不同马铃薯品种(系)对增强UV-B辐射的形态响应

UV-B辐射对植物的形态建成有着重要的作用,并且随着地表UV-B辐射的加剧也必将对作物产生影响。本研究通过测定株高、节距、叶面积和根冠比等几个重要的形态指标,分析在增强UV-B辐射条件下马铃薯不同品种的形态响应差异,为综合评价UV-B辐射对马铃薯的影响和耐受性品种选育奠定基础。试验以4个普通和3个彩色马铃薯品种(系)为材料,采用自然光照(CK)和2个增强的UV-B辐射[2.5 k J?m-2?d-1(T1)、5.0 k J?m-2?d-1(T2)]进行处理,分别于处理15 d、30 d和45 d时测定株高、节距、叶面积和比叶重,收获时测定根冠比。最后得出几个形态指标的响应指数(RI),并以累积胁迫响应指数(CSRI)对试验品种的耐受性做出评价。结果显示:在增强UV-B辐射处理后,多数品种呈现株高降低、节距缩短、叶面积减小、比叶重增加的一致性变化趋势,且随着处理强度的增加和时间延长,处理与对照间的差异愈加显著。各品种对UV-B辐射的形态响应存在显著差异,普通品种的株高、节距、叶面积受UV-B辐射抑制较为明显,地上部分的生物量减幅较大,如‘合作88’地上部分(鲜重)RI值在T1、T2处理下分别为-60.28、-70.44,‘丽薯6号’则为-58.61、-66.44;彩色品种受到的影响较小,‘转心乌’地上部分RI值分别为107.75、21.4,‘21-1’为41.49、-45.72。随着地上生物量增长受到显著抑制,地下部分特别是根系也受到明显的影响,普通与彩色品种间根系RI值的变化规律与地上部分一致。由于地上部分生物量的减幅更显著,各品种(系)的根冠比均比对照增大(T2)。T1、T2处理下5个品种的CSRI值显示‘合作88’(-133.35、-240.85)与‘丽薯6号’(-104.09、-160.2)在增强的UV-B辐射处理下形态特征受到了显著的抑制;彩色品种(系)‘转心乌’(275.97、51.26)、‘21-1’(96.8、-142.17)比普通品种‘合作88’、‘丽薯6号’受到的影响相对较小,显示具有一定的UV-B辐射耐受性。     

自然和人为条件下UV-B辐射减弱对烟草抗氧化酶活性的影响

采用盆栽试验,分别在云南玉溪主产烟区海拔高度存在一定差异的通海县(海拔1806.0m)和红塔区大营街(海拔1591.0m)两地,研究了自然条件下和通海县减弱25%、50%和65%UV-B辐射条件下,烟草K326大田生育进程中叶片SOD、POD和CAT等3种抗氧化酶活性与UV-B辐射变化的关系。结果表明:由于在局地范围内两地天气气候特征存在一定差异,致使UV-B辐射随海拔高度的变化与地处低纬高原的云南地区大尺度范围的普遍规律相反,烟草大田主要生长期的太阳UV-B辐射强度为大营街通海。大营街烟叶SOD和POD活性高于通海,减弱UV-B辐射后SOD活性发生不同变化,而POD活性随UV-B辐射减弱而下降,但各处理CAT活性变化几乎一致。从时间动态变化看,3种酶都与UV-B辐射变化呈负相关,SOD和POD活性与UV-B辐射变化相关性较高,表现出较强的累积效应,CAT活性变化几乎不受UV-B辐射变化的影响,7月下旬-8月上旬是各处理烟叶3种抗氧化酶活性差异的主要时期。结果说明,烟叶SOD、POD和CAT活性对UV-B辐射变化响应的敏感性存在较大差异,SOD和POD对UV-B辐射变化较敏感,成熟期是K326叶片SOD和POD活性对UV-B辐射变化响应的敏感时期。     

