UV-B辐射对植物类黄酮影响的研究进展

UV-B辐射增强对农业生态系统和作物产量的影响已引起国内外广泛关注。本文结合近年来国内外研究成果,介绍了UV-B辐射胁迫下植物应激合成与累积类黄酮的特征,考察了类黄酮在抵御UV-B辐射胁迫中的生态生理作用及其机理,探讨了类黄酮与其他抗UV-B辐射机制的关系,分析了未来该研究工作的若干取向。     

紫外辐射与复合胁迫对植物抗氧化酶系统的影响

植物抗氧化酶系统对UV-B辐射增强与复合胁迫的响应是植物抵御逆境伤害的关键机制之一。结合近年来国内外研究成果,概述了UV-B辐射对植物抗氧化酶基因表达、转录与翻译的影响,植物抗氧化酶系统对UV-B辐射与干旱、臭氧、高温、盐渍、重金属及酸雨复合胁迫的响应,以及CO2、抗坏血酸、α-萘乙酸、硒、激光辐射和稀土等调节因子对UV-B辐射下植物抗氧化酶系统的作用。     

UV-B辐射对植物水分代谢的影响

为系统了解UV-B辐射对植物水分代谢的影响, 本文从生理、生化两个角度概述了近30年国内外相关方面的研究成果, 内容涉及UV-B辐射对植物根系活力、蒸腾速率、水分利用效率及植物不同发育期叶片脯氨酸、可溶性糖含量的影响;总结了UV-B辐射对植物气孔行为的影响及相关机理, 包括植物体内ABA、H2O2、NO等信号分子含量的变化以及这些信号分子在调节气孔行为方面发挥的作用。认为UV-B辐射对植物水分 代谢产生伤害, 且此伤害作用与植物种类、发育阶段有关, 与UV-B辐照时间及剂量正相关。研究UV-B辐射对植物水分代谢的影响, 对自然及农业生产环境下规避UV-B辐射对植物产生逆境胁迫效应具有积极的环境生态学价值。     

UV-B辐射对植物水分代谢的影响

为系统了解UV-B辐射对植物水分代谢的影响, 本文从生理、生化两个角度概述了近30年国内外相关方面的研究成果, 内容涉及UV-B辐射对植物根系活力、蒸腾速率、水分利用效率及植物不同发育期叶片脯氨酸、可溶性糖含量的影响;总结了UV-B辐射对植物气孔行为的影响及相关机理, 包括植物体内ABA、H2O2、NO等信号分子含量的变化以及这些信号分子在调节气孔行为方面发挥的作用.认为UV-B辐射对植物水分代谢产生伤害, 且此伤害作用与植物种类、发育阶段有关, 与UV-B辐照时间及剂量正相关.研究UV-B辐射对植物水分代谢的影响, 对自然及农业生产环境下规避UV-B辐射对植物产生逆境胁迫效应具有积极的环境生态学价值.     

水稻对UV-B辐射增强的生理响应及其分子机制研究

本文以水稻为研究对象,从细胞、个体和群体水平系统分析了不同水稻品种对UV-B辐射增强差异响应的遗传生理与防卫机制。试从农业生态系统角度,结合作者近期研究成果,系统分析了近年来国内外的研究重点及其成就。已有研究认为水稻对UV-B辐射增强的生理响应存在明显的种间差异,通常认为起源于靠近赤道附近的低纬度地区的籼稻品种比高纬度地区的粳稻品种更抗(耐)UV-B辐射污染,但许多研究结果不支持这一假说,即在籼粳稻品种中均存在明显对UV-B辐射增强呈不同抗性的种质资源。进一步研究结果表明水稻对UV-B辐射的响应差异是可遗传的数量性状。QTL定位分析结果发现多数抗UV-B辐射相关性状的加性QTL主要集中在第1、2、3、6染色体上,并检测到一些加性QTL还存在加性×加性上位性及其与环境的显著互作效应。作者还深入分析了水稻抗UV-B辐射增强的分子生理与调控机制,提出适当增加植物的硅营养,可以有效提高其抗逆性。最后,作者提出从农田生态系统角度研究和评价UV-B辐射增强所带来的生态风险及其影响是今后研究的重点,强调应重视研究田间条件下UV-B辐射增强及其与其他生态环境因子的互作对作物生长发育的综合影响,在此基础上,探索建立作物遗传改良与栽培调控的减灾防灾技术,为应对全球环境变化,制订相关防护策略提供理论依据和技术支撑。     

