侧柏不同种源对水分胁迫反应的初步研究：水分状况,电导率和叶萎…

模拟土壤干旱条件，从苗木水分状况，细胞相对透性和叶萎蔫表现等３个方面，研究了侧柏５个种源３年生盆栽苗的抗旱性及其差异。试验结果表明，在干旱胁迫下，北方种源苗木较高方种源的水势下降较慢，叶细胞膨压为零时的土壤含量及土壤水势临界值较低，叶细胞相对透性增大较慢，耐旱性较强；生理指标所反映的种源耐旱笥强弱与对叶萎蔫表现的观察结果基本一致；供试种源抗旱能力可排列为：密云〉志丹〉徐州〉黎平。     

干旱胁迫对不同种源沙柳苗木水势和水分利用效率的影响

通过人工模拟方式对5个种源沙柳苗木进行干旱胁迫处理,研究干旱处理不同阶段苗木小枝水势日变化、叶片相对含水量、水分饱和亏缺、保水力及水分利用效率。结果表明:干旱胁迫下5个种源的沙柳苗木小枝水势和叶片相对含水量均下降,而水分利用效率在轻度干旱时呈上升趋势,随干旱胁迫的加剧而下降。干旱处理15天后,民勤种源的沙柳日平均小枝水势下降幅度最大为0.77 MPa,然后依次为达拉特旗0.57 MPa、盐池0.36 MPa、榆林0.25 MPa和乌审旗0.12 MPa,其中民勤种源的苗木在充分供水和干旱胁迫下小枝水势差异达到显著。干旱处理18天后叶片相对含水量分别下降:民勤1.68%、盐池7.03%、达拉特旗7.25%,榆林9.35%和乌审旗11.07%,水分饱和亏缺民勤<盐池<达拉特旗<榆林<乌审旗。结果表明,民勤种源的沙柳抗旱的能力较强,而盐池和达拉特旗沙柳苗木在受到水分胁迫时水分利用效率下降幅度较小,即水分胁迫对苗木干物质的积累影响较小,因此具有更高的经济价值。     

宁夏盐池沙地水分动态研究初探

采用沙地土壤定位研究方法，系统地研究了毛乌素沙地土壤的水分特性及SPAC(土壤-植物-大气连续体)中水势的变化规律。结果表明：(1)经验方程θ=AS^-B对该地区的土壤水分特征曲线有良好的模拟性，该区土壤的水分特性为：持水量低，供水力小，耐旱性差；(2)水分从树叶扩散到大气中的阻力是土壤-植物-大气连续体中水分传输的主要阻力，土壤水势的变化受降雨、土壤蒸发和林木蒸腾的共同影响，林地的土壤水分表现出明显的季节性变化，树木的叶水势日变化呈明显的单峰曲线，树木受到水分胁迫时水势最低值出现的时间前移，大气水势、土壤水势与叶水势之间均具有一定的相关性。     

不同家系马尾松苗木水分参数的研究

应用P -V技术对不同家系马尾松苗木膨压为 0时的渗透势 (φstlp)、充分膨胀的渗透势 (φssat)、膨压为 0时的相对含水量 (RWCtlp)、膨压为 0时的相对渗透含水量 (ROWCtlp)、细胞最大弹性模量 (εmax)和膨压随叶水势下降而下降的速率 (b)等水分参数进行了研究 ,并用反隶属函数的方法对不同家系苗木保持膨压的能力进行综合评价。结果表明各家系马尾松 ψstlp、φssat、RWCtlp、ROWCtlp、εmax和b值都较低 ,显示了较强的保持膨压的能力。综合评价表明 4 5 6、83、2 0家系和台江种源保持膨压的能力最强 ,75、38和 12 7家系保持膨压的能力较强 ,而 2 3、4 6 4和 186家系保持膨压的能力则相对较弱 ,说明马尾松苗木耐旱性存在较大的种内遗传变异。干旱胁迫下 ,对 83家系与 4 6 4家系的研究表明 ,在一定水势范围 ,b值出现一个低值 ,φstlp也有一定程度的下降 ,εmax值有一定程度的上升 ,但升幅不大。说明在一定的干旱胁迫范围内 ,马尾松苗木随着干旱胁迫的加剧渗透调节能力有所提高。     