UV-B辐射强度变化对烤烟光合生理和化学品质的影响

地处低纬高原的云南烟区UV-B辐射强度变化对烟草的质量形成有重要影响。试验设0.252(T0)、0.526(T1)、0.571(T2)和0.616(T3)mW·cm-2共4个UV-B辐射强度处理模拟云南不同海拔高度上UV-B辐射强度的差异,以自然环境为对照(CK),研究其对大田烤烟(品种为K326)叶片光合水平、生理特征和化学品质的影响。结果表明:4个UV-B辐射强度处理中,强度越大对K326叶片Pn、Tr及Gs值产生的影响越大;适当增强的UV-B辐射有利于提升叶片的光合作用能力,可提高和维持叶绿素和类胡萝卜素含量及WUE水平;适量的UVB辐射还可促进烟叶化学成分的协调性,最终提高烟叶化学品质。研究结果可为正确评估UV-B辐射对烟草种植的潜在影响提供一定理论依据。     

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%。     

不同时期减弱UV-B辐射对烤烟部分生理生化特征的影响

采用大棚加盖Mylar膜的方法,在大田条件下研究了烤烟不同生育期（旺长期、生理成熟期和工艺成熟期）减弱UV-B辐射（相当于自然环境下强度的39.59%）对不同叶位叶片含水量（LWC）、比叶重（SLW）、光合色素、类黄酮（FV）和丙二醛（MDA）等的影响。结果表明,旺长期减弱UV-B辐射对烟叶LWC影响较小,但可降低中、下部烟叶的SLW,生理成熟期和工艺成熟期减弱UV-B辐射可降低中、上部叶的LWC,但可提高其SLW值。旺长期和生理成熟期减弱UV-B辐射可降低中部叶的叶绿素a（chl a）、b（chl b）含量,工艺成熟期减弱UV-B辐射后中、上部叶的chla、b含量上升。旺长期和生理成熟期减弱UV-B辐射降低MDA含量,FV和类胡萝卜素（car）变化与MDA基本相反。结果说明,旺长期较强的UV-B辐射有利于提高烟叶的SLW,旺长期和生理成熟期较强的UV-B辐射还可促进chl和car的合成,MDA的变化与FV和car有一定的关系。     

滤减UV-B辐射强度对植烟环境小气候要素的影响

以烤烟（Nicotiana tabacum L.）品种‘K326’为试验材料,采用盆栽方法,以覆盖3种不同厚度透明薄膜滤减UV-B辐射的处理方式进行试验。在成熟初期,于试验设定时间点分别测定50cm和150cm高度处烤烟环境小气候要素,应用多元统计岭回归分析方法分析了滤减自然条件下25%（T1）、50%（T2）和65%（T3）的UV-B辐射强度对各要素的影响。结果表明：叶片周围空气温度（Ta）、光合有效辐射（PAR）和饱和水汽压亏缺（VPD）的日变化曲线总体呈上升趋势,而二氧化碳浓度（Ca）、相对湿度（RH）则呈下降趋势。岭回归分析表明,滤减UV-B辐射对植烟环境小气候要素作用显著,具体表现在T1、T2、T3处理对Ca和RH总体上均具有抑制作用,滤减50%的UV-B辐射对叶片周围Ca的抑制作用最大;滤减UV-B辐射对Ta有明显的促进作用,滤减50%的UV-B辐射对Ta促进作用最强;相对于自然条件而言,滤减65%的UV-B辐射更有利于烟叶对辐射能的吸收和利用;T1处理对VPD具有明显的促进作用,T2处理在不同高度上对VPD作用方向不一致,T3处理的抑制效应则表现不明显,即在不同处理的UV-B辐射强度水平下,植烟环境小气候要素对UV-B辐射的响应存在一定的差异。     

