Effects of Accelerated Aging on Physiological and Biochemical Characteristics of Waxy and Non-waxy Wheat Seeds

Experiments were conducted to evaluate the physiological and the biochemical characteristics of waxy wheat seeds under accelerated aging conditions. Five waxy wheat lines, which were Waxy 1, Waxy 4, Waxy 8, Waxy 9, and Waxy 15; and five non-waxy wheat lines： S-39, 04J89, Jan-81, III42-4, and II110 were studied. The seeds were subjected to accelerated aging at 40℃, 45℃, 50℃, 55℃, and 60℃, and 90% relative humidity for 0, 2, 4, 6, and 8 days, respectively. The results showed a gradual increase in conductivity and decrease in germination rate during accelerated aging. SOD, POD and CAT activities increased at lowgrade treatment, but decreased at severe treatment. On the other hand, the soluble protein content decreased at 45 ℃, but successively increased, then decreased 50℃. From the above study, it showed that 90% RH at 55℃ was the best accelerated aging condition for optimum efficiency in a shorter period.

Physiological and Biochemical Characteristics in Flag Leaves of the C Liangyou Series of Hybrid Rice Combinations at Late Growth Stages

The contents of chlorophyll, soluble sugars, soluble proteins and thiobarbitudc acid reaction substance （TBARS）, chlorophyll fluorescence parameters, net photosynthetic rate as well as the activities of superoxide dismutase （SOD） and peroxidase （POD） of flag leaves at the late growth stages were studied by using C Liangyou series of hybrid rice combinitions as material and Shanyou 63 as control. The C Liangyou series of hybrid rice combinations used in the experiment included C Liangyou 396, C Liangyou 87, C Liangyou 755 and C Liangyou 34, which all used C815S as male sterile line. The contents of chlorophyll, soluble sugars and soluble proteins in flag leaves of the C Liangyou series combinations at the late growth stages were higher than those of the control, whereas the TBARS content was lower than that of the control. The activities of SOD and POD were significantly higher than those of the control on the 7th day after heading, and then decreased slowly. ~bps, value and qp value of flag leaves decreased at the late growth stages, and these two parameters in flag leaves of the C Liangyou series combinations were higher than those of the control, while the qN value increased at the late growth stages and was lower than that of the control. The net photosynthetic rate of flag leaves at the late growth stage was higher compared with the control. These results suggest that slow senescence and strong photosynthetic capability in flag leaves at the late growth stages are the physiological basis of the C Liangyou series combinations.

Changes in Physiological and Biochemical Characteristics of Floral Organ Development in a Soybean Cytoplasmic-nuclear Male Sterile Line

[Objectives]This study was conducted to explore the mechanism of soybean cytoplasmic-nuclear male sterility.[Methods]With soybean cytoplasmic-nuclear male sterile line JLCMS9 A and its homotype maintainer line JLCMS9 B as experimental materials,the activity of superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT),malondialdehyde(MDA)content,starch content,soluble protein content,soluble sugar content and free proline content in flower buds,alabastrums and mature flowers were determined,and the contents and changes of auxin(IAA),gibberellin(GA3),isopentenyl adenosine(iPA)and abscisic acid(ABA)at the three stages were analyzed.[Results]The activity of SOD and CAT and the contents of MDA and free proline in the sterile line at the flower bud stage were lower than those of the maintainer line,but the opposite was true at the alabastrum stage and the flowering stage,and their values were higher than those of the maintainer line;the POD activity of the sterile line was significantly lower than that of the maintainer line at the flower bud stage,and the opposite was true at the alabastrum stage and the flowering stage,and its values were higher than those of the maintainer line;and the starch content and soluble sugar content of sterile line 9 A showed an overall upward trend,and were significantly lower than those of the maintainer line 9 B at the alabastrum stage and the flowering stage.During the whole development process of floral organs,the content of IAA in sterile line 9 A showed a trend of first increasing and then decreasing,and the content of iPA increased gradually.The contents of hormones in the sterile line were lower than those in the maintainer line.The ratios of IAA/ABA,IAA/GA3,IAA/iPA and ABA/GA3 in the sterile line were significantly different from those in the maintainer line.It is inferred that the abnormal physiological characteristics of floral organ development are related to the cytoplasmic-nuclear male sterility of soybean.The alabastrum stage may be a critical period for the occurrence of abnormal physiological and biochemical indexes in the floral organs of soybean cytoplasmic-nuclear male sterile lines.[Conclusions]This study provides a theoretical basis for the breeding of fine sterile lines of soybean and the research on the mechanism of sterility.

