantly affected seedling emergence and survival in the nursery and seedling emergence and survival was the lowest in small seed size class (85 and 80%, respectively). Although seedling survival of one-year seedlings in the nursery increased up to large seed size class, maximum survival in nursery conditions was observed in large and medium size classes (89 and 91%, respectively). Thus, acorn size grading in Q. petraea may result in higher germination performance within in a seedbed.     

Phytostabilization of mine waste: growth and physiological responses of Vigna unguiculata (L.) Walp

Greenhouse experiments were carried out for phytoremediation of the Pb/Zn abandoned tailings (pH 3.2 and high metal content) of Rampura-Agucha Mines, Rajasthan. Vigna unguiculata (L.) Walp. (cowpea) was chosen as a test crop. On unamended tailings, the seeds of the test plant showed no germination. The tailing was amended with lime (3% on weight basis), 3% lime + NPK (diammonium phosphate at 60 kg/ha, muriate of potash at 40 kg/ ha) and 3% lime + FYM at 15 t/ha and used for experiments. Quantification of various parameters viz. shoot-root length, shoot-root dry weight, chlorophyll contents (a', 'b' and total) and peroxidase activity of test crop revealed T+ S + 3% lime + NPK to be the most suitable amelioration followed by FYM. The above treatments helped in improving the growth and productivity of the test plants by providing a favorable environment.     

金莲木（Ochna integerrima（Lour．）Merr．）的生态生物学特征及其播种繁殖技术

金莲小（Ochnaintegerrima（Lour．）Merr．）足金莲术科落叫淞小或小乔小,址潜在的优良Ⅲ林绿化树种．文章从其形态解削特,其光合生理生态特征及播种繁殖技术方面进行了系统的研究。结果表明：金莲小为rft性偏阳性树种,光合速率LI进秤星单峰曲线,尤午休现象;其光饱和点（LSP）和I光补偿点（LCP）分别在800μmol·m^-2.s^-1及52．2μmol·m^-2．s^-1左右、在高于光饱和点的光强下,其叶片的光合速率并未出现叫娃下降趋势,州时还维持了较i舟的蒸腾速率,、金莲小叶绿素荧光参数显水其具有较高的能精利用效率,叶绿素a／b比值（5．677：1）略高于理论价（3：1）,表明它能有效吸收比能许传到光反应叭tl山。播种前金莲小种子宵进行浸泡处理,浸泡24h处理后足发芽率高日．发芽较早,播种住泷炭土中的种f较沙土中的种子发芽要甘H荫发周期短,但往沙土中播种的种子最终的发芽率耍相对较高。、㈧此,金莲l术适合生长存水热充沛、土壤十}1对JJ巴沃的热带亚热带地区,栽培时要尽量选择十层肥沃的壤土或砂质壤土。金莲术（Ochnaintegerrima（Lout．）Merr．）是金莲术科落叶灌本或小乔木,是潜在的优良冈林绿化树种。文章从其形态解剖特征、光合生理生态特征及播种繁殖技术方面进行了系统的研究。结果表明：金莲木为中性偏阳性树种,光合速率日进程呈单峰曲线,无午休现象;其光饱和点（LSP）和光补偿点（LCP）分别在800μmol·m^-2．s^-1及52．2μmol·m^-2．s^-1左右。在高于光饱和点的光强下,其叶片的光合速率并未出现明显下降趋势,同时还维持了较高的蒸腾速率。金莲术叶绿素荧光参数显示其具有较高的能量利用效率,叶绿素a／b比值（5．677：1）略高于理论值（3：1）,表明它能有效吸收光能并传到光反应中心。播种前金莲木种子宜进行浸泡处理,浸泡24h处理后其发芽率高且发芽较早,播种在泥炭土中的种子较沙土中的种子发芽要早且萌发周期短,但在沙土中播种的种子最终的发芽率要相对较高。因此,金莲木适合生长在水热充沛、土壤相对肥沃的热带亚热带地区,栽培时要尽量选择土层肥沃的壤土或砂质壤土。     

The investigation of cytotoxic effects of refinery wastewater on root tip cells of Vicia faba L

The present study was carried out to evaluate the cytotoxic effects of refinery wastewater collected from different stations of the Kizilirmak river on Vicia faba L. root tip cells. For this aim, we used the germination percentage, root length, weight gain and micronucleus (MN) frequency as indicators of cytotoxicity. Additionally to the cytological analysis, DNA analyses were performed in root tips meristems of Vicia faba seeds treated with refinery wastewater. Heavy metal concentrations in the water samples were determined using atomic absorption spectrophotometer (AAS). The concentrations of heavy metals in the water were in the order of Pb>Zn>Fe>Cu>Ni>Cd>Hg. The highest germination percantage was observed in the control group (in proportion as 96%). Heavy metals in the water samples collected from Station I, II and III caused a decrease in the germination percentage as 48, 18 and 30%, respectively. The highest root length and weight gain was observed in the control group at the end of the experimental period. The least root length and weight gain was observed in seeds treated with wastewater collected from Station I. In the control group, the weights of all the seeds increased about 4.08 g when compared with initial weight. The root lengths of the control seeds were determined as 6.38 cm at the end of the experimental period. The weights of the seeds exposed to wastewaters obtained from Station I, II and III increased about 1.08, 3.03 and 2.01 g according to initial weight, respectively. Microscopic examination of V. faba root tip meristem cells showed that any example of the MN formation was not seen in the control group. The highest frequency of MN was observed in group treated with wastewater collected from Station I and least frequency of MN was observed in group treated with wastewater collected from Station II. It was also observed that the yields of DNA in the seeds exposed to wastewater were lower than recorded in the controls. Hence, DNA yields exposed to wastewater were run ahead on agarose gel according to the control group. The results clearly indicate that refinery wastewater had important cytotoxic effects on V. faba root tip cells. It was also observed that V. faba seeds are very sensitive and useful biomarkers for monitoring these effects in waters contaminated with heavy metals.     