合理密植对不同株型烤烟冠层结构及光合生产特性的影响

【目的】研究不同耐密性烤烟对密植的综合响应,为鉴选耐密品种及烤烟合理密植提供理论参考。【方法】采用两因素裂区试验设计,以云烟97 (塔形,低耐密)、NC71 (腰鼓形,中等耐密)、K326 (筒形,高耐密) 3类株型烤烟为主区,4个种植密度(13890、15150、16660、18510株/hm^2)为裂区,阐明不同株型烤烟农艺性状、冠层结构、物质积累、产量及构成对密植的响应规律。【结果】密植条件下(15150、16660、18510株/hm^2),烤烟株高显著增加,最大叶叶位明显下降,并逐渐表现为"高瘦"形态。品种因素对株高和最大叶叶位影响显著,不同品种间茎围无显著差异。随种植密度的增加,烤烟群体叶面积系数(LAI)呈增加趋势,尤其是耐密品种NC71和K326的LAI显著增加,不同密度间K326品种LAI空间分布变异最低。密植主要通过提高群体干物质生产力(单位面积有效叶片数)弥补单株生产力(上中等烟率、单叶重)的不足,从而获得结构性增产。云烟97品种群体产量以16660株/hm^2时最高,平均较对照(13890株/hm^2)显著增加15.51%;NC71品种群体产量以16660株/hm^2和18510株/hm^2间无明显差异,较对照分别显著增加17.61%和19.37%;K326密植效应最大,以18510株/hm^2群体产量最高,比对照提高24.51%。成熟期云烟97单株干物质在15150株/hm^2后持续下降,降幅范围为8.41%～21.08%,NC71和K326品种则在密度为16660株/hm^2时有显著降低。合理密植可发挥烤烟群体结构性增产潜力,紧凑品种(NC71、K326)的高耐密性表现为个体生理对密植响应迟钝,从而获得功能性增产。【结论】合理密植可充分发挥烤烟群体结构性增产潜力,不同品种耐密性差异主要表现为个体功能对密植响应的迟钝性强弱,本试验条件下,K326、NC71、云烟97品种密植分别为18510株/hm^2、16660株/hm^2、15150～16660株/hm^2时,可实现烤烟群体结构和个体功能平衡。     

铬胁迫对烤烟生长和生理生化指标的影响

本文采用盆栽试验,研究了不同的重金属铬浓度(0、2、40、60、80mg·kg-1)对烤烟K326生长发育和某些生理生化指标的影响,分别测定移栽后25、50、75d烟株主要农艺性状(包括株高、叶片数、节距、茎围、最大叶长叶宽)、生物量、烟叶叶绿素含量、过氧化物酶(POD)活性和超氧化物歧化酶(SOD)活性。结果表明:随着铬浓度增加,烟株主要农艺性状和生物量呈明显下降的趋势,叶绿素a和叶绿素b含量也呈下降的趋势,POD和SOD活性显著下降,随着生育期延长,烟株主要农艺性状逐渐增大,烟叶叶绿素含量呈下降的趋势,SOD活性呈明显上升的趋势,POD活性在移栽50d时最高。     

UV-B增强下施硅对水稻冠层反射光谱特征的影响

通过田间试验,在UV-B增强和施硅条件下,利用ASD便携式手持光谱仪在水稻分蘖期、拔节期、抽穗期和灌浆期选择典型晴天观测冠层光谱曲线,通过计算一阶导数曲线分析光谱的红边参数特征。UV-B辐射设2个水平,即对照(自然光,ambient UV-B,A)和UV-B增强(比自然光增强20%,elevated UV-B,E);施硅设2个水平,即不施硅和施硅(硅酸钠,200kg SiO_2·hm~(-2))。结果表明:UV-B增强下水稻叶面积指数(LAI)和叶绿素含量(SPAD值)降低,而施硅可提高叶面积指数(LAI)和SPAD值,缓解UV-B增强对水稻生长的抑制作用。各处理间水稻冠层光谱的差异主要体现在近红外波段,UV-B增强使水稻近红外波段反射率降低,施硅使近红外波段反射率上升。UV-B增强使水稻光谱红边位置蓝移,施硅使红边位置红移。随着生育期推移,水稻光谱红边位置、红边幅值和红边面积均呈现先增后减的趋势,且在拔节期达最大。     