Effect of La-Gly on Physiological and Biochemical Characteristics of Glycine max Seedling under Pb Stress

The physiological and biochemical characteristics of Glycine max seedlings were changed under the high concentration of Pb stress, in which the malony dialdehyde (MDA) content, plasmalemma, activities of catalase (CAT) and peroxidase (POD) were increased drastically. The damage effects of Pb were reduced when 15 mg . L-1 La-Gly was used to spray Glycine max seedlings. The results of La-Gly treatment show that the effects are related to the decrease of Pb content in plants, the increase of photosynthetic rate and nitrate reductase (NR) activity, decrease of MDA content and cell membrane permeability, and maintenance of activities of CAT and POD.

Impacts of X-ray irradiation on Saccharomyces cerevisiae cells growth and physiological-biochemical characteristic

In this paper, the growth curves of yeast cells exposed to X-rays were detected, and then fitted by Gompertz equation. The yeast cells treated with 50–125 Gy showed an increased exponential growth rate, and lower total biomass at plateau. At doses ≥ 150 Gy, cells showed a decreased exponential growth rate and higher total biomass at plateau. DNA lesions were detected by comet assay. Meanwhile, intracellular accumulation of reactive oxygen species(ROS), reduction of mitochondrial membrane potential(?Ψ m) and cell membrane integrity were evaluated. We conclude that X-ray irradiation results in DNA lesions, ROS accumulation and?Ψ m decline in a dose-dependent manner, and that these changes may be one of causes of X-rays-induced apoptosis in yeast. Furthermore, yeast cell membrane integrity appeared compromised following irradiation,suggesting that membrane damage may also have a role in the biological effects of radiation.

Effects on Zinc Stress on Stress-Resistance Physiological and Biochemical Indexes of Jatropha curcas seedlings

Jatropha curcas seedlings were cultured for 21 d under 6 zinc concentrations of 0,25,50,100,200,400 mg/l to study the effects of ZnS O4 stress on the mechanism of resistance to heavy metal stress of J. curcas seedlings. The results showed that with the increase of stress concentration,the content of chlorophyll-a decreased and the activity of POD first increased and then maintained at a certain level or decreased slowly. The contents of soluble sugar,malondialdehyde,soluble protein and free proline increased,and the root activity increased first and then decreased. The relative conductivity of J. curcas seedlings decreased first and then increased,which indicated that the leaves of J. curcas seedlings had some adaptability and self-repairing capability under zinc toxicity stress,but the adaptability and self-repair ability were limited.

Acclimation and Tolerance Strategies of Rice under Drought Stress

Rice （Oryza sativa L.） is an important food crop and requires larger amount of water throughout its life cycle as compared to other crops. Hence, water related stress cause severe threat to rice production. Drought is a major challenge limiting rice production. It affects rice at morphological （reduced germination, plant height, plant biomass, number of tillers, various root and leaf traits）, physiological （reduced photosynthesis, transpiration, stomatal conductance, water use efficiency, relative water content, chlorophyll content, photosystem II activity, membrane stability, carbon isotope discrimination and abscisic acid content）, biochemical （accumulation of osmoprotectant like proline, sugars, polyamines and antioxidants） and molecular （altered expression of genes which encode transcription factors and defence related proteins） levels and thereby affects its yield. To facilitate the selection or development of drought tolerant rice varieties, a thorough understanding of the various mechanisms that govern the yield of rice under water stress condition is a prerequisite. Thus, this review is focused mainly on recent information about the effects of drought on rice, rice responses as well as adaptation mechanisms to drought stress.