香椿幼苗表型对自然干旱胁迫的响应

对广西香椿(Toona sinensis)种源2年生实生幼苗盆栽试验,进行持续自然干旱处理,研究自然干旱过程香椿幼苗表型特征变化和耐旱性分析。结果表明:香椿幼苗表型对自然干旱响应很明显,先是顶部嫩叶及顶芽萎蔫,随后小叶萎蔫、失绿变黄、再由黄变褐,茎干顶端往下干枯,最后植株死亡,可将受害程度分为7个等级。植株保持正常时,土壤相对含水量≥85.54%,顶芽萎蔫、小叶变黄、植株小叶全褐、幼苗干枯死亡受害等级中,第1株出现至最后1株出现的土壤相对含水量依次分别为74.31%~52.14%、65.54%~29.33%、43.72%~25.03%、≤23.95%,表现出较高的耐旱性。各受害等级出现的时间范围、土壤相对含水量变化范围有差异和重叠现象,说明香椿幼苗个体间抗旱性有差异性。     

宁夏盐池沙地水分动态研究初探

采用沙地土壤定位研究方法,系统地研究了毛乌素沙地土壤的水分特性及SPAC(土壤-植物-大气连续体)中水势的变化规律.结果表明(1)经验方程θ=AS-B对该地区的土壤水分特征曲线有良好的模拟性,该区土壤的水分特性为持水量低,供水力小,耐旱性差;(2)水分从树叶扩散到大气中的阻力是土壤-植物-大气连续体中水分传输的主要阻力,土壤水势的变化受降雨、土壤蒸发和林木蒸腾的共同影响,林地的土壤水分表现出明显的季节性变化,树木的叶水势日变化呈明显的单峰曲线,树木受到水分胁迫时水势最低值出现的时间前移,大气水势、土壤水势与叶水势之间均具有一定的相关性.     

水分胁迫对云南松苗生长及生物量的影响

以2年生云南松盆栽苗为试验材料,采用称重控制土壤含水量的方法,设置正常水分(T1)、轻度干旱(T2)、中度干旱(T3)和重度干旱(T4)4个处理,研究水分控制对云南松苗生长、水势、生物量及其相关性的影响。结果表明:1随着干旱程度加剧,云南松幼苗株高、地径生长量逐渐增加,土壤和叶片水势呈现下降趋势,根、叶、茎生物量增量占总生物量增量的百分比逐渐增加,根冠比逐渐增大。2苗高与地径、土壤水势与叶水势都呈现正相关关系,生长指标与水势指标大体呈现负相关关系。在4种水分处理下云南松苗木的生长指标与生物量指标之间呈正相关关系,且相关性均达显著相关水平。研究表明随着干旱的加剧,云南松苗木的生物量增量分配到根系的生物量增加,而分配到茎、叶器官上的生物量减小,以此来提高自身的抗旱能力。     

赤峰36号杨幼苗对水分协迫的生理响应

以赤峰36号杨1 a生幼苗为材料,采用渗透胁迫处理的方法,研究杨树幼苗生理指标对水分不同强度胁迫的响应,结果表明:在3种水分强度胁迫下,杨树幼苗各生理指响应不同,当PEG体积分数为10%时,苗木水势和POD活性较对照变化明显,但MDA含量和质膜相对透性变化不显著,说明该强度的水分协迫未对杨树幼苗造成生理伤害;当PEG质量分数为15%时,虽然MDA含量较对照变化不显著,但苗木水势、POD活性和质膜相对透性却发生了显著变化,尤以质膜相对透性变化明显,说明该强度的水分协迫已对细胞造成了伤害;当PEG质量分数达到20%时,4种生理指标较对照均出现显著变化,说明该强度的水分胁迫对幼苗造成了严重伤害。     