地表臭氧含量增加和UV-B辐射增强对大豆生物量和产量的影响

利用开顶式气室(OTC)设置4个处理对大豆进行O3与UV-B增强的大田试验,通过观测生物量和产量研究两者对大豆生长的影响。T1为O3含量100nmol/mol的处理,T2为UV-B辐射强度比CK增加10%的处理,T3为T1和T2的复合处理,CK为自然空气。结果表明,O3含量与UV-B辐射增强的单因素对大豆株高、叶面积、茎干重等生物量都有不同程度的负影响,而两者复合后对各生物量的影响效果不一致,在分枝期至结荚期拮抗作用居多,而协同作用则多出现在生育期末期。在整个生育期,各处理均表现为茎分配指数变化幅度较小,CK、T1、T2、T3的根和叶分配指数逐渐降低,且荚分配指数呈快速上升的趋势。由此可见,O3和UV-B辐射单因子胁迫对大豆生物量和产量均产生不同程度的负效应,而两者的复合作用并不是两个单独作用的简单累加。     

增强UV-B辐射对两个烤烟品种主要化学成分的影响

以云南两个烤烟主栽品种“云烟87”和“红花大金元”为试验材料,模拟昆明地区24.65％和39.53％的臭氧衰减时增强的UV-B辐射(分别为T1 5.30 kJ·m-2·d-1和T2 8.50 kJ·m-2·d-1),研究了大田条件下增强UV-B辐射对两个烤烟品种烟叶常规化学成分、质体色素和酚类含量的影响,为揭示UV-B辐射对烤烟化学质量特征的影响机理提供理论依据.结果表明:两种UV-B辐射明显降低了两个烤烟品种的水溶性糖和邻苯二酚含量,同时造成两个烤烟品种全氮、全钾、游离氨基酸、质体色素和类黄酮明显增加.增强UV-B辐射对两个烤烟品种烟碱含量的影响不同,增强UV-B辐射使“云烟87”的烟碱含量增加,使“红花大金元”烟碱含量降低.水溶性糖和总氮含量变化对UV-B辐射的响应说明“云烟87”品种对UV-B辐射更敏感.     

Elevated UV-B radiation modifies the extractability of carbohydrates from leaf litter of Quercus robur

We examined the influence of elevated UV-B radiation on the extractability of carbohydrates from leaf litter of Quercus robur. Saplings were exposed to a 30% elevation above the ambient level of erythemally weighted UV-B (280-315 nm) radiation for eight months at an outdoor facility. UV-B radiation was applied under arrays of fluorescent lamps filtered with cellulose diacetate, which transmitted both UV-B and UV-A (315-400 nm) radiation. Saplings were also exposed to elevated UV-A radiation under arrays of polyester-filtered lamps and to ambient radiation under arrays of non-energised lamps. Abscised leaves were collected, ground and sequentially treated with seven solvents in order to fractionate extractable carbohydrates based on the way in which they are held in the cell wall. Elevated UV-B radiation reduced the extractability of carbohydrates from cell walls of Q. robur. Sodium phosphate buffer at pH 7 extracted 10% less total carbohydrate from leaf material exposed during growth to elevated UV-B radiation under cellulose diacetate-filtered lamps than from leaf material grown under polyester-filtered and non-energised lamps. The cumulative amount of carbohydrate released by sequential extraction with phosphate buffer, CDTA, urea and sodium carbonate was between 5.1% and 7.8% lower from leaf material grown under cellulose diacetate-filtered lamps relative to that from leaves grown under non-energised lamps. Abscised leaves were also digested with Driselase, an enzyme mixture extracted from a basidiomycete fungus. No effects of elevated UV radiation were recorded on the amount of carbohydrate released by Driselase digestion. Regression analyses, using data from a previous field decomposition study, suggested that reduced availability of carbohydrates enhanced the colonisation of Q. robur litter by basidiomycete fungi, which then accelerated the decomposition rate of the litter in soil. We recommend that future studies into the effects of UV-B radiation on plant litter decomposition measure not only the concentrations of chemical constituents of litter, but also determine the availability of litter carbon sources to soil microbes, using methods similar to those used here.     

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.     

