UV—B辐射增强对植物光合作用的影响及植物的相关适应性研究

综述了UV－B辐射增强对植物光合作用的影响,植物对光破坏的响应与适应性方面的国内外研究进展,许多研究表明UV－B辐射增强对植物具有破坏作用能引起植物光抑制,光氧化和光损伤,植物依靠自身修复系统而对其破坏又具有一定的适应性。     

增强UV—B辐射对蚕豆叶片微粒体膜一些性质的影响

温室条件下,用０,８．６５ｋＪｍ＾－２ｄ＾－１及１１．２ｋＪｍ＾－２ｄ＾－１不同剂量的ＵＶ－Ｂ辐射处理蚕豆幼苗。Ｃａ＾２＋－ＡＴＰａｓｅ及Ｍｇ＾２＋－ＡＴＰａｓｅ的活性在辐射处理期间下降。在处理２１ｄ,Ｔ１和Ｔ２微粒体膜的ＭＤＡ含量明显高于对照,同时ＩＵＦＡ急剧下降,且呈明显的剂量效应。     

增强UV-B辐射与干旱复合处理对小麦幼苗生理特性的影响

为研究由于平流层臭氧层减薄紫外线B辐射增强在干旱地区对春小麦生理特性的影响的特殊性,模拟平流层臭氧减少20％时辐射到地表的紫外线B（UV－B,280－315nm)的增强和水分胁迫（－0.5Mpa,聚乙二醇PEG－6000处理获得）,通过测定两种胁迫下春小麦（Triticum aestivum L.)叶绿素含量、类黄酮含量、水势、细胞膜相对透性、超氧歧化酶（SOD）活性及丙二醛（MDA）含量,研究了增强UV－B辐射和水分胁迫复合作用对温室种植的小麦幼苗生理生化的影响。实验结果表明,虽然水分胁迫和UV－B辐射单独或复合处理都使春小麦的叶绿素含量降低,但仅UV－B辐射增强单独处理显著地降低小麦叶绿素a、b和总叶绿素的含量,而水分胁迫以及复合处理对叶绿素的含量的降低作用不显著。两种胁迫无论是单独作用还是复合作用均能使类黄酮含量升高,并且处理第3天比第1天高出近50％,复合处理下类黄酮的含量大于两个因子单独处理。UV－B辐射和水分胁迫处理1d对春小麦叶片的相对电导率的影响不明显,处理3d后两种胁迫下相对电导率均上升,表明膜透性增加,其中水分胁迫作用下增加尤其明显。膜质过氧化产物丙二醛的含量,在两种因子单独和复合作用下都升高,说明膜的生理功能受到了一定的不利影响。活性氧清除剂超氧化物歧化酶（SOD）的活性在各种处理下,都没有发生改变。虽然增强的UV－B辐射和干旱处理一样,会显著降低植物水势,但是,UV－B辐射与干旱同时处理时叶片水势降低的程度,不但没有比两者分别处理时降低程度之和低,而且比单做干旱处理时的降低程度还低,这表明UV－B辐射和干旱胁迫同时处理时,UV－B辐射不但没有加重水分胁迫,反而减轻了干旱对春小麦生长的胁迫。由此可以认为,在干旱条件下,增强UV－B辐射不会加剧而是有利于提高小麦对干旱的抗性。     

田间增加紫外线（UV）辐射对大豆幼苗生长和光合作用的影响

 两个增加的UV(UV-AB,280～400nm)辐射强度分别相当于大气臭氧减少3.6％和5.1％时增加的UV-B辐射。UV辐射增强明显降低大豆的株高、叶面积、干重、水分含量和叶绿素含量,大豆生长受抑程度随人工UV光源照射时间和强度增加而增强,是增加UV辐射剂量的累积效应,叶绿素b的降幅大于叶绿素a,表明UV辐射对大豆幼苗捕光色素的破坏较严重。同时,增加UV辐射还使大豆幼苗的表观光合速率、蒸腾速率、水分利用效率、气孔导度下降,作用效果与辐射强度正相关。与生长等比较,UV辐射条件下,冠／根比值减少幅度不大。分析认为,大豆幼苗生长和光合能力的下降可以使植物避免或减轻UV辐射的进一步伤害,对植物适应UV辐射有利。     