华南地区5种苗木叶水势与土壤含水量的关系

利用盆栽模拟干旱胁迫条件,研究华南地区速生树种尾巨桉、竹柳以及石灰岩地区常见造林树种石斑木、楝叶吴茱萸、任豆苗木土壤含水量与叶水势关系,并从叶水势变化角度对5种苗木的保水能力和抗旱能力进行评价。试验结果表明:1通过拟合土壤含水量与叶水势关系得出:石斑木以乘幂方程拟合最好,R2=0.98(P<0.01);尾巨桉、任豆、竹柳和楝叶吴茱萸以对数方程拟合最好,R2>0.92(P<0.01)。2石斑木和竹柳在整个干旱过程中能保持较高的叶水势,说明其保持水分的能力较强,具有较高的延迟脱水的能力;尾巨桉、楝叶吴茱萸、任豆在受到中度和重度干旱胁迫时叶水势急剧下降,保持水分的能力较弱。3在干旱胁迫条件下,3个石灰岩树种中石斑木叶水势降低较快,且在土壤含水量相同时石斑木叶水势显著高于任豆和楝叶吴茱萸,说明石斑木抗旱性强于楝叶吴茱萸和任豆;而2个速生树种以竹柳的水势降低较快,表现出较强的抗旱性能。     

干旱胁迫对杨树气体交换与荧光参数的影响

以白杨派和黑杨派杨树的盆栽苗为试材,分析了不同干旱胁迫程度对5个杨树的气体交换参数与荧光参数(Fv/Fm、Fmv/Fms)的影响,并对不同树种的耐旱性进行了综合评价。结果表明:①5种杨树净光合速率与蒸腾速率均随苗木叶水势的下降而呈明显下降趋势;在水分胁迫初期,欧洲黑杨和银白杨的净光合速率呈现明显的上升趋势。②在中度干旱胁迫前,5个供试杨树的水分利用效率大部分随叶水势的下降有增大现象。③不同树种的Fv/Fm随叶水势降低总体上呈逐渐下降趋势。④与Fv/Fm相比,Fmv/Fms能更直接地反映光合机构的实际光能捕获能力。⑤当苗木叶水势为-1.5 MPa时,5个树种耐旱性的综合评价结果为:转Bt基因欧洲黑杨>欧洲黑杨>银白杨>银灰杨为欧洲山杨,综合指数评价结果与采用单一指标中的水分利用效率完全一致,与净光合速率相近;水分利用效率证明是一种较为可靠的树种耐旱性评价指标。     

Geographical variation in water relations, hydraulic architecture and terpene composition of Aleppo pine seedlings from Italian provinces

Ecotypic variations in leaf conductance, soil-to-leaf hydraulic conductance, components of tissue water potential, hydraulic architecture parameters and xylem embolism were examined in greenhouse-grown two-year-old Aleppo pine (Pinus halepensis Mill.) seedlings from six origins representing the geographic range of the species in Italy. Cortical resin composition of the seedlings was also determined. Measurements were made on well-watered seedlings and on seedlings subjected to recurring severe drought. Drought-stressed seedlings had lower mean leaf conductances, transpiration rates and soil-to-leaf hydraulic conductances than well-watered seedlings. They also exhibited more negative osmotic potentials, higher relative water deficit at incipient plasmolysis, but a similar maximum modulus of elasticity. Drought-stressed seedlings showed a higher degree of xylem embolism, a lower Huber value, lower leaf specific conductivity and lower specific conductivity than well-watered seedlings. Drought-stressed seedlings of provenances from more xeric habitats (Tremiti, Porto Pino and Mottola) had greater leaf conductances, transpiration rates and soil-to-leaf hydraulic conductances than drought-stressed seedlings of provenances from more mesic habitats (Imperia, Otricoli and Vico del Gargano). They also showed higher osmotic adjustment and a lower degree of xylem embolism. Among provenances, there were no significant differences in hydraulic architecture parameters in response to the drought treatment; however, Tremiti and Porto Pino seedlings displayed smaller drought-induced reductions in specific conductivity and leaf specific conductivity, respectively, than seedlings from other provenances. These differences suggest that seedlings from xeric provenances, especially Tremiti, have greater resistance to desiccation than seedlings from mesic provenances. No clear association was found between terpene variability and the other traits investigated, although terpene composition was related to the geographical distribution of the provenances. We conclude that the drought-tolerance responses of Tremiti make it a more suitable provenance than the others for establishment on sites prone to severe soil water deficits.     