Isolation and identification of moderately thermophilic acidophilic iron-oxidizing bacterium and its bioleaching characterization

A moderately thermophilic acidophilic iron-oxidizing bacterium ZW-1 was isolated from Dexing mine, Jiangxi Province, China. The morphological, biochemical and physiological characteristics, 16S rRNA sequence and bioleaching characterization of strain ZW-1 were studied. The optimum growth temperature is 48 ℃, and the optimum initial pH is 1.9. The strain can grow autotrophically by using ferrous iron or elemental sulfur as sole energy sources. The strain is also able to grow heterotrophically by using peptone and yeast extract powder, but not glucose. The cell density of strain ZW-1 can reach up to 1.02×108 /mL with addition of 0.4 g/L peptone. A phylogenetic tree was constructed by comparing with the published 16S rRNA sequences of the relative bacteria species. In the phylogenetic tree, strain ZW-1 is closely relative to Sulfobacilus acidophilus with more than 99% sequence similarity. The results of bioleaching experiments indicate that the strain could oxidize Fe2+ efficiently, and the maximum oxidizing rate is 0.295 g/(L·h). It could tolerate high concentration of Fe3+ and Cu2+ (35 g/L and 25 g/L, respectively). After 20 d, 44.6% of copper is extracted from chalcopyrite by using strain ZW-1 as inocula.

Physiological Responses of Dendrobium officinale under Exposure to Cold Stress with Two Cultivars

This study aimed to explore the cold tolerance of two cultivars of Dendrobium officinale(MG1,MG2)grown in different regions of China.Under-2℃ incubation,cultivar MG1 remained active after 3 d,and continued to grow after returning to room temperature.However,MG2 could only maintain its activity after 2 d treatment at−2℃,and the seedlings died with the low temperature treatment time.Investigation of the characteristics of the plants grown in the south(Hangzhou)or north(Zhengzhou)of China indicated that the leaves of MG1 also had reduced stomatal density,the highest thickness,and a compact microstructure.The contents of proline and soluble sugars were higher in MG1 than those in MG2.The cultivar MG1 had higher SOD enzyme activity than MG2,while CAT and POD activities in samples from Zhengzhou were higher than those from Hangzhou.The contents of polysaccharides and alkaloids in stems of in MG1 were higher than those in MG2,while the content of flavonoids in the Zhengzhou samples was higher than that in the Hangzhou samples.In addition,plant heights,stem diameters,and chlorophyll content were higher in MG1.Overall,MG1 had better cold resistance than MG2.MG1 is a cold tolerant cultivar with thick leaves and reduced stomatal density,higher contents of soluble sugars,proline,CAT,POD,polysaccharides,flavonoids and alkaloids,which together make it more adaptable to low temperatures.Thus,the cultivar MG1,with its demonstrated cold tolerance,can accordingly be grown on a large scale in cold regions,thereby expanding the available planting area for this important traditional medicinal plant to meet the increasing commercial demand for it.

Effects of Silicon on Physiology and Biochemistry of Dendrobium moniliforme Plantlets under Cold Stress

[ Objective] The study aimed to investigate the effects of silicon on physiology and biochemistry of Dendrobium moniliforme plantlets under low tempera- ture stress. [ Method ] By using Dendrobium monilforme as the experimental material, different concentrations of Na2SiO3 （0, O. 2, 0.4, 0.6, 0.8, 1.0, 5.0 and 10.0 mmol/L） was added to the basic medium[ 1/2MS ＋ 6-BA （0.1mg/L） ＋ NAA （ 1 mg/L） ＋ agar （7.2 g/L） ＋ sucrose （30 g/L） ] for tissue culture; af- ter hardening and transplanting, Dendrobium moniliforme plantlets were treated under low temperature stress at 4 ~C for 0, 24 and 48 h, in order to investigate the physiological response of Dendrobium ranniliforme leaves to different concentrations of Na2SiO3. [ Result] Under low temperature stress at 4℃, Dendrob/um mon//i- fortns leaves have certain osmotic regulation ability, and the three osmotic regulation substances show different variation trends at different stages. Appropriate con- centration of NshSiO3 can increase the contents of free proline, soluble sugar and soluble protein to varying degrees, reduce MDA content and further improve the cold resistance of Dendrobium moniliforme plantlets. The order of the effects of Na2SiO~ on various physiological indicators is ： free proline 〉 MDA 〉 soluble sugar （or soluble protein）. According to the correlation analysis among various physiological indicators, free proline, soluble sugar, soluble protein and MDA contents can all be used as reference indicators to identify the cold resistance of Dendrobium moniliforme. [ Conclusion] The addition of Na2SiO3 （0.4 retool/L） can moder- ately decrease the thermal energy for normal growth of Dendrobium moniliforme, which is conducive to reducing the cost of cultivation. Key words Na2SiO3 ;Dendrobium monlifforme;Low temperature stress;Physiological and biochemical characteristics