大豆作物响应增强UV—B辐射的品种差异

田间条件下模拟20％平流层臭氧层衰减,紫外线（UV－B,280－315nm)辐射增强,研究了UV－B对2个大豆（Glycin max (L.)Merr.)品种黑豆和晋豆生长,光合作用和稳定碳同位素组成的影响,结果表明,晋豆比黑豆对UV－B有较强的抗性或不敏感,表现为增强的UV－B辐射显著抑制黑豆的生长和株高,叶、茎、根和总生物量以及株高全部降低,而晋豆仅茎重和株高降低;晋豆的色素含量（叶绿素a,b,类胡萝卜素和类黄酮）不受UV－B辐射影响,在UV－B辐射下黑豆的净光合作用,气孔导度,胞间CO2浓度和蒸腾作用以及不分利用效率明显下降,而晋豆只有气孔导度和蒸腾作用减少,这可能与晋豆本身含有较高的类黄酮及较多的表皮毛和遗传特性有关,用叶片稳定碳同位素组成（δ^13C值）的分析也证明晋豆对UV－B辐射不敏感,由此看来,大豆品种对UV－B辐射的反应差异可以通过δ^13C值来判定。     

UV-B辐射对几种木本植物幼苗生长和叶绿体超微结构的影响

在实验室条件下研究了UV－B辐射对广东省南亚热带森林中5种木一植物九节,鸭脚木,猴耳环,半枫荷,山乌桕和绿化树种大叶合欢的幼苗形态和细胞超微结构。特别是叶绿体超微结构的影响。结果表明,UV－B辐射抑制幼苗主根伸长和减少侧根数,抑制茎伸长,减少叶数和叶面积。UV－B辐射破坏叶片细胞膜细胞,特别是叶绿体膜结构,但不同种受影响的程度不同,所表现的症状也不完全相同,鸭脚木的质膜收缩,导致质壁分离;鸭脚木,半枫荷和猴耳环的叶绿体膨胀,前二者的甚至破裂,鸭脚木的质膜收缩,导致质壁分离;鸭脚木,半枫荷和猴耳环的叶绿体膨胀,前二者的甚至破裂;鸭脚木和半枫荷的类囊体膨胀粘连;猴耳环的线粒体出现空泡化,半枫荷和猴耳环的叶绿体内大的淀粉粒增多;鸭脚木和山乌桕的叶绿体内或膜上黑色颗粒增多,鸭脚木的线粒体膜上也出现黑色颗粒。     

ＵＶ—Ｂ辐射对８个大豆品种种子萌发率和幼苗生长的影响

在生长房５种（暗处、可见光、低、中、高强度紫外线－Ｂ）处理下,研究了８个大豆品种的种子萌发率和萌发后幼苗的生长状况。结果表明,暗处种子萌发率高于自然当和ＵＶ－Ｂ辐射的种子。ＵＶ－Ｂ辐射增强对大豆种子的萌发率没有显著影响,仅使部分 品种的最大萌发率降低和导致部分品种达到最大萌发率的时间延长。幼苗的生长对增强的ＵＶ－Ｂ辐射非常敏感,使大部分品种的胚根变短增粗,这可能是植物激素作用的结果,大豆的叶绿素a、叶绿素b和总叶绿素含量明显受到ＵＶ－Ｂ辐射的抑制。ＵＶ－Ｂ作用能促进类黄酮在幼苗中的积累,紫外吸收色素的增设有利于提高对ＵＶ－Ｂ的抵抗力,ＵＶ－Ｂ辐射的这种效应及大豆种间的差异在自然情况下会产生深远的生物学和生态学意义。     

UV—B辐射对小麦叶片H2O2代谢的影响

研究了温室种植的小麦在０（ＣＫ）、８．８２ｋＪ／ｍ＾２（Ｔ１）和１２．６ｋＪ／ｍ＾２（Ｔ２）三种剂量的紫外线Ｂ（ＵＶ－Ｂ）辐射下Ｈ２Ｏ２含量的变化及其机理。ＵＶ－Ｂ辐射下Ｈ２Ｏ２、还原型抗坏血酸（ＡｓＡ）和还原型谷胱甘肽（ＧＳＨ）含量增加,抗坏血酸过氧化物酶（ＡＰｘ）和谷胱甘肽不原酶（ＧＲ）活性升高,脂肪酸不饱和度指数（ＩＵＦＡ）降低。ＳＤＳ－ＰＡＧＥ谱图没有质上的差异,但凝胶着色深浅有变化。分析     

