增强的UV-B辐射对植物影响的研究

综述了国内外有关UV－B辐射对植物影响的研究现状与动态,讨论了增强的UV－B辐射对植物生长及形态结构、植物生理生化代谢、植物遗传物质、UV－B吸收物质及某些基因表达和种群及生态系统的影响。展望了增强的UV－B辐射对植物影响领域中值得深入探讨的问题。     

增强的UV—B辐射对麦田生态系统Mg和Zn累积和循环的影响

近 2 0多年以来 ,ＵＶ Ｂ辐射增加对植物个体的影响受到了广泛的关注 ,而对植物群体和生态系统的影响仍然知道的很少[2 ] 。仅见ＵＶ Ｂ辐射对副极地石南灌丛和沙丘草地生态系统物种结构、生长、物候和叶分解等方面有报道[3,4 ] 。ＵＶ Ｂ辐射影响植物Ｍｇ和Ｚｎ吸收和运转[5～ 7] ,但对营养累积和物质循环的影响了解甚少[3] 。因此 ,大田条件下 ,植物群体和生态系统水平的营养累积和物质循环对ＵＶ Ｂ辐射的响应与反馈的研究 ,对于真实评估ＵＶ Ｂ辐射对生态系统的影响是必不可少的[2 ] 。ＵＶ Ｂ辐射对春小麦生长、生理、群体结构、植物营…     

大气污染对城市植被的生态胁迫效应综述

快速的城市化进程使得城市大气污染日趋严重,造成了城市植被的退化及其生态服务功能的下降.大气中的O_3、紫外(UV-B)辐射、重金属、SO_2等污染物及其复合污染从分子、细胞、个体、种群、群落和生态系统各个水平上都对城市植被造成了胁迫效应.本文从微观实验法和宏观高光谱遥感法两方面对已有的研究方法进行了分析和总结后,提出了以下几个今后需要关注的研究领域:开展野外和长期胁迫实验、植物受胁迫机理及多种因子复合胁迫研究等;同时指出应重视建筑物在城市大气污染生态胁迫中的重要作用,并在今后加强城市行道树相关方面的研究.     

紫外辐射对水生生物的影响研究进展

紫外辐射对陆生植物的生物学效应已被广泛研究,对水生生物也能产生一系列影响。本文在综述国内外紫外线在水体中渗透状况及影响因素的基础上,阐述了紫外辐射对浮游细菌和微型浮游生物、浮游植物、浮游动物、大型藻类、鱼卵和幼鱼、鱼类及两栖动物的生物学效应,从直接效应和间接效应两方面介绍了紫外辐射对水生生物作用的机理。未来研究应该注重紫外辐射与气候变化、酸沉降、水污染等环境因子联合作用对水生有机体产生影响,其研究对象应扩展至沉水植物、底栖生物等大部分水生有机体,这些研究将对深入研究水生生态系统的演化、水生生态系统退化及其修复起重要作用。     

田间增强UV—B辐射对麦田生态系统K营养和累积的影响

研究大田栽培和自然光条件下,模拟UV－B辐射（UV－B,280－315nm)增强对麦田生态系统K营养和累积的影响,UV－B辐射显著影响春小麦不同生育期各部位K含量和群体K累积,并显著降低群体K总累积,在5．31kJ.m^-2UV-B辐射下,春小麦群体K总累积的降低最显著,UV－B辐射降低春小麦群体K输出,标志着麦田生态系统K产投比降低,K循环功能下降,麦田土壤速效K含量增加是春小麦群体K输出降低的结果,并将导致土壤库中K储量的增加。     

UV-B辐射对植物花粉萌发率和花粉管生长的累积效应

研究了19种植物花粉在不同UV－B辐射强度和辐照时间下其萌发率和花粉管伸长的变化,结果表明,UV－B辐射增加显著抑制大多数植物花粉的萌发率和花粉管生长;与对照相比,较高强度的UV－B对花粉的抑制作用大于较低强度;几个种的花粉萌发率及花粉管生长对UV－B增强不敏感,甚至被UV－B辐射所促进;辐射时间越长,对花粉抑制作用愈大,说明具有辐射累积效应,由此可知,植物花粉的萌发过程对UV－B的敏感性变化在自然条件下将会产生严重的生态学后果。     

第42次植物与温度专题学术讨论会简介

1987年9月由英国实验生物学会环境生理组主办的第42次植物与温度专题学术讨论会在英国的Essex大学举行。这次会议的主要内容是回顾和综述有关温度对植物生态分布的影响以及温度效应的分子基础,共分植物群体水平上的温度(Temperature at the plant community level.)植物水平上的温度(Temperature atthe plant level.).细胞水平上的温度(Temperature at the cell level.)三个部分。     