Impacts of crude oil on the germination and growth of cress seeds (Lepidium sp.) after bioremediation of agricultural soil polluted with crude petroleum using "adapted" Pseudomonas putida

The impacts of crude oil on the germination, growth and morphology of cress seeds (Lepidium sp.) after bioremediation of agricultural soil polluted with crude petroleum using "adapted" Pseudomonas putida (PP) were examined for 15 days. At day 15 there was 100% germination in the untreated control samples, the mean height of the seedlings was 75.8 +/- 2.6 mm and all appeared to have grown morphologically normal. In the experimental samples treated with oil and PP inoculation, there was 98% germination and the seedlings reached a height of 63.8 +/- 6.9 mm; again, morphologically the seedlings appeared normal. However, in the control samples treated with oil but without PP inoculation, there was 31-38% germination and seedling heights of 34.2 +/- 11.4-42.3 +/- 8.5 mm with abnormal morphology. Treatment of oil-impacted agricultural soil with PP as a bioremediation agent does produce soil which is capable of growing larger and healthier plants than where bioremediation has not taken place.     

Seed germination in response to chemicals: effect of nitrogen and pH in the media

Seed germination generally presents a peak in the next growing season after a fire. Among other factors associated with fire are the increase of soil nitrogen and changes in the pH of the soil. In this study, we addressed the question, whether or not the germination response of eight species is linked with the increase in pH and nitrogenous compounds in the germination media? We assessed the separate and combined effects of nitrogenous compounds and pH on the percentage and rate of germination of seeds of Medicago arabica (L.) Hudson, Epilobium hirsutum L., Foeniculum vulgare Miller, Daucus carota L., Thapsia villosa L., Cynosurus cristatus L., Dactylis glomerata L. and Rumex crispus L. All these species are well represented in the Mediterranean ecosystems of the central-west Spain. Water and CaCl2 were used as controls. Nitrogenous compounds increased percent germination (level) and rate in three of the species studied. High pH negatively affected the germination rate of seeds from most species, but had no effect on the per cent germination of any of the species. The higher concentration of the nutritious solutions affected negatively the germination level and rate. The different germination responses of seeds of the studied species could not be exclusively attributed to pH values in the media, whereas the amount and form of Nitrogen in the media has a greater effect on it. These differences in germination are species dependent.     

ZnO NPs对水培小麦(Triticum aestivum L)种子不同发育阶段的影响

氧化锌纳米颗粒(ZnO NPs)是目前应用最为广泛的纳米材料之一,已有研究表明其对生物体具有显著的毒性效应。为了研究ZnO NPs的毒性与种子发育阶段的关系,选择小麦(Triticum aestivum L)作为受试植物,将处于不同发育阶段的小麦种子置入ZnO NPs悬浮液中进行培养,研究了ZnO NPs对水培小麦种子不同发育阶段的影响。结果表明,虽然ZnO NPs对处于吸胀阶段、萌动阶段和发芽阶段的小麦都可以产生毒性,但是毒性的大小随小麦发育阶段的不同而表现出明显的差异(P0.05)。在60 mg·L-1暴露浓度下,用ZnO NPs对处于吸胀阶段、萌动阶段和发芽阶段的小麦种子进行处理,小麦根长的抑制率分别为37.8%、80.2%和95.7%;就萌动阶段和发芽阶段而言,ZnO NPs的毒性与其浓度有关,浓度越大毒性越大,即具有显著的浓度效应。上述研究结果对于全面准确地评价ZnO NPs毒性具有重要的意义。     

极低频电磁场对萌发期大豆的生物学效应

观察了50Hz.0.2mT或6.0mT的电磁场暴露对大豆的萌发过程，丙二醛（MDA）含量，超氧化物歧化酶（SOD），过氧化氢酶（CAT），过氧化物酶（POD），蛋白酶活性和可溶性蛋白含量以及幼苗根茎的组织形态学影响。结果表明：电磁场暴露下，大豆的开始萌发时间由32h提前到8h，萌发率到达50％的时间由72h分别提前到48h(0.2mT组）和40h(6.0mT组）；MDA含量随磁场强度的增大而下降；SOD，POD活性随磁场强度的增大而升高，而CAT活性在0.2mT暴露组下降，在6.0mT暴露组升高；蛋白酶活性和可溶性蛋白含量分别随磁场强度的增大升高或降低。幼苗根茎细胞的大小和形态没有明显变化。结果提示，极低频电磁场可以改变抗氧化酶的活性，减缓脂质过氧化，增强蛋白酶的活性，促进大豆的萌发过程。图4参6。