Crop phenology modifies wheat responses to increased UV-B radiation

Ozone layer depletion increases the level of ultraviolet radiation reaching the earth's surface affecting both natural and agricultural ecosystems, especially in the Southern Hemisphere. Considering the harmful effects UV-B radiation has on plant growth the future productivity of wheat crops in Southern Chile could be challenged by both (i) the forthcoming level of UV-B increase and (ii) the sensitivity of this crop to higher UV-B radiation. In this study the effect of increased UV-B radiation at different phenophases on a spring wheat cultivar (Pandora) was investigated in two experiments at plant and crop levels under out-door conditions. The experiments consisted of controls, increased UV-B radiation at specific phenophases (from 3 leaf stage to booting 3L-Bo, and from booting to maturity Bo-PM), and increased UV-B radiation for the majority of the crop cycle (from 3 leaf stage to maturity). UV-B radiation was increased by Q panel UV-313 lamps set in plastic framed structures. Control plants were grown either without frames or below the same framed structures as those which received increased UV-B treatments. Phenology, above-ground biomass, grain yield, components, grain protein concentration, leaf area index (LAI), Fv/Fm and pigments were measured at booting and/or at harvest. Above-ground biomass and yield decreased by 11–19 and 12–20%, respectively, when UV-B radiation was increased at the 3L-Bo phase, while no effect was observed when irradiation was applied later in the crop cycle (Bo-PM). No additional UV-B effects to those observed at booting were detected in plants irradiated during the majority of the entire crop cycle (3L-PM). Biomass variation was strongly associated (r = 0.99; P < 0.01) with UV-B/PAR ratio in the sensitive treatments to UV-B increases (3 L-Bo) of both experiments. Flour protein was not affected by UV-B increases at any phenophase evaluated in this study. In both experiments, leaf green area and weight were negatively affected by increased UV-B radiation and no effect on specific leaf area (SLA) was found. Lower Fv/Fm, chlorophyll, carotenoid concentration and carotenoid:chlorophyll ratio were found at crop level (experiment 2) under higher UV-B in the 3L-Bo and 3L-PM treatments. The flavonoid concentration responded differently in the two experiments, probably due to the optimum responses these pigments had to expose UV-B doses.     

UV-B增加对玉米生长发育和产量的影响

在大田栽培和自然光条件下，模拟紫外辐射增加对玉米生长发育、产量和品质的影响。分析结果表明，UV-B增加，导致株高变矮，叶面积降低，绿叶数、叶龄下降，干物重减少，发育期延迟，产量降低，玉米叶片类黄酮含量增加，叶绿素含量降低。这些变化具有随生育期不同而不同的特点。     

Negligible influence of elevated UV-B radiation on leaf litter quality of Quercus robur

We tested whether elevated UV-B radiation applied to Quercus robur, a principal climax species of northern Europe, would influence concentrations of polyphenolics (Folin–Denis tannins and lignin), phenylpropanoid moieties of lignin, carbohydrates (monosaccharides and holocellulose), or nutrient elements (K, Ca, Mg, P and N) in recently-abscised leaf litter. Saplings of Q. robur were exposed for 2 years at an outdoor facility in the UK to a 30% elevation above the ambient amount of erythemally-weighted UV-B (280–315 nm) radiation under arrays of fluorescent lamps with cellulose diacetate filters, which transmitted both UV-B and UV-A (315–400 nm) radiation. Saplings were also exposed to elevated UV-A alone under arrays of lamps with polyester filters and to ambient radiation under non-energised arrays of lamps. We found little evidence that elevated UV-B radiation influenced leaf litter quality. Data pooled for both years indicated an 8% increase in vanillic acid concentration in litter from polyester-filtered lamp arrays, relative to non-energised arrays, and 8% and 6% increases, respectively, in concentrations of acetovanillone in litter from polyester- and cellulose diacetate-filtered lamp arrays, relative to non-energised lamp arrays. Arabinose concentration in litter from cellulose diacetate-filtered lamp arrays was 3% higher than in litter from polyester-filtered arrays, and glucose concentration in litter from cellulose-diacetate filtered lamp arrays was increased by 6%, relative to non-energised arrays. There were no main effects of elevated UV on the concentrations of holocellulose, polyphenolics or nutrient elements. We conclude that exposure to elevated UV-B does not substantially influence the initial chemical composition of Q. robur leaf litter and that any increases in UV-B radiation arising from ozone depletion over northern mid-latitudes will be unlikely to affect nutrient cycling and decomposition in Quercus woodlands through effects on litter quality alone.     

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。