两种暖季型草坪禾草对土壤持续干旱胁迫的生理反应

在土壤含水量不断递减的干旱胁迫条件下,对沟叶结缕草、假俭草的生理反应进行研究.结果表明,恢复供水试验显示,沟叶结缕草的抗旱能力大于假俭草;随胁迫加深,叶片含水量不断下降,水分饱和亏缺增加;脯氨酸(Pro)含量先升后降,但沟叶结缕草的高峰期出现较假俭草迟且含量高,因而可以Pro高峰期出现的早迟及含量高低作为判定抗旱能力的指标之一;根系活力胁迫初期高于对照,以后逐渐下降,但沟叶结缕草维持高水平时间较长;胁迫初期叶片质膜透性(RPP)、丙二醛(MDA)表现为缓慢递增,SOD活性高于对照,当胁迫到一定程度后,RPP、MDA急剧增加,SOD活性急剧下降,但沟叶结缕草能在较长时间内维持SOD活性,RPP、MDA增加幅度较小,这是沟叶结缕草较假俭草抗旱的生理机制之一.     

紫鸭跖草对铜盐胁迫的生理反应

采用Hoagland营养液水培方法在不同CuSO4浓度条件下培养紫鸭跖草,研究紫鸭跖草在Cu胁迫下的生理反应.结果表明:紫鸭跖草抗氧化体系的SOD,APX,GPX和CAT酶活性根部始终高于叶部.在高于250 (mol/L Cu处理时,APX,GPX和SOD酶活性均显著升高,在低于250 (mol/L Cu处理时,只有CAT活性一直随Cu浓度的增大而下降.根部和叶部GR活性在100～250 (mol/L Cu处理时显著高于其他浓度Cu供应水平.GSH含量在250 (mol/L Cu处理时较高;根部脯氨酸含量与Cu供应水平呈线性正相关,而叶部脯氨酸含量与Cu供应水平呈线性负相关.质膜透性和膜脂过氧化研究表明,紫鸭跖草在小于50 (mol/L或大于250 (mol/L Cu供应时分别受到Cu缺乏或中毒胁迫.光合速率和蒸腾速率以及根系活力的研究结果均表明紫鸭跖草在较大浓度Cu供应时生长良好.说明紫鸭跖草相比普通植物,对Cu具有较高的生理需要量.     

水分供应和氮素形态对水稻一些水分生理特征的影响

为探明不同水分供应和氮素形态对水稻一些水分生理特征的影响,设正常水分及50 g L^-1 PEG模拟水分胁迫及3种不同NH₄⁺-N/NO₃^--N比例（75/25,50/50,25/75）的处理,测定了水稻叶片的NO₃^-、Ca²⁺和Mg²⁺含量,叶片浸出液电导率,叶片相对含水量,叶片水分临界饱和亏以及叶片水势。结果表明,在NH₄⁺-N/NO₃^--N比例较低时,模拟水分胁迫使广陵香粳水稻幼苗吸收更多的NO₃^--N。模拟水分胁迫条件下,水稻幼苗叶片浸出液电导率随NH₄⁺-N/NO₃^--N比例的降低呈下降趋势,且在NH₄⁺-N/NO₃^--N比例为25/75时,叶片浸出液电导率低于正常水分培养条件下的叶片浸出液电导率。而在正常水分培养条件下,水稻幼苗叶片浸出液电导率随NH₄⁺-N/NO₃^--N比例的降低呈上升趋势。水分胁迫使高NH₄⁺-N/NO₃^--N处理水稻叶片相对含水量降低、水分临界饱和亏上升,但对低NH₄⁺-N/NO₃^--N处理（25/75）水稻叶片相对含水量和水分临界饱和亏影响很小。同样,低NH₄⁺-N/NO₃^--N处理削弱了水分胁迫对水稻叶片水势的降低。总体上说,低NH₄⁺-N/NO₃^--N能减轻水分胁迫对水稻水分生理的不良影响。     

四种冷季型草坪草对二氧化硫胁迫的生理响应研究

本研究以4种冷季型草坪草高羊茅、多年生黑麦草、匍匐翦股颖、草地早熟禾为材料,采用人工模拟熏气法,以1.45,2.15,3.56和5.01 mg/m³ 4个SO₂浓度水平,测定4种草坪草生理生化指标,最终比较4种草坪草对SO₂的抗性。结果表明,4种草坪草叶绿素含量随着SO₂浓度升高而降低,丙二醛、可溶性糖和脯氨酸随着SO₂浓度升高而增加。而且SOD、POD、CAT活性都随着SO₂浓度升高呈现不同程度的增加。采用模糊数学隶属度对各项指标综合评定得出,4种草坪草对SO₂的抗性能力由强到弱顺序为高羊茅、多年生黑麦草、匍匐剪股颖、草地早熟禾。从这些结果我们可以推断在SO₂污染强的区域,适宜种植高羊茅和多年生黑麦草。     