不同种源文冠果叶片气孔分布特征对水分胁迫的响应

[目的]探究不同种源文冠果叶片气孔分布特征对水分胁迫的响应,了解其耐旱性差异,为节水耐旱文冠果种源的选择提供依据。[方法]以集中分布在华北地区的3个不同种源文冠果幼苗为研究对象,通过盆栽控水方法设置充足水分(W1)、正常供水(W2)、轻度干旱(W3)和重度干旱(W4)4个水分梯度,采用指甲油印迹技术,研究不同种源文冠果叶片气孔分布特征对水分胁迫的响应。[结果]表明:不同种源文冠果的气孔均分布在叶片的下表皮,随着干旱胁迫程度的加剧,气孔变得小而多,趋于旱生植物的叶片气孔分布结构特征;气孔分布特征对水分胁迫的响应存在显著的差异性,与河南三门峡、山西晋中两个种源相比,河北承德种源叶片在不同水分胁迫处理下均具有小而多的气孔,以及较强的气孔调节能力。[结论] 3个种源文冠果叶片气孔分布特征均存在着不同程度的趋于旱生结构;河北承德种源文冠果叶片气孔器比其他2个种源均相对小而多,且调节能力强,属华北地区抗旱优良种源。     

Ecophysiology of Acer rubrum seedlings from contrasting hydrologic habitats: growth,gas exchange,tissue water relations,abscisic acid and carbon isotope discrimination

Eight red maple (Acer rubrum L.) provenances, four each from wet and dry sites, were grown under the same conditions and their physiological responses to soil water availability investigated. Under well-watered conditions, seedlings of wet-site provenances grew faster and had consistently higher net photosynthesis, leaf conductance, maximum carboxylation rate, maximum rate of coupled photosynthetic electron transport, apparent quantum use efficiency, light-saturated photosynthesis and dark respiration than seedlings of dry-site provenances. Under conditions of low soil water availability, only dry-site provenances responded with decreased osmotic potential at full hydration and at the turgor loss point; however, provenances from wet sites showed a smaller reduction in absolute growth rate, a greater reduction in gas exchange and a greater increase in abscisic acid concentrations than dry-site provenances.     

Phenologies of sixteen European provenances of sessile oak growing in Scotland

Budburst, budset, leaf yellowing, growth, and frost damage wereassessed on 2- to 4-year-old transplants of 16 provenances ofsessile oak (Quercus petraea) collected in six European countriesand grown in Scotland. There were significant differences indates of budburst between provenances. Provenances from Franceand Austria burst bud earlier than the others (P > 0.05). Budburst date was negatively correlated with altitude of provenanceorigin but positively correlated with latitude, indicating thatsouthern provenances burst bud earlier than northern provenancesand are therefore more prone to spring frost damage. Although there were no significant differences of growth betweenprovenances, French provenances tended to grow later in autumnthan provenances originating in other countries. Consequentlyplants from these French provenances were more badly damagedby autumnal frosts (P > 0.05) than plants from other provenances.Budset and leaf yeljowing in late September were positivelycorrelated.     

Leaf water relations of Eucalyptus cloeziana and Eucalyptus argophloia in response to water deficit

Leaf water relations responses to limited water supply were determined in 7-month-old plants of a dry inland provenance of Eucalyptus argophloia Blakely and in a humid coastal provenance (Gympie) and a dry inland provenance (Hungry Hills) of Eucalyptus cloeziana F. Muell. Each provenance of E. cloeziana exhibited a lower relative water content at the turgor loss point, a lower apoplastic water content, a smaller ratio of dry mass to turgid mass and a lower bulk modulus of elasticity than the single provenance of E. argophloia. Osmotic potential at full turgor and water potential at the turgor loss point were significantly lower in E. argophloia and the inland provenance of E. cloeziana than in the coastal provenance of E. cloeziana. There was limited osmotic adjustment in response to soil drying in E. cloeziana, but not in E. argophloia. Between-species differences in water relations parameters were larger than those between the E. cloeziana provenances. Both E. cloeziana provenances maintained turgor under moderate water stress through a combination of osmotic and elastic adjustments. Eucalyptus argophloia had more rigid cell walls and reached lower water potentials with less reduction in relative water content than either of the E. cloeziana provenances, thereby enabling it to extract water from dryer soils.     