NaCl胁迫下外源亚精胺对马铃薯幼苗生理特征的影响

【目的】研究NaCl胁迫下外源亚精胺(Spd)对马铃薯幼苗生理特征的影响,为新疆盐渍化区域马铃薯种植提供技术参考。【方法】以晋薯16号马铃薯幼苗为材料,采用不同浓度NaCl模拟盐胁迫处理,研究外源亚精胺Spd对马铃薯植株生长、叶片抗氧化酶活性、渗透调节物质含量的影响。【结果】盐胁迫抑制了马铃薯植株生长,使得超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)等酶促类抗氧化酶活性表现为低盐胁迫促进,高盐胁迫抑制;抗坏血酸(ASA)、谷胱甘肽(DSH)等非酶促类抗氧化酶含量均降低;脯氨酸、可溶性糖、氨基酸含量升高;外源亚精胺(Spd)通过提高叶绿素含量、根系活力,调节渗透调节物质含量,增强抗氧化酶活性等方式维持植物体的正常生理代谢功能。【结论】外源亚精胺(Spd)可提升马铃薯耐盐性,缓解盐胁迫对马铃薯植株的抑制作用,其中0.9 mmol/L Spd(S 3)浓度缓解效果最明显。

7.2%萎锈灵和40%拌种灵包衣对棉花幼苗冷胁迫生理生化特征的功效比较

【目的】研究比较具有活性结构相似的2种杀菌剂萎锈灵和拌种灵包衣棉种提高棉种适应冷胁迫能力功效,分析2种杀菌剂包衣提高棉花适应冷胁迫的能力差异,及其生理作用机制,为开发提高棉花适应冷胁迫能力的新产品提供理论依据。【方法】以新疆北疆棉区主栽品种新陆早50号为材料,以基础种衣剂包衣棉种为对照,将萎锈灵和拌种灵分别添加到基础种衣剂中分别制成7.2%萎锈灵和40%拌种灵的种衣剂进行包衣,采用人工模拟低温环境(4℃/16℃)进行低温胁迫处理,观测各包衣处理对低温条件下棉花萌发、幼苗生长情况和耐冷性的生理响应。【结果】与对照比较,萎锈灵和拌种灵包衣处理的发芽势分别增加9.67%和5.33%;发芽指数分别增加12.00%和6.00%,活力指数分别增加13.33%和6.67%,电导率REC分别增加-12.5%和-3.75%,可溶性蛋白SP含量分别增加11.00%和6.00%,超氧化物岐化酶SOD活性分别增加10.67%和6.67%,冷胁迫指数CI分别降低-10.67%和-5.33%,且差异均显著;棉苗CI与REC、SP、SOD等指标呈显著相关性;萎锈灵包衣处理提高棉花幼苗生长适应冷胁迫能力优于拌种灵。【结论】在冷胁迫下,萎锈灵和拌种灵包衣处理均对棉花种子萌发和幼苗的生理特征有一定影响,能促进萌发期种子内营养物质的转化与合成,提高种子活性,从而提高种子的发芽率,通过诱导棉花幼苗细胞内部酶的活性增强,清除幼苗体内活性氧自由基,加快丙二醛MDA含量的积累,保护幼苗细胞膜结构稳定性,从而提高棉苗适应冷胁迫的能力。2种药剂中,萎锈灵种衣剂诱导棉苗适应冷胁迫效果优于拌种灵。