干旱半干旱草地生态系统与土壤水分关系研究进展

研究干旱半干旱草地生态系统与土壤水分关系和相互作用机理对于揭示草地生态系统稳定性及其水土关键要素的变化过程具有重要意义。从不同界面、不同尺度综述了草地生态系统对土壤水分的影响及草地生态系统的响应与适应机制,总结了草地生态系统与土壤水分关系模型研究的相关进展,并分析了气候变化对草地生态系统和土壤水分关系的影响。草地生态系统通过影响水文过程和生态过程来影响土壤水分,土壤水分在植物生长发育、形态、生理生态过程、种间关系、群落组成和结构以及草地生态系统功能等方面对草地生态系统产生影响;充分揭示草地生态系统-土壤水分相互作用机理是模型研究的关键;气候变化对草地生态系统植物与土壤水分关系具有重要影响。今后应加强以下研究:1)开展草地不同优势种和植物功能型与土壤水分关系的研究,找出能反映植物对土壤水分响应的性状指标,阈值响应点及适应机制;2)注重对不同时间和空间尺度上的转换和比较;3)加强个体、群体和生态系统尺度草地植物生长模型的研究及其与土壤-植被-大气水分传输模型的耦合;4)加强草地生态系统与土壤水分关系对气候变化响应的研究。     

大气CO2浓度和温度升高对水稻叶片及群体光合作用的影响

大气ＣＯ２浓度升高对植物光合作用的影响研究多集中在单叶水平,在高ＣＯ２及高温下对植物单叶及群体光合进行比较的研究少有报道,而群体水平的研究则是预测生态系统反应所不可缺少的。采用田间开顶式培养室研究了大气ＣＯ２浓度和温度升高对水稻（ＯｒｙｚａｓａｔｉｖａＬ．）叶片及群体光合作用的影响。发现ＣＯ２浓度和温度对水稻叶片光合作用有协同促进作用,而对群体光合作用的促进则随时间的推移而减弱;单叶光合受到的促进作用大于群体光合;叶面积指数只在营养生长期受到促进,冠层叶片含氮量受ＣＯ２影响降低。群体呼吸（包括茎杆）增加及冠层叶片早衰可能是后期ＣＯ２对群体光合促进作用下降的原因。     

增强的UV—B辐射对麦田生态系统能量累积和流动的影响

研究了大田栽培和自然光条件下 ,模拟 UV- B辐射 ( UV- B,2 80～ 31 5nm)增强对麦田生态系统能量累积和流动的影响。在 5.31 k J· m- 2 UV- B辐射下 ,春小麦群体不同生育期叶、茎、根、穗、粒生物量和总生物量显著降低 ,各部位热值没有显著变化 ,各部位能量累积和总能量累积显著降低。能量累积与生物量呈极显著正相关 ,而与热值没有显著的相关性 ,可能生物量比热值对能量累积的贡献更大。 UV- B辐射显著降低春小麦群体能量输出 ,可能导致麦田生态系统能量流动功能下降。     

VARIATION IN UV-B SENSITIVITY IN PLANTS FROM A 3,000-m ELEVATIONAL GRADIENT IN HAWAII

Interest in the potential consequences of stratospheric ozone depletion has led to numerous studies that have evaluated the effects of ultraviolet-B (UV-B) radiation on plant growth and productivity. However, few studies have been conducted on plants from natural ecosystems. Differences in solar UV-B radiation along latitudinal or elevational gradients may have resulted in plants from diverse habitats developing contrasting sensitivities to UV-B radiation. In this study, seeds were collected along a 3,000-m elevational gradient in Hawaii and then germinated and grown in an unshaded greenhouse with either no UV-B radiation or one of two daily UV-B irradiances, 15.5 or 23.1 kj m². Seedlings were grown for 12 weeks and harvested to determine whether UV-B radiation altered plant biomass. The responses to UV-B radiation varied among species, but, in general, sensitivity to UV-B radiation was reduced as the elevation of seed collection increased. Of the 33 species tested, UV-B radiation significantly reduced plant height in 14 species and biomass in eight species. Biomass increased in four species grown under UV-B radiation. This study provides clear evidence that natural plant populations exhibit wide variation in UV-B radiation sensitivity and that this variation is related to the natural (ambient) UV-B radiation environment in which these plants grow.     

