PEG胁迫对西伯利亚冰草种子萌发及幼苗生理特性的影响

以PEG-6000模拟干旱胁迫,分析西伯利亚冰草种子发芽率、发芽势、胚根和胚芽长及三叶期幼苗相对电导率、丙二醛和游离脯氨酸含量的动态变化规律.结果表明:1)高渗透势PEG溶液(-0.2,-0.4 MPa)能够促进种子萌发,在-0.4 MPa时,发芽率和发芽势均达到峰值.2)高渗透势PEG溶液(-0.2,-0.4,-0.6 MPa)对胚根伸长具有一定的促进作用,-0.4 MPa最大,但对胚芽表现出一定的抑制作用.3)随着渗透势的降低,发芽率、发芽势、胚根长和胚芽长不断下降,胚根/胚芽的比值持续上升.4)3叶期幼苗相对电导率、丙二醛和脯氨酸含量随胁迫强度的增加,胁迫时间的延长持续增加,相对电导率、丙二醛含量除了-0.4 MPa,1d处理外,其他处理均极显著(p＜0.01)高于对照,脯氨酸含量各处理均极显著(p＜0.01)高于对照,相对电导率、丙二醛和脯氨酸这3个指标均可作为抗旱性评价指标.     

Effect of Water Stress on Physiological Attributes and their Relationship with Growth and Yield of Wheat Cultivars at Different Stages

The effects of water stress on physiological attributes of drought‐sensitive (Kalyansona) and drought‐tolerant (C‐306) wheat cultivars were studied in a pot experiment. Water stress was imposed by withholding irrigation at boot and anthesis stages. Leaf water potential, leaf osmotic potential and leaf turgor potential (measured with pressure chamber and osmometer), as well as leaf diffusive resistance, leaf transpiration rate and leaf‐to‐air transpiration gradient (measured with a steady‐state porometer) were measured diurnally. Growth and yield parameters were recorded after harvesting of the crop. Triplicate data were analysed using a completely randomized design and correlations amongst these parameters were computed. Water stress was found to reduce diurnal leaf water potential and leaf osmotic potential in both the genotypes but leaf osmotic potential was significantly higher in the drought‐tolerant cultivar C‐306 than in the drought‐sensitive cultivar Kalyansona. Positive turgor was recorded in both the genotypes under water stress and non‐stress conditions. Water‐stressed plants showed significantly lower turgor potential than control plants. In diurnal observations, water‐stressed plants exhibited significantly higher leaf diffusive resistance in both genotypes at both stages. The diffusive resistance of C‐306 was predominantly higher than that of Kalyansona. Water stress decreased leaf transpiration rate at both stages but the reduction was higher at the anthesis stage. The leaf‐to‐air temperature gradient was much higher in C‐306 than in Kalyansona at the boot stage but at the anthesis stage genotypic variation was non‐significant. The capacity to maintain cooler foliage was lower at the anthesis stage than at the boot stage in both the cultivars. Shoot dry weight, number of grains, test weight, grain yield, biological yield and harvest index decreased to a greater extent when water stress was imposed at the anthesis stage, while imposition of water stress at the boot stage caused a greater reduction in plant height and number of tillers. Similarly, water stress caused a smaller reduction in growth, yield and yield attributes in C‐306 than in Kalyansona. In general, the correlation coefficient of grain and biological yield with water potential and its components was positive and highly significant. Similarly, turgor potential was also correlated positively and significantly with grain yield at both the stages, but with biological yield it was significant only at the anthesis stage. A negative and significant correlation was obtained for diffusive resistance and leaf‐to‐air temperature gradient with grain yield at the boot and anthesis stages. The rate of transpiration was also positively and significantly correlated to grain and biological yields at both the stages. Amongst the yield attributes, number of leaves and number of tillers were positively correlated at the anthesis stage, whereas leaf area and shoot dry weight were significantly correlated with grain and biological yields at both the stages.     

热应激奶牛血清NO浓度和NOS活力的变化

为探索不同品种奶牛血清中一氧化氮合成酶（NOS）的活力以及一氧化氮（NO）浓度变化与热应激的关系。此实验在热应激期（THI 82.61±0.60）和非热应激期（THI 47.42±0.51）对荷斯坦牛（n=20）和娟-荷F1牛（n=20）血清NOS活力及NO浓度水平进行测定。结果表明：荷斯坦牛和娟-荷F1牛在热应激期血清NOS的活力均显著低于非热应激期（P〈0.01）;热应激期娟-荷F1牛血清NOS的活力显著低于荷斯坦牛（P〈0.01）,非热应激期二者差异不显著（P〉0.05）;热应激期荷斯坦牛血清NO浓度较非热应激期显著降低（P〈0.05）,娟-荷F1牛有降低趋势,但差异不显著（P〉0.05）;非热应激期荷斯坦牛血清中NO浓度显著高于娟-荷F1牛（P〈0.05）,热应激期二者差异不显著（P〉0.05）。     

渗透胁迫下小麦幼苗CaM含量变化及其与含水量的关系研究

试验研究结果表明,PEG-6000(-0.73MPa)渗透胁迫下小麦幼苗含水量降低,胁迫12h时叶片钙调素(CaM)迅速增加,之后低于对照,而根系在胁迫12h时钙调素含量降低,胁迫48h时达到高峰后迅速下降。渗透胁迫下氯丙嗪(100μmol/L)降低叶片相对含水量及干物质量,增大根系质膜透性,抑制根系和叶片的伸长。     