增强UV—B辐射对高山植物麻花艽净光合速率的影响

在高寒矮嵩草（Kobresia humilis)草甸地区以太阳短波辐射为背景,建立了人工增强UV－B辐射的实验装置,每天增补15．8kJ.m^-2的辐射剂量,模拟平流层臭氧破坏约5％时近地表面太阳UV－B辐射的增强。观测表明：UV－B辐射的增强对麻花艽（Gentiana stramianea)植物的光合作用无明显的抑制或伤害作用。相反,在早晨补充UV－B辐射的短时间内,叶片的Pn随Gs的增大而有所提高。随着UV－B辐射时间的延长,在11：30－12：30,Pn和Gs有所降低。UV－B辐射时间进一步延长后（约14：00以后）,处理和对照组叶片Pn和Gs的差异趋向不明显,增强太阳UV－B辐射后,麻花艽叶片的光合色素并无明显变化,UV－B吸收物质的含量无明显变化,麻花艽叶片厚度的直接测量表明,增强UV－B辐射能明显提高叶片的厚度。叶片厚度的增加可补偿增强UV－B辐射辐后引起的光合色素的光降解,改善单位叶面积为基础的光合速率,是高原植物对强UV－B辐射的一种适应方式。     

高浓度CO2对极大螺旋藻生长和光合作用的影响

以极大螺旋藻作为实验材料,研究了高CO2浓度对极大螺旋藻的生长和光合作用效应,结果表明在高光强下（400μmolm^-2s^-1),高浓度CO2对其生长和光合作用有明显的影响。高浓度CO2培养下,辈放荡中的比生长速率是低浓度CO2培养的1.2倍;而在低光强下,高浓度CO2对其生长和光合作用无明显影响。两种不同CO2浓度和光强下培养的极大螺旋藻,在不同的生长时期,分别测定其P-I曲线,结果表明,低光强下培养的极大螺旋藻,在5d、8d、11d,两者的Ik、α值均无显著差异,Pmax在第5d、11d差异不显著,但在第8d有显著差异。而在高光强培养条件下,第8、11d通高浓度CO2培养的极大螺旋藻,其Pmax、α值明显大于通低浓度CO2培养的极大螺旋藻,但两者在第5d无明显差异。     

UV-B辐射对蚕豆叶膜脂过氧化的影响及其机制

温室种植的吞豆在0（CK）,8．82kJ/m2(T1)和12．6kJ/m2(T2)3种剂量的紫外线B（UV－B）辐射引起膜脂变化及其机制的研究结果表明,UV0B处理后,蚕豆叶片中丙二醛（MDA）和H2O2含量升高,膜脂肪酸不饱和度指数（IUFA）降低,脂氧合酶（LOX）活性升高,超氧歧化酶（SOD）活性稍有波动,而3种多胺－腐胺（Put)精胺（Spd)和尸胺（Spn)在照射7天后均有积累,但在处理后期（21d)有所回落,推测由LOX主导的酶促膜过氧化作用和氧自由基引起的非酶促过作用在膜结构的破坏中起重要作用,SOD活性和多胺含量的变化蚕豆对UV－B胁迫的一种适应性生理反应。     

Combined effects of CO2 concentration and enhanced UV-B radiation on faba bean

Due to anthropogenic influences, both solar UV-B irradiance at the earth's surface and atmospheric [CO₂] are increasing. To determine whether effects of CO₂ enrichment on faba bean (cv. Minica) growth are modified by UV-B radiation, the effects of enhanced [CO₂] on growth and photosynthetic characteristics, were studied at four UV-B levels. Faba bean was sensitive to enhanced UV-B radiation as indicated by decreases in total biomass production. Growth stimulation by CO₂ enrichment was greatly reduced at the highest UV-B level. [CO₂] by UV-B interactions on biomass accumulation were related to loss of apical dominance. Both [CO₂] and UV-B radiation affected biomass partitioning, UV-B effects being most pronounced. Effects of [CO₂] and UV-B on faba bean growth were time-dependent, indicating differential sensitivity of developmental stages. [CO₂] and UV-B effects on photosynthetic characteristics were rather small and restricted to the third week of treatment. CO₂ enrichment induced photosynthetic acclimation, while UV-B radiation decreased light-saturated photosynthetic rate. It is concluded that the reduction in biomass production cannot be explained by UV-B-induced effects on photosynthesis.     