不同成熟期对花椰菜种子活力及相关生理生化指标的影响

花椰菜种子收获时常依据经验进行,易导致采收时期不当,对种子质量造成较大的影响。为研究花椰菜杂交种子成熟期与种子活力的关系,确定适宜的种子收获期,本研究以花椰菜品种瓯松60天为材料,分析了授粉后40、45、50、55、60、65 d不同成熟期种子物理性状、种子活力和抗氧化酶活性等指标变化。结果表明,随着种子成熟期延长,种子含水量、鲜种子千粒重呈降低趋势,种子浸泡液电导率和丙二醛(MDA)含量先降低后趋于稳定,规定水分千粒重、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、发芽率、发芽势、活力指数、苗高、根长先增加后趋于稳定。不同授粉后天数之间比较结果表明,授粉后55、60、65 d,活力指数、苗高和根长差异不显著,但均显著高于50 d;规定水分千粒重、SOD活性、POD活性、MDA含量、电导率在授粉后55 d趋于稳定。回归分析结果表明,活力指数与鲜种子千粒重、种子含水量、MDA含量、电导率显著(P<0.05)或极显著(P<0.01)线性负相关,与SOD和POD活性极显著线性正相关(P<0.01)。活力指数、SOD活性、POD活性、MDA含量、电导率与种子发育天数符合二项式函数变化:y_(活力指数)=-0.131x2+16.957x-344.480,y_(SOD活性)=-0.020x2+2.668x-10.420,y_(POD活性)=-0.112x2+14.417x-368.610,y_(MDA含量)=0.113x2-13.771x+433.780,y_(电导率)=0.088x2-10.319x+338.680,达显著或极显著水平,可用来预测不同发育天数种子的活力、保护酶清除活性氧自由基能力和细胞膜结构的完整性。综上,授粉后55 d,瓯松60天种子已达可采收程度,发芽率98%,规定水分千粒重4.364 g,种子活力和种子生理也趋于稳定,且对幼苗生长没有影响,还可降低种子易落粒损失风险。本研究结果为花椰菜杂交种子适时采收提供了理论依据。

2018—2022年“干旱胁迫对植物的影响研究”可视化分析

【目的】深入了解植物干旱胁迫领域的研究现状、研究热点及未来发展趋势,对我国2018-2022年植物干旱胁迫研究进行文献计量和可视化分析。【方法】利用Citespace和VOSviewer软件,以2018-2022年发表在中国知网(CNKI)和Web of Science(WOS)数据库的植物干旱胁迫研究文献为研究对象,分析我国2018-2022年干旱胁迫对植物生长、生理和基因表达的影响研究热点与趋势。【结果】国内干旱胁迫对植物影响的研究热点主要集中在“干旱胁迫对植物外在形态和叶片内部结构的影响”“干旱胁迫对植物光合特性的影响”“干旱胁迫对植物渗透调节物质和抗氧化酶的影响”及“干旱胁迫对植物基因表达的影响”4个方面。该领域研究重点主要包括干旱或干旱与盐复合胁迫对植物生理生化和抗旱基因的鉴定与转移。其中知网文献的关键词为“耐盐性”“苗期”和“抗旱鉴定”;WOS文献的关键词则是“抗坏血酸过氧化物酶”“水分利用”和“异位表达”。【结论】纳米材料在缓解植物干旱胁迫中的作用、多组学联合分析(基因组、转录组、蛋白组、代谢组)以及转基因、基因编辑、基因沉默等技术在提升植物抗旱性中的综合应用将成为未来研究热点。