作物防御UV-B辐射伤害的机理

自上世纪80年代中期发现南极"臭氧洞"及平流臭氧层耗竭现象以来,有关UV-B影响生物和生态系统的研究逐渐成为气候变化研究关注的热点之一。过去40年里,针对UV-B增加对作物的潜在影响,研究者们展开了大量深入细致的研究。研究发现,自然和增强的UV-B降低作物产量的幅度一般不会超过20%,这种有限的产量损失反映了作物自身特有的防御UV-B损伤的机制。本文从植(作)物对UV-B辐射增强表现的4个层次,即植物形态、生理、生物化学和分子水平变化的光形态建成和胁迫响应,对作物防御UV-B辐射伤害的可能机制予以综述,并提出了今后需要注重研究的几个方向,旨为抗UV-B育种和农艺措施制定提供具有现实价值的信息和理论依据。     

Ce对UV- B胁迫下油菜幼苗光合与保护酶的影响

UV—B辐射增强对植物生理、生化和生长发育的影响，国内外已有大量报道，这为科学评价UV—B环境植物学效应奠定了基础。与此交臂的是，稀土（RE）用于酸雨、重金属、臭氧及农药污染防治等方面的工作也已初见端倪。本文初步考察了RE对UV—B辐射胁迫下植物光合与保护酶功能的影响，旨在为RE农用拓展及环境污染防治提供依据。     

UV-B辐射的增强对作物形态及生理功能的影响

通过综述UV-B辐射增强对作物产生的影响,为进一步揭示作物对UV-B辐射增强的响应机制、适应变化和寻找相应的解决方法提供参考.分析发现UV-B辐射增强能对作物的形态在根、茎、叶营养器官和生殖器官方面产生负面影响,从而进一步影响作物的生物量和产量;UV-B辐射增强对植物生理的影响主要通过影响作物的叶绿体、光合作用及矿质代谢而起作用,并且这些影响具有品种间和生育期的差异.因此研究紫外辐射对作物的影响具有重要的生态学意义.     

Ce(Ⅲ)对UV-B胁迫下大豆幼苗光呼吸的影响

采用水培法研究Ce(Ⅲ)对紫外辐射(UV-B0.15Wm-2,0.45Wm-2)胁迫下大豆(Glycine max)幼苗光呼吸速率(Pr)、光合速率(Pn)和叶绿素(Chl)含量的影响.实验结果表明与CK相比,元UV-B胁迫时20mg·L-1CeCl3能够有效提高Pr和Pn;UV-B处理使Pn与Chl含量降低,Pr增加;Ce UV-B组的Pr、Pn和Chl含量曲线走势均高于UV-B组.通过对Pr、Pn和Chl含量3项指标研究表明,20mg·L-1CeCl3能提高UV-B胁迫下大豆幼苗的Pr、Pn和Chl含量,通过提高Pr可消耗过多的光能,减轻UV-B辐射对大豆幼苗光合器官的伤害.抑制UV-B辐射胁迫下大豆幼苗Pn的下降,缓解Chl的降解,增强植物的抗逆性.     

高压电场对毛乌素沙地两种优势植物抗旱性的影响

以毛乌素沙地优势植物柠条(Caraganaintermedia)和沙蒿(Artemisiasongaricaschrenk)种子为对象,采用人工模拟干旱试验方法,研究不同电场处理后这2种植物种子萌发和生物量对土壤干旱胁迫的响应。结果表明,电场处理缓解了2种植物随干旱程度加重出现的负效应,不同处理条件,种子萌发和生物量对干旱胁迫的适应性的影响不同,电场处理能够提高种子在干旱胁迫条件下的发芽率和发芽势,提高2种沙生植物生物量干重和鲜重。这些变化缓解了干旱胁迫对柠条和沙蒿种子的伤害,提高了其对干旱胁迫的适应性。     

UV-B辐射增强对大麦生理生态的影响

在大田条件下,研究了UV-B辐射增强对大麦的生长发育、光合作用、蒸腾作用及其产量构成的影响。结果表明,UV-B辐射增强明显抑制大麦生长,使株高变矮、绿叶数减少、叶面积和干物质量下降,但抑制程度随生育期而异。在UV-B辐射增强条件下,大麦叶片叶绿素含量、净光合速率、气孔导度和蒸腾速率都有不同程度的降低,水分利用率也随之降低。UV-B辐射增强对大麦形态学和生理学上的不利影响,导致了大麦产量下降24.96%。     

Responses in Some Growth and Mineral Elements of Mono Maple Seedlings to Enhanced Ultraviolet-B and to Nitrogen Supply