The combined effects of CO2 concentration and solar UV-B radiation on faba bean grown in open-top chambers

The response of faba bean seedlings to the combined effects of increased atmospheric CO2 concentrations ([CO2]) and solar UV-B irradiance was studied using open-top chambers transparent to UV-B radiation. The purpose of the study was to determine whether effects of increased [CO2] on growth and physiology are modified by the present solar UV-B fluence rate in the Netherlands. Seedlings were exposed to 350 or 700 micromoles mol-1 CO2. At both [CO2], solar UV-B irradiance was either present or reduced using polyester foil opaque to UV-B radiation. To obtain information on the time dependence of increased [CO2] and UV-B radiation effects, three harvests were performed during the experiment. CO2 enrichment resulted in increased biomass production at all harvests. At the final harvest, UV-B radiation did not affect biomass production but a significant decrease was observed after 14 d of treatment. A reduction of the UV-B fluence increased shoot length at both [CO2] throughout the experiment. UV-B radiation slightly altered biomass allocation. Plants grown at reduced levels of UV-B radiation invested less biomass in flowers and more in stem material compared to plants grown at ambient UV-B levels. CO2 enrichment resulted in a stimulation of net photosynthesis after 26 and 38 d of treatment. UV-B reduction did not alter this response. After 26 d of treatment, photosynthetic acclimation to CO2 enrichment was observed, which was probably the result of accumulation of carbohydrates in the leaves. After 38 d, photosynthetic acclimation was no longer present. The UV absorbance of methanolic leaf extracts was increased by CO2 enrichment only. Both CO2 enrichment and solar UV-B reduced the transmittance of radiation through intact attached leaves. Interaction between [CO2] and UV-B radiation was limited to UV-A transmittance of leaves. Under prevalent experimental conditions, UV-B radiation did not affect the measured physiological parameters. Most open-top chambers used for climate change research are constructed of materials which do not transmit UV-B radiation. Our results indicate that part of the 'chamber effects' on plant height often described in the literature might be explained by the absence of solar UV-B radiation in these chambers.     

CO2浓度倍增减轻UV-B辐射对大棚番茄的抑制作用研究

在CO2浓度倍增(700 μmol·mol-1)条件下,以5个不同剂量的UV-B辐射对大棚番茄的光合作用及SOD、POD、CAT酶活性的影响进行了研究.结果表明CO2倍增能够明显提高番茄叶绿素含量、净光合速率和抗氧化酶活性.在CO2倍增条件下,低剂量UV-B辐射(<1.163 kJ·m-2·d-1)可以刺激番茄叶片叶绿素含量升高,抗氧化酶活性升高,与CO2的正效应有叠加现象,但对光合作用的影响不大;高剂量的UV-B(>1.163 kJ·m-2·d-1)辐射使植株的叶绿素含量、净光合速率和抗氧化酶活性降低,对植物产生胁迫作用,CO2倍增与UV-B辐射复合处理可以减弱和部分抵消这种抑制作用.     