美国皂角不同种源抗旱性评价与筛选

选择引种表现生长好、保存率较高的11个美国皂角种源,调查种源的根系特征,测定各种源叶片解剖结构和水分生理指标,并采用模拟干旱生境的方法,进行干旱胁迫处理,测定不同土壤含水率时各种源叶片游离脯氨酸含量和外渗电导率。结果表明：16、18、22号种源具备较强的适应干旱生境的基础,具有相对较高的抗旱性。     

木荷苗木性状的种源变异和地理模式

利用来自7省区36个木荷种源在浙江淳安和福建建瓯两试验点的苗期测定材料,研究其苗木生长、根系特征和叶片形态等12个性状的种源差异及其地理变异模式。方差分析结果显示,除主根长、侧根长和叶片颜色在种源间无显著差异外,其它性状的种源效应都达到显著或极显著水平。种源苗木性状与产地地理气候因子的相关分析发现,苗高、叶片特征(叶片数、叶片宽、叶片厚)及秋末嫩叶颜色等呈典型的纬向变异模式,产地温度则是造成这种纬向变异模式的主要环境作用因子。与北部种源比较,南部种源生长快,叶片数量多,但叶片较薄较窄,其秋末嫩叶颜色变化对寒冷信号反应敏感。影响木荷种子性状表型差异的主导因素是产地的年降水量。以苗高为标准,分别在两地点初选出优良种源10个,它们多来自25°N左右的木荷自然分布区。     

Water and nutrient supply regimes and the water relations of juvenile leaves of Eucalyptus globulus

Pressure-volume analysis was used to study effects of irrigation and fertilization on the water relations of newly expanded juvenile leaves of Eucalyptus globulus Labill. seedlings growing in Portugal's Atlantic region. In May, at the beginning of the dry season, fertilization and irrigation treatments had no significant effects on the water relations parameters investigated. In September, at the end of the dry season, leaves from non-irrigated plants had a significantly higher apoplasmic water content and a higher dry weight/turgid weight ratio than leaves of similar physiological age from irrigated trees. The osmotic potential at full turgor and the water potential at the wilting point were lower in non-irrigated than in irrigated plants. Changes in osmotic potential at full turgor were negatively correlated with changes in dry weight/turgid weight ratio, suggesting that reductions in osmotic potential at full turgor were largely the result of decreases in cell size. Fertilization had no detectable effect on these variables or on leaf tissue bulk modulus of elasticity. Tissue elasticity was also unaffected by irrigation. Independently of water and nutrient supplies, leaf elasticity was higher and relative water content at the wilting point lower in leaves sampled in May than in leaves sampled in September. In non-irrigated plants, leaves sampled in September had a lower tissue elasticity and a lower osmotic potential at full turgor than leaves sampled in May, indicating that leaves produced at the end of the dry season generate lower water potentials as turgor is lost than leaves expanded early in the season.     

油松、华北落叶松抗旱特性的研究

进行了油松，华北落叶松苗木盆栽试验，在土壤由湿（适宜）到严重干旱的变化过程中，测定了苗木的凋萎系数，叶片水势，根系活力，蒸腾强度，观察了苗木生长的外观反应。对两树种的抗旱性能进行了综合评价，结论是：油松的抗旱性能优于华北落叶松。     

乐东拟单性木兰地理种源变异与选择研究

对乐东拟单性木兰14个种源种子、苗期以及幼林期生长性状进行了调查分析.结果表明:种子千粒质量、苗高、地径、叶长和叶宽等5个性状在种源间差异极显著;造林保存率种源间差异显著,来自北部的种源,如浙江龙泉种源保存率较高,而来自南部的海南尖峰岭种源保存率较低;幼林期4年生树高、5年生树高和胸径、6年生树高和胸径等5个主要生长性状种源间差异均达到极显著水平,其生长性状广义遗传力为0.855～0.930,说明乐东拟单性木兰幼林期主要生长性状的表型差异主要受遗传因素的控制;乐东拟单性木兰苗高和地径与纬度负相关,表明随种源纬度的升高,乐东拟单性木兰种源苗期生长有减小趋势;乐东拟单性木兰幼林期树高和胸径与经度正相关,与纬度极显著正相关.根据乐东拟单性木兰种源幼林期试验结果,选择出浙江龙泉、福建顺昌和湖南新宁3个优良种源.通过聚类分析,把乐东拟单性木兰种源初步划分为3个区:西部种源区、东部种源区和南部种源区.