The effects of enhanced ultraviolet-B (UV-B) and nitrogen supply on the growth and mineral elements of mono maple (Acer mono Maxim) seedlings were studied in open semi-field conditions. Mono maple is a common species in reforestation processes in the southeast of the Qinhai-Tibetan Plateau of China. The experimental design included two levels of UV-B treatments (ambient UV-B, 11.02 KJ/m²/day; enhanced UV-B, 14.33 KJ/m²/day) and two nitrogen levels (0; 20 g N/m²/a). No visible symptoms of nutrient deficiency were observed in seedlings grown under enhanced UV-B radiation during the experiment. However, there was visible damage of enhanced UV-B radiation on leaves. Enhanced UV-B significantly reduced plant height and biomass of plants, and changed biomass allocation between organs under supplemental nitrogen supply, which lead to a decrease in root/shoot ratio. On the other hand, nitrogen supply significantly increased plant height and biomass under ambient UV-B, whereas it reduced root mass and root weight ratio, and increased stem mass and stem weight ratio under enhanced UV-B. In addition, enhanced UV-B radiation and nitrogen supply significantly affected the concentration and allocation of most nutrients in various organs, and nitrogen supply could changed the effects of enhanced UV-B on mineral element in plant parts to some extent, which may have significant impacts on nutrient cycling and may lead to the disorder of nutrient balanced and influence the growth of plants.     

Field crop responses to ultraviolet-B radiation: a review

This paper provides an overview of existing literature on the ultraviolet-B (UV-B) radiation effects on field crops. Earlier reviews on field crop responses to UV-B considered few physiological processes or crops. For this review, we easily located about 129 studies on 35 crop species published since 1975. Here, we report the effects of UV-B radiation on visual symptoms, leaf ultrastructure and anatomy, photosynthetic pigments, UV-B absorbing compounds, photosynthesis, growth and development, yield, genotypic differences, and finally, interactions of UV-B with abiotic and biotic factors of crop plants. Experiments conducted in glasshouses, in closed and open top chambers, and under field conditions, with varying source (solar or artificial) and intensity of photosynthetically active radiation (PAR, 50–1800 μmol m⁻² s⁻¹) and UV-B (0–50 kJ m⁻² per day) are included. It is easy to conduct experiments that purport to evaluate the effects of projected UV-B intensities on crop species by providing supplemental irradiance with lamps or by reducing UV-B with filters; however, it is very difficult to simulate UV-B irradiance spectral changes that are likely to occur in nature. Collated results for each process are presented as percent change from control along with the experimental conditions in tabular format. Many of the studies showed dramatic effects of UV-B radiation, but under conditions with supplemental UV-B irradiance that was higher than would ever occur outside experimental conditions or in which the longer wavelengths in the PAR and UV-A, which moderate UV-B effects, were greatly reduced. Only 25 of the studies reviewed used experimental conditions and supplemental UV-B irradiance that approached realism. However, unrealistic the experimental conditions might be, an increase in understanding of basic plant physiology was gained from most of the studies.Visual symptoms consisting of chlorotic or necrotic patches on leaves exposed to UV-B were not unique. Both vegetative and reproductive morphology were altered by UV-B radiation. Leaf anatomy was altered due to changes in thickness of epidermal, palisade, and mesophyll layers. Enhanced UV-B generally decreased chlorophyll content (10–70%), whereas it increased UV-B absorbing compounds (10–300%) in many crops. Decrease in photosynthesis (3–90%), particularly at higher UV-B doses, was due to both direct (effect on photosystem) and indirect (decrease in pigments and leaf area) effects. The decreases in chlorophyll pigments and photosynthesis resulted in lower biomass and yield of most crop plants. Genotypes of crop species exhibited variability in leaf wax layer thickness, loss of chlorophyll, and increase in phenolics as mechanisms of tolerance to enhanced UV-B radiation resulting in changes in biomass/yield. Results from the few studies on interaction of UV-B with other abiotic and biotic factors did not lead to useful conclusions. Studies are needed to quantify the effects of UV-B radiation on crops in order to develop dose response functions that can facilitate development of dynamic simulation models for use in UV-B and other environmental impact assessments.     

UV-B辐射增强对葡萄光合作用日变化的影响(简报)

大气臭氧层的不断破坏引起了地球表面紫外线-B(UV-B）辐射强度不断增加,这对植物的生长发育产生了重要影响。试验以酿酒葡萄（V.vinifera. L）“赤霞珠”（Cabernet Sauvignon）为材料,在自然光照条件下,通过增加不同强度的UV-B辐射,研究UV-B辐射增强对葡萄叶片光合作用日变化的影响,为进一步研究UV-B辐射增强对植物的影响提供依据。结果表明,UV-B辐射增强后葡萄叶片净光合速率（Pn）、气孔导度（Gs）、胞间CO2浓度（Ci）、蒸腾速率（Tr）均呈双峰型,且日变化平均值表现为低辐射（T₁,10.8 μW/cm²）处理组＞对照组（CK）＞高辐射（T₂,25.6 μW/cm²）处理组,而水分利用效率则表现为对照组（CK）＞低辐射（T₁,10.8 μW/cm2）处理组＞高辐射（T₂,25.6 μW/cm2）处理的变化趋势。同时,UV-B辐射增强对葡萄叶片中光合色素含量没有显著的影响。这说明UV-B辐射增强对葡萄光合作用的影响与UV-B辐射强度和照射时间有关,适当增加一定剂量的UV-B辐射对葡萄光合作用不会造成危害。     