Effects of UV-B radiation on photosynthesis and growth of terrestrial plants

The photosynthetic apparatus of some plant species appears to be well-protected from direct damage from UV-B radiation. Leaf optical properties of these species apparently minimizes exposure of sensitive targets to UV-B radiation. However, damage by UV-B radiation to Photosystem II and Rubisco has also been reported. Secondary effects of this damage may include reductions in photosynthetic capacity, RuBP regeneration and quantum yield. Furthermore, UV-B radiation may decrease the penetration of PAR, reduce photosynthetic and accessory pigments, impair stomatal function and alter canopy morphology, and thus indirectly retard photosynthetic carbon assimilation. Subsequently, UV-B radiation may limit productivity in many plant species. In addition to variability in sensitivity to UV-B radiation, the effects of UV-B radiation are further confounded by other environmental factors such as CO₂, temperature, light and water or nutrient availability. Therefore, we need a better understanding of the mechanisms of tolerance to UV-B radiation and of the interaction between UV-B and other environmental factors in order to adequately assess the probable consequences of a change in solar radiation.Abbreviations A_max light and CO₂ saturated rate of oxygen evolution - Ci internal CO₂ concentration - F_v/F_m ratio of variable to total fluorescence yield - PAR photosynthetically active radiation (400–700 nm) - PS II Photosystem II - _app apparent quantum yield of photosynthesis - SLW specific leaf weight - UV-B ultraviolet-B radiation between 290–320 nm     

UV－B辐射增强对长白山五种藓类植物生长的影响

对生长在中国长白山的5种藓类植物——垂枝藓、拟垂枝藓、塔藓、星塔藓和高山金发藓分别以辐射强度为0.2(自然光照,对照)、3.0(紫外线中等辐射强度)和6.0kJ.m-2.d-1(高剂量辐射强度)的UV-B照射40d后,测定其株高、生物量及叶绿素含量.结果表明:中等和高强度的UV-B辐射使拟垂枝藓和塔藓的株高、生物量和叶绿素含量分别下降了32.3%、62.4%、81.3%和21.4%、59.4%、62.8%,其相对生长速率均为负值;高剂量UV-B辐射处理下垂枝藓的生物量稍有上升,而高山金发藓地下部分的生物量增加1倍,但叶绿素含量变化不明显.高山金发藓和垂枝藓抵抗UV-B辐射的能力较强,拟垂枝藓和塔藓对UV-B辐射较敏感.     

UV-B辐射增强对NaCl胁迫下小麦幼苗生理生态的影响

研究了0.4w·m-2的紫外线-B(UV-B)辐射对0.8%NaCl胁迫下冬小麦"小偃926"(TriticumaestivumL.xiaoyan-926)幼苗的生长、光合作用、水分状况、黄酮含量和膜脂过氧化等几方面的影响。结果表明,UV-B辐射和NaCl胁迫单独或复合处理下小麦幼苗的株高、生物量、含水量、净光合速率、蒸腾速率、气孔导度和光合色素含量均显著降低,膜脂过氧化产物丙二醛含量和叶片相对电导率则升高,但NaCl胁迫条件下增加UV-B辐射(复合处理)与单独NaCl胁迫相比,上述指标多数均无显著差异(除复合处理下类胡萝卜素含量显著降低外)。两胁迫因子单独或复合处理均明显提高了小麦幼苗黄酮含量及三种抗氧化酶(SOD、POD和CAT)活性,且复合处理的促进效应最大。脯氨酸含量在单独UV-B辐射下明显降低,在单独NaCl胁迫和复合处理下显著升高,且复合处理下增幅最大。结果说明UV-B辐射不会明显加剧NaCl胁迫下小麦幼苗的伤害,这可能与NaCl胁迫提高了小麦幼苗黄酮含量、脯氨酸含量和抗氧化酶活性有关。     

Mixed cropping with maize combined with moderate UV-B radiations lead to enhanced flavonoid production and root growth in faba bean

Abstract

Flavonoids have recently been proposed to function as developmental regulators and/or signaling molecules under biotic or abiotic stress. The aim of this study was to determine the composition and concentration of fiavonoid aglycones (kaempferol, luteolin, and quercetin) in faba bean shoots and roots, as affected by interspecific root interactions with maize and moderate UV-B radiation. Independent of the UV-B treatment, interspecific root interactions with maize enhanced the concentration of both quercetin and luteolin in the faba bean shoots and roots by 50 and 97.8%, respectively, and improved the root length by 14.6%. In addition, moderate UV-B radiation facilitated a systematic increase of both aglycones in both shoots and roots without affecting plant growth. To our knowledge, this report is the first work documenting the response of faba bean flavonoids to interspecific root interactions with maize and moderate UV-B radiation, and it provides a new perspective for understanding interspecific interactions.