水杨酸与CaCl2复配诱导黄瓜幼苗抗复合逆境效果研究

以黄瓜(Cucumis sativusL.)为材料,采用根际注射结合叶面喷洒的方法,研究了水杨酸(Salicylic Acid,SA)与氯化钙(Calcium Chloride,CaCl2)复配对盐胁迫、灰霉病菌侵染复合逆境下黄瓜幼苗的诱抗作用。结果表明:SA与CaCl2复配处理使黄瓜幼苗的盐害和病情指数最高分别比对照降低了28.81%、23.21%,提高了黄瓜叶片中可溶性糖、木质素含量,最高分别比对照增加了44.51%、25.81%,降低了电解质渗出率和丙二醛(MDA)含量,最高分别比对照降低了31.17%、35.45%,增强了超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、苯丙氨酸解氨酶(PAL)和多酚氧化酶(PPO)活性。SA与CaCl2复配处理的抗盐效果低于CaCl2单一处理,抗病效果低于SA单一处理。综合作用效果,SA与CaCl2复配表现为拮抗作用。     

盐胁迫对三种盐生禾草种子萌发及其胚生长的影响

采用不同浓度的NaCl、Na₂CO₃和二者混合盐的胁迫,对羊草、野大麦和朝鲜碱茅种子的发芽率、发芽速度、胚根和胚芽的影响以及盐胁迫解除后的发芽率、胚根和胚芽的生长进行测定与分析。结果表明,随着Na₂CO₃和混合盐溶液浓度的增加,羊草和野大麦种子的发芽率、发芽速度、胚根和胚芽的相对生长均呈下降趋势;而12.5mmol/LNaCl和37.5mmol/LNa⁺混合盐的低浓度胁迫对朝鲜碱茅种子的萌发、胚根和胚芽的生长有促进作用,但发芽速度则随着盐浓度的升高而降低;Na₂CO₃溶液对3种禾草胚根和胚芽的生长均有明显的抑制作用;3种盐分胁迫对羊草和朝鲜碱茅胚根生长的影响均大于胚芽生长;朝鲜碱茅种子萌发时的耐盐性强于野大麦和羊草;盐胁迫解除后,3种禾草的发芽率随原胁迫盐浓度的增加呈升高趋势。     

高温逆境对黄金葛叶片中渗透调节物质积累的影响

以3~5个叶片的黄金葛扦插苗为试材,采用单因素随机区组设计,设4个温度处理,3次重复,测定不同温度、不同时间处理下黄金葛叶片内渗透调节物质含量的变化。结果表明,在同一时间高温胁迫下,随温度的不断升高,黄金葛叶片的可溶性蛋白含量整体呈下降趋势,可溶性糖含量呈上升趋势;同一温度处理下,在35℃,不同时间处理可溶性蛋白含量和可溶性糖含量变化不大,在45℃处理40 h,可溶性蛋白含量比胁迫初期降低了35.02%,而可溶性糖含量比胁迫初期增加了97.06%。     

冷激对贮藏白果多聚半乳糖醛酸酶的影响

以白果 (Ginkgo bilba L.)为材料 ,以 0℃冰水混合物为冷却介质 ,研究了不同冷激处理对贮藏期间多聚半乳糖醛酸酶 (PG)活性的影响 .结果表明 ,冷激能显著抑制 PG活性 ,抑制程度随冷激处理时间的延长而加强 .     

Effect of animal age,postmortem chilling rate,and aging time on meat quality attributes of water buffalo and humped cattle bulls

The study was aimed to investigate the influence of animal age, post‐slaughter chilling rate, and aging time on meat quality of M. longissimus dorsi (LD) of water buffalo (Bubalus bubalis) and humped cattle (Bos taurus indicus) bulls. After slaughtering, one side of carcasses was subjected to rapid chilling (RC) (0 ± 2°C) and other side was hanged in controlled room temperature (25 ± 2°C) for 3 hr, then allowed to the chiller (0 ± 2°C). The meat quality traits were analyzed at 1, 7, and 14 days of storage. It was noted that rapidly chilled carcasses from the younger animals of both species missed the ideal pH/temperature window, which affects the toughness of the meat. Buffalo meat presented higher shear force, color L* values, and lower b* value as compared to the cattle meat. Moreover, meat shear force values decreased while all color coordinates and cooking loss values increased with lengthening the storage time in both age groups of cattle and buffalo. In conclusion, the tenderness of cattle meat was superior to that of buffalo and RC adversely affect the shear force values of young cattle and both age groups of buffalo bulls.     

外源硅对PEG胁迫下小麦幼苗生长及抗氧化酶活性的影响

以德抗961(DK961)和泰山9818(TS9818)为试验材料,研究不同浓度外源硅对PEG胁迫下小麦幼苗的生长及抗氧化酶活性的影响。结果表明:与单纯PEG胁迫相比,外源硅浓度为1.0 mmol·L~(-1)时,DK961和TS9818的鲜重、干重及根系活力均最大,细胞膜透性最小,鲜重分别增加了32.85%和49.43%,干重分别增加了24.14%和50.00%,根系活力分别增加了18.97%和15.60%,细胞膜透性分别降低了12.53%和10.48%;外源硅浓度为0.5 mmol·L~(-1)时,DK961和TS9818的SOD、CAT活性均最大,分别增加了18.11%、19.71%和47.41%、44.51%;外源硅浓度分别为0.5 mmol·L~(-1)和0.1 mmol·L~(-1)时,DK961和TS9818的POD活性最大,MDA含量最低,POD活性分别增加了18.41%和13.02%,MDA含量分别降低了11.80%和12.31%。较低浓度的外源硅能有效促进PEG胁迫下小麦幼苗的生长,增加抗氧化酶活性,降低丙二醛含量。外源硅能够缓解干旱胁迫对小麦幼苗的危害,提高小麦抗旱能力。