全生育期UV-B辐射增强对棉花生长及光合作用的影响

植物光合系统是UV-B辐射最初和最重要的作用靶标。本文在大田条件下进行紫外灯照射处理,研究全生育期UV-B辐射增强(高于环境20%和40%)对棉花形态、干物质积累、光合色素和产量的影响,并通过分析棉花主茎功能叶片的气体交换参数和叶绿素荧光参数,探讨UV-B辐射增强影响棉花光合作用的机制。结果表明,UV-B辐射增强抑制了棉花生长和干物质积累,籽棉产量显著降低,且UV-B辐射越强,抑制作用越明显。随UV-B辐射的增强,棉花主茎功能叶的净光合速率(P_n)在各生育期均显著降低,叶绿素含量呈先升高后降低趋势,气孔导度(Gs)和蒸腾速率(Tr)未发生变化,胞间CO_2浓度(Ci)反而升高,说明P_n下降主要由非气孔限制因素造成。对叶绿素荧光参数的分析表明,PSⅡ的最大光化学量子产率(F_v/F_m)、实际光化学量子效率(ΦPSII)、线性电子传递速率(ETR)和光化学淬灭系数(qP)随着UV-B辐射的增强而降低,非光化学猝灭系数(NPQ)则显著升高,且各叶绿素荧光参数与Pn变化均显著相关;慢速弛豫NPQ(NPQS)及其在NPQ中的比例均随UV-B辐射的增强而显著提高,表明PSⅡ反应中心受损,光化学效率降低。以上结果证明,全生育期UV-B辐射增强降低了棉花的光合叶面积、叶绿素含量和净光合速率,引起棉花生长与物质积累受抑,产量降低。UV-B辐射增强引起的光合速率下降与PSⅡ反应中心遭到破坏密切相关。     

锗对植物影响的研究进展

锗是良好的半导体材料,且具有清除自由基、抗衰老抗氧化等生物活性,在电子工业和医学领域应用广泛。目前在植物上的研究主要集中在提高植物品质,促进植物生长及对植物毒害等方面。本文综述了锗及其化合物的理化性质、起源与分布特征,分析了锗在影响植物生长方面的生理生化机制。锗具有清除自由基的电子结构,能改变土壤中酶活性和微生物,改变植物对营养元素的吸收和利用、影响植物光合作用、改变植物的抗氧化系统等。适宜剂量的锗能促进种子萌发,有效控制藻类生长,提高作物的品质。锗积累过多,影响生理代谢,抑制植物生长,产生毒害。锗在种子萌发、植物生长方面的研究与应用,为探索锗在调节植物生长、生理生态等方面的作用提供理论基础,为植物吸收利用锗,减少锗污染方面提供理论参考。     

Long-term acclimation of mesophyll conductance, carbon isotope discrimination and growth in two contrasting Picea asperata populations exposed to drought and enhanced UV-B radiation for three years

Two Picea asperata Mast. populations originating from wet and dry climate regions of China were subjected to enhanced UV-B radiation, drought and their combination in a greenhouse for 3 years. Drought treatment caused a significant decrease in photosynthesis, mesophyll conductance (g_m), carbon isotope discrimination (Δ) and growth characteristics when compared with well-watered treatment. In contrast to the great effects of drought stress, enhanced UV-B radiation showed some but not as substantial negative effects on these parameters. Little interaction effect between drought and UV-B radiation was detected, and the drought effect in combination with enhanced UV-B was not more pronounced than with no enhanced UV-B radiation. These results suggest that enhanced UV-B radiation does not aggravate the drought effect on P. asperata seedlings. The results also showed that the proportional role of the intercellular CO₂ (C_i) decreased, while the role of chloroplastic concentration (C_c) became increasingly important in explaining the high values of carbon isotope composition (δ¹³C), when the water stress progressed in time. In addition, multivariate causal models proposed that there is a direct causal relationship between specific leaf area (SLA) and g_m, which is not mediated by leaf N. Besides, there are functional links between g_m and photosynthetic capacity (V_cmax). On the other hand, the study showed that net assimilation rate (NAR) is the main driving force for changes in relative growth rate (RGR), especially in low-water environments, and the degree of acclimation of respiration in the light (R_L) is of central importance to the greater role played by NAR in determining variation in RGR.