The effects of ultraviolet-B radiation on loblolly pine

Summary Depletion of stratospheric ozone and the resulting increase in ultraviolet-B (UV-B) radiation may negatively impact the productivity of terrestrial ecosystems. This concern has led to a number of studies that report the influence of supplementing UV-B radiation on plant growth and development. However, only two of these field studies have included tree species and both were singleseason experiments. In this study, loblolly pine (Pinus taeda L.) from seven seed sources was grown under natural and supplemental levels of UV-B radiation. Irradiation treatments were continued for three seasons on plants from four of the seven groups and for 1 year only for three groups. The supplemental irradiances simulated those that would be anticipated with stratospheric ozone reductions of 16% and 25% over Beltsville, Md. The effects of UV-B radiation during the 1st year on plant growth varied among the seed sources. The growth of plants from two of the seven seed sources tested showed significant reductions following a single irradiation season and plants from one group tended to be larger under increased UV-B radiation. However, after 3 years of supplemental irradiation, plant biomass was reduced in all four groups by 12–20% at the highest simulated ozone depletion. These results suggest that the effects of UV-B radiation may accumulate in trees and that increased UV-B radiation could significantly reduce the growth of loblolly pine over its lifetime. However, they also point to a need for multiple season research in any analysis of potential consequences of global change on the long-term growth of trees.     

增强UV-B辐射及氮水平对长春花生长和生理代谢的影响

地表UV-B 辐射增强和氮沉降增加目前已成为影响植物生长的重要生态因子。本文以药用植物长春花（Catharanthus roseus）为材料,研究UV-B辐射和氮供应增加对长春花生长、生理及长春碱含量的协同效应。研究结果表明,紫外辐射增加对长春花生长和生物量积累具有显著的抑制作用。同时外源增加氮供应能明显缓解紫外辐射引起的生长抑制效应。紫外辐射引起的叶片膜脂过氧化胁迫导致了长春花叶片丙二醛含量显著增加,但同时增加氮供应能显著降低丙二醛水平。增强UV-B辐射处理显著促进长春花叶片UV-B吸收化合物合成积累,并随氮供应增加其含量进一步增加;氮供应增加和UV-B辐射增强共同作用时,长春花叶片中长春碱的含量较其单独作用时均显著增加。上述结果表明,增加氮供应不但可以缓解紫外辐射引起的生长抑制和生理伤害,同时对长春花叶片中生物碱的合成积累具有协同促进效应,其原因可能是增强UV-B辐射能促使长春花利用更多的氮源合成积累长春碱。     

UV-B辐射对马尾松凋落叶分解和养分释放的影响

由大气臭氧层减薄导致的UV-B辐射变化将直接影响到凋落物的分解。目前,有关UV-B辐射影响木本植物凋落物分解的研究还很少,在国内还没有开展。采用分解袋法开展了马尾松凋落叶在自然环境和UV-B辐射滤减两种辐射环境下的分解试验。结果表明：在UV-B辐射滤减环境下的马尾松凋落叶年分解速率比对照环境减慢了47.74%。UV-B辐射极显著(p<0.01)地加快了马尾松凋落叶的分解速率,促进了凋落叶中碳、磷、钾的释放和木质素的降解,对氮的释放无明显影响。研究结果意味着UV-B辐射将加快马尾松林的营养循环速度,降低马尾松林凋落物层的碳储量。     

Modulated increased UV-B radiation affects crop growth and grain yield and quality of maize in the field

Current research on the effect of increased UV-B radiation on crop production has been limited to exposing plants to improbable UV-B dose or growth condition. The objective of this study was to test the effects of short-term modulated increased UV-B radiation on maize (Zea mays L.) growth, grain yield, and quality under field conditions for three years. A modulated irradiance system was used to maintain UV-B radiation at 30% above the ambient level and was applied daily between the elongation and silking stages of maize. The result indicated that increased UV-B radiation adversely affected maize growth and yield, especially on plant height when UV-B was enhanced at the elongation stage and on yield when UV-B was enhanced near the silking stage. Yield reduction that induced by enhanced UV-B radiation was associated with reductions in number of kernels per row and kernel mass. Protein content of grains was increased with enhanced UV-B radiation, but oil and starch contents were not affected. This study confirmed the sensitivity of maize to increased UV-B radiation under the field condition, and contributed to understand the full negative and positive effects of increased UV-B radiation on crop production.     

The impacts of increased nitrate supply on Catharanthus roseus growth and alkaloid accumulations under ultraviolet-B stress

It has been reported that nitrate availability was able to modify the detrimental effects induced by excess ultraviolet-B (UV-B) radiation on plants. In this study, the medical plant Catharanthus roseus was subjected to UV-B stress and altered levels of nitrate nutrition to investigate their influence in a sole or combined way on growth and alkaloid productions. Our results showed that the UV-B stress obviously inhibited growth and led to damages of oxidative stress and lipid peroxidation. The simultaneous supply of higher nitrate nutrition could largely alleviate the inhibitory effects and damage symptom under the UV-B stress in C. roseus. Meanwhile, the UV-B-absorbing compounds as well as three alkaloids, vinblastine, vindoline, and catharanthine, were observed to have a remarkable elevation. These compounds were considered to serve as protectants of UV-B radiation. It was concluded that an increased nitrogen (N) supply could not only alleviate the inhibitory effect of UV-B stress on plant growth, but also enhance the accumulation of pharmaceutically used alkaloid in these plants. We proposed that the enrichment of N nutrition might provide more N source for alkaloid synthesis induced by UV-B radiation, eventually resulting in an increase of alkaloids accumulation.     