不同占空比的脉冲光源对工业大麻生长和生理生化的影响

试验研究室外栽培条件下,利用不同占空比的脉冲光源对工业大麻进行补光,探究其对工业大麻生长发育、生理生化以及主要大麻素含量的影响。结果表明:占空比100%(LED1)和占空比70%(LED2)的光源促进了工业大麻株高、茎粗、SPAD值以及花叶干重和鲜重的增加,但LED2与不补光(CK)差异不显著,而占空比50%(LED3)光源显著降低了工业大麻的株高、茎粗、SPAD值以及花叶干重和鲜重;LED1、LED2和LED3提高了工业大麻叶片中可溶性糖、可溶性淀粉以及游离氨基酸的含量,LED1与CK差异显著,LED2和LED3与CK差异不显著;LED1和LED2显著降低了超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CTA)活性,而LED3显著促进抗氧化物酶(SOD、POD和CTA)的活性;LED1显著降低了四氢大麻酚(THC)和大麻二酚(CBD)的含量,而LED1、LED2和LED3显著提高了大麻萜酚(CBG)的含量。LED1和LED2光源均可以促进工业大麻的生长发育,增加可溶性渗透调节物质含量,降低抗氧化物活性,增加CBG含量,为今后利用节能(占空比)脉冲光源提高工业大麻品质和产量提供理论参考。

外源钙对甘草生长及生理特性的影响

【目的】为揭示宁夏中部干旱带甘草优质高产栽培过程中甘草对不同钙浓度的适应机制,探究了外源钙对甘草生长及生理生化特性的影响。【方法】以乌拉尔甘草为试验材料,设置0(CK)、5(G_(1))、10(G_(2))、15(G_(3))、20 mmol/L(G_(4))5个钙浓度,分析比较了不同浓度外源钙处理下甘草生长、光合特性及抗氧化酶活性的变化,同时采用主成分分析和隶属函数法综合评价出适宜甘草生长的外源钙施用浓度。【结果】随着钙浓度的增加,甘草主根长、主根直径、单根鲜质量呈先增加后下降的趋势,且不同处理之间差异不显著;甘草叶片叶绿素含量、净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、胞间CO_(2)浓度(Ci)、超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性、过氧化物酶(POD)活性整体呈现先升后降的趋势,钙浓度为10 mmol/L时,Tr、Pn、Gs、SOD活性、CAT活性均达到峰值,且Pn、Gs显著高于对照(P<0.05)。MDA含量随着钙浓度的增加呈先下降后上升的趋势,各浓度处理间差异显著(P<0.05),钙浓度为10mmol/L时的MDA含量最低。综合评价结果表明,钙浓度为10mmol/L时,隶属函数值的均值最大,为0.739。【结论】施用外源钙有利于改善甘草的生理生化特性,促进生长发育;10mmol/L钙浓度是甘草生长的最佳施用量,可为干旱地区甘草的栽培模式提供理论依据。

峨眉拟单性木兰雄性不育的细胞形态学及生理生化特性研究

峨眉拟单性木兰(Parakmeria omeiensis)是木兰科(Magnoliaceae)拟单性木兰属(Parakmeria)的常绿乔木,属于国家Ⅰ级保护的极度濒危植物。为探究峨眉拟单性木兰两性花中雄性败育发生的时期及花药不同发育时期的生理生化特性,以两性花中的不育雄蕊和雄花中的可育雄蕊为材料,利用石蜡切片观察2种雄蕊的花药发育过程,并测定不同发育时期的可溶性糖、可溶性蛋白、脯氨酸的含量,分析过氧化氢酶(CAT)、过氧化物酶(POD)的活性。结果表明:(1)不育雄蕊与可育雄蕊在减速分裂时期出现明显差异,不育雄蕊的绒毡层致密、没有发育,四分体未形成,随后解体,花粉囊中无花粉;可育雄蕊的绒毡层和小孢子母细胞发育正常,成熟时花粉囊开裂,花粉粒溢出。(2)不育雄蕊的可溶性糖含量、可溶性蛋白含量、脯氨酸含量,在减数分裂时期、单核期和花粉成熟期都显著低于可育雄蕊。(3)不育雄蕊POD活性整体呈上升趋势,在减数分裂时期、单核期和花粉成熟期都显著高于可育雄蕊;不育雄蕊CAT活性整体呈下降趋势,显著低于同时期的可育雄蕊。综上认为,两性花中雄性败育发生在减速分裂时期,其败育的主要原因是物质能量代谢降低,绒毡层没有进一步发育,不能给小孢子母细胞提供营养物质;过氧化氢酶及过氧化物酶的活性异常,造成细胞内不能及时清除自由基,使小孢子母细胞的减数分裂受阻,无法形成四分体。该研究结果为深入开展峨眉拟单性木兰雄性不育的分子机制、性系统演化机制研究奠定了基础。