不同纬度种群日本结缕草对冷胁迫的生理反应

对不同纬度分布的日本结缕草种质资源耐寒性进行了研究,低温是日本结缕草(Zoysia japonica)冬季生长的主要限制因素。在田间条件下,探讨其对冷胁迫-2℃的生理响应。结果表明,在冷胁迫下,起源于N 35°地区的草坪质量(TQ)显著低于其他纬度地区;起源高纬度地区的日本结缕草丙二醛(MDA)含量较低,超氧化物歧化酶(SOD)和过氧化物酶(POD)活性最高,而起源低纬度地区的过氧化氢酶(CAT)活性最低;SOD和CAT活性与纬度之间呈正相关,而MDA含量与纬度呈负相关。高纬度地区日本结缕草游离脯氨酸(Pro)、可溶性糖(SS)和可溶性蛋白(SP)含量显著高于低纬度地区日本结缕草,并与纬度呈正相关。     

夏季猪的热应激及应对措施

<正>热应激是指处于极端高温环境中的动物机体对热环境所作的非特异性生理反应的总和。随着集约化高密度饲养方式的迅速发展,在我国南方的大部分地区,夏季和初秋气温高、湿度大,中北     

Positive Impact of Deficit Irrigation on Physiological Response and Fruit Yield in Citrus Orchards： Implications for Sustainable Water Savings

Different strategies of deficit irrigation based on water stress dynamics were applied in an 11-year old citrus trees （Citrus sinensis L. Osb. cv. Navelina） grafted on carrizo citrange （Citrus sinensis L. Osb.×Poncirus Trifoliata L. Osb.）. The trees were subjected to two irrigation treatments： （1） sustainable deficit irrigation （SDI） established with water supplied at 60% of the crop evapotranspiration （ETc） and （2） low frequency deficit irrigation （LFDI） irrigated according to the plant water status. In addition, a treatment irrigated at 100% of ETc was included as a control （C）. Midday stem-water potential （ψUstem）, stomatal conductance （gs）, and micrometric trunk diameter fluctuations were measured during the maximum evapotranspirative demand period to evaluate the plant-water status, and establish the main relationships among them. The seasonal pattern of the studied variables had a behavior consistent with the contributions made by the volumes of applied irrigation water. Especially significant close relationships of ψstem with gs, and with the maximum daily shrinkage （MDS） were found. The lowest ψstem and gs values were registered in the treatments with lowest irrigations levels （SDI and LFDI）, being the MDS was significative higher than in the C treatment. The LFDI showed an oscillating behavior in these parameters, which was on line with the supplied irrigation restrictions cycles. Thus, according to the results of the present experiment the physiological stress indexes based in MDS or ψstem allow establishing different irrigation restriction cycles, encouraging important water saving without significant impact on yield and the fruit quality parameters.     

紫花苜蓿种质耐盐性综合评价及盐胁迫下的生理反应

以中苜1号为对照,对来自俄罗斯的18份紫花苜蓿种质的耐盐性进行了综合评价,并对盐胁迫下的生理反应进行了初步研究。结果表明,运用标准差系数赋予权重法进行综合评价,不但考虑了不同指标的权重,还定量的鉴定出了每份材料的耐盐能力,比聚类分析的结果更具科学合理性,试验共筛选出M7、M9、M15、810共4份耐盐性强的种质;在此基础上,进一步探讨了盐胁迫下的生理反应,除叶水势随着盐浓度的增加呈下降趋势外,游离脯氨酸含量、可溶性糖含量、细胞质膜透性、丙二醛含量、水分饱和亏缺则呈上升趋势,且不同材料变化幅度不同。可溶性糖含量、细胞质膜透性、丙二醛含量、水分饱和亏缺和叶水势等指标很好的反映了材料间的耐盐性,可直接作为耐盐评价的鉴定指标。     

Human responses to flower fragrance of Lilium ‘Siberia’ and Rosa ‘Escimo’

The objective of our study was to lay a foundation for the effect of flower fragrance on human emotions and to provide a theory for the choice of indoor plants and the improvement of the olfactory environment. Specifically, our purpose was to study human physiological responses to flower fragrance of Lilium ‘Siberia’ and Rosa ‘Escimo’. The participants were 31 college students. Blood pressure, pulse rate, finger temperature (FT) and galvanic skin response (GSR) were measured. The results show that the fragrance of Rosa ‘Escimo’ causes the diastolic pressure and pulse rate of the participants to reduce significantly. The average decrease was 0.37 kPa and 2.23 beats per minute, which indicates that sympathetic nervous activity increases, physiological arousal decreases and emotional alleviation occurs. Furthermore, the GSR of participants significantly increased by smelling the fragrance of Lilium ‘Si-beria’, indicating that both sympathetic nervous activity and physiological arousal increased. But the data could not prove that flower fragrance stimulation has an effect on changes in systolic pressure and finger temperature. Some other factors, such as basic emotion and weather, may have an effect.     

以热降热--关于减轻肉鸡热应激的几项研究

热应激是多数鸡场都面临的一个主要问题。在气候炎热的地区，人们常常会低估热应激的后果。在温带地区，如果不采取预防措施，热应激会给鸡场带来严重损失。