Effects of enhanced UV-B radiation on plant physiology and growth on the Tibetan Plateau: a meta-analysis

Uncertainties about the response of plant physiology and growth to enhanced UV-B radiation cause uncertainty to predict how plant production will vary under future radiation change on the Tibetan Plateau. Here, we used a meta-analysis approach to test the influence of UV-B radiation on plant physiology and growth. This hypothesis was tested by investigating the response of plants, which was expressed by some measurable variables. Enhanced UV-B radiation decreased plant biomass, plant height, basal diameter, leaf area index, maximal PSII efficiency, and Chl a+b, but increased intercellular CO₂ concentration, malondialdehyde (MDA), hydrogen peroxide, superoxide anion radical, peroxidase, ascorbate peroxidase, proline and UV-B absorbing compounds. The effect of enhanced UV-B radiation on net photosynthesis rate (P _n ) increased with mean annual precipitation and experimental duration. The effect of enhanced UV-B radiation on MDA decreased with experimental duration. The effect of enhanced UV-B radiation on superoxide dismutase (SOD) increased with the magnitude of enhanced UV-B radiation. Forests rather than grasslands exhibited a positive response of SOD and a negative response of P _n to enhanced UV-B radiation. Therefore, the effect of enhanced UV-B radiation on alpine plants varied with ecosystem types. Local climate conditions may regulate effects of enhanced UV-B radiation on alpine plants.     

Effects of ultraviolet-B radiation on the growth and yield of crop plants

This paper reviews growth chamber, greenhouse, and field studies on the effects of ultraviolet-B (UV-B. between 280 and 320 nm) radiation on agricultural crop plants. Our understanding of the physiological effects of UV-B radiation comes primarily from growth chamber studies, where UV-B is artificially supplied via filtered lamps. Both photosystems I and II, as well as carboxylating enzymes, are sensitive to UV-B radiation. Ultraviolet-B radiation also affects stomatal resistance, chlorophyll concentration, soluble leaf proteins, lipids, and carbohydrate pools. In general, the effects of UV-B radiation are accentuated by the low levels of visible radiation typically found inside growth chambers. Ultraviolet-B radiation has also been shown to affect anatomical and morphological plant characteristics. Commonly observed UV-B induced changes include plant stunting, reductions in leaf area and total biomass, and alterations in the pattern of biomass partitioning into various plant organs. In sensitive plants, evidence of cell and tissue damage often appears on the upper leaf epidermis as bronzing, glazing, and chlorosis. Epidermal transmission in the UV region decreases in irradiated leaves. This decrease is primarily associated with a stimulation in flavonoid biosynthesis and is thought to be a protective, screening response to the deleterious effects of UV-B. A considerable degree of variability exists in sensitivity to UV-B radiation between different species. Approximately 30% of the species tested were resistant, another 20% were extremely sensitive, and the remainder were of intermediate sensitivity, in terms of reductions in total dry weight. In addition to this sizable interspecific variability, there appears to be a similarly wide intraspecific variability in UV-B response. The effects of UV-B radiation on crop yield have only been examined in a limited number of field studies, with ambient levels of UV-B radiation being supplemented with fluorescent sun lamps. Due to various deficiencies, all these field experiments to date have only limited utility for assessing the potential impact of enhanced levels of UV-B on crop productivity.     

The effects of increased UV-B radiation on growth,pollination success,and lifetime female fitness in two Brassica species

The increasing levels of ultraviolet-B (UV-B) radiation reaching the earth's surface caused by ozone destruction have prompted many studies of UV-B effects on plants. Most of these studies have focused on physiological and growth responses of plants to increased UV-B, but these measures may not be closely related to future survival of plant populations. We examined the effects of two different levels of increased UV-B on total female fitness, including seed number and quality, in rapid-cycling strains of Brassica nigra and B. rapa (Brassicaceae). We also measured the effects of UV-B on fitness components, particularly those related to pollination success. Two separate experiments, examining two different levels of UV-B, were performed. Sixty plants of each species were grown under control and enhanced levels of UV-B for a total of 480 plants (60 plantsx2 speciesx2 UV-B levelsx2 experiments). Increased UV-B was generally detrimental to growth and flowering in both species; however, total seed production was actually greater at higher UV-B doses in three of four dose/plant species combinations examined. UV-B had little effect on pollination success or offspring quality in either species. Therefore, in spite of the detrimental effects of UV-B on growth and flowering that we found, there is little evidence that fitness of these plant species would suffer with increasing UV-B, and we caution against using solely physiological or growth measurements to infer effects of UV-B on plant population fitness.