盐胁迫对平欧杂种榛根系生理生化特性的影响

以2年生平欧杂种榛‘达维’为试验材料,在水培条件下设置对照、轻度、中度和重度盐胁迫处理(NaCl浓度分别为0、50、100和200 mmol·L^(-1)),研究不同胁迫时间(1、3和7 d)下根系渗透调节物质、膜伤害程度、抗氧化酶活性以及离子特征的变化,探讨耐盐的生理机制。结果表明:盐胁迫显著促进了可溶性糖(SS)和脯氨酸(Pro)的积累。SS随着胁迫时间的延长呈持续增加趋势,Pro在重度胁迫至3 d时显著升高,较胁迫1 d时提高25.9%。相对电导率(REC)和丙二醛(MDA)随着盐胁迫程度的增强均呈不断升高,重度胁迫下二者较对照分别显著提高32.1%和55.6%。REC和MDA随着胁迫时间的延长呈不断升高。随着盐胁迫程度的增强,超氧化物歧化酶(SOD)表现为先下降后上升,过氧化氢酶(CAT)呈不断增加。SOD和CAT对盐胁迫的响应存在时间差异,二者分别在胁迫7和1 d时达到最大值。随着盐胁迫程度的增强,Na^(+)不断升高,K^(+)波动下降,w(K^(+))∶w(Na^(+))表现为不断下降。平欧杂种榛具有一定的耐盐性。轻度胁迫下,幼苗可以通过自身生理生化特性的调节以响应和适应盐胁迫;中度胁迫下,根细胞膜开始受到伤害,但仍能通过积累渗透调节物质和增强抗氧化酶活性来应对盐胁迫;当NaCl浓度达到200 mmol·L^(-1)且胁迫超过3 d时,植物开始遭受盐害。SS、Pro、CAT活性和Na^(+)质量分数可作为平欧杂种榛耐盐性评价的参考指标。

全株水稻表面优势乳酸菌的筛选与鉴定

本试验旨在对全株水稻表面的优势乳酸菌进行分离、筛选与鉴定,以期挖掘出青贮优良菌种资源。利用平板涂布法对全株水稻上的乳酸菌进行分离,以生长速度和产酸能力进行初筛,以抗氧化能力(H2O2耐受能力、DPPH自由基、羟自由基和超氧阴离子自由基清除率)进行复筛,对筛选出的优势乳酸菌进行生理生化特性分析和分子生物学鉴定。结果表明,从水稻植株表面共分离得到154株乳酸菌,培养48 h后,有16株OD_(600nm)值>2且pH值<4的乳酸菌,其中有9株乳酸菌具有抗氧化能力,综合表现最好的菌株是YMA3,对DPPH自由基、羟自由基、超氧阴离子自由基清除率分别为72.23%、72.46%、86.33%。YMA3表现出较强的高温或酸性环境适应性,鉴定为粪肠球菌。

糖料作物对干旱胁迫的形态、生理及基因响应研究进展

在糖料作物的生长发育过程中,干旱缺水会对其正常生长造成一定的影响。在干旱条件下,糖料作物会产生相应的形态特征与生理生化特性的变化,此外,干旱胁迫还会诱导特定基因的表达,这些形态特征与生理生化特性的变化以及相关基因的表达减轻了糖料作物在干旱胁迫条件下所受到的伤害。本文对糖料作物在干旱胁迫下形态特征与生理生化特性的响应以及耐旱调节基因的相关研究进展方面进行了阐述,综述文献表明,目前发现的调控糖料作物干旱胁迫的主要基因类型有:钙依赖蛋白激酶(CDPK)基因、丝裂原活化蛋白激酶(MAPK)基因、AVP1基因及DREB、NAC、WRKY等转录因子基因。可为提高糖料作物耐旱性研究提供参考。