干旱胁迫对竹柳光合特性的影响

采用盆栽控水的方法,设置5个处理对竹柳幼树进行干旱胁迫实验(分别为浇水到土壤田间持水量的80%后,依次停水16 d、12 d、8 d、4 d和0 d),分析了竹柳在不同干旱胁迫处理下的光合指标,并探讨了胁迫结束后复水对竹柳光合指标的影响。结果表明:(1)随干旱胁迫强度的增大,竹柳的净光合速率(Pn)显著降低(P0.05),气孔导度(Gs)和蒸腾速率(Tr)总体上呈下降趋势,胞间二氧化碳浓度(Ci)先降低后升高;(2)对胁迫后的竹柳恢复浇水,竹柳的净光合速率(Pn)、气孔导度(Gs)、胞间二氧化碳浓度(Ci)和蒸腾速率(Tr)显著增加;(3)竹柳通过叶片变黄,萎蔫卷曲,干枯脱落,顶芽萎蔫下垂的避旱策略来应对干旱胁迫。     

Leaf physiology and sugar concentrations of transplanted Quercus rubra seedlings in relation to nutrient and water availability

Newly planted seedlings incur transplant stress resulting from poor root-soil contact, which limits access to soil moisture and nutrients and reduces growth for one or more growing seasons. Controlled release fertilizer (CRF) applied at planting may reduce transplant stress by augmenting rhizosphere nutrient availability yet with potential risk of root system damage due to elevated fertilizer salt concentrations, which may be further exacerbated by drought. Under controlled conditions, we examined northern red oak (Quercus rubra L.) leaf physiological parameters and soluble sugar concentrations in response to varying nutrient levels (via CRF application) and moisture availability gradients ranging from drought to flooding. Net photosynthetic rates, transpiration rates, and chlorophyll fluorescence parameters responded positively to CRF application, and no interactions were observed between CRF and moisture availability; however, CRF did not increase soluble sugar concentrations. No effects of short-term drought were observed, but flooding exerted a rapid negative influence on net photosynthetic rates, transpiration rates, and chlorophyll fluorescence parameters; flooding also elevated soluble sugar concentrations, indicative of disrupted carbon partitioning and a much greater sensitivity to root-zone hypoxia than to drought in this species. Lack of interactions between CRF application and soil moisture availability indicates relatively similar responses of fertilized seedlings across moisture gradients.     

干旱胁迫对真桦光合特性及渗透调节物质含量的影响

以真桦盆栽幼苗为试材,研究干旱胁迫对真桦叶片光合作用和渗透调节物质含量的影响。结果表明:干旱胁迫使真桦幼苗净光合速率、蒸腾速率和气孔导度显著降低,降低幅度随胁迫程度的加剧而加大。胁迫初期,轻度和中度干旱胁迫组真桦幼苗净光合速率降低的同时气孔导度和胞间CO2浓度同时降低,光合速率降低的主要原因是气孔因素;胁迫中期和后期,各干旱处理组光合速率降低的同时胞间CO2浓度均显著升高,非气孔限制是净光合速率降低的主要原因。真桦在干旱胁迫过程中,可溶性蛋白变化不显著,可溶性糖含量增加,为主要的渗透调节物质。     

Carbon unloading in roots in relation to root senescence in Cercis chinensis seedlings under drought stress

When Cercis chinensis seedlings suffered from drought treatment, net photosynthetic rates had been significantly reduced at the end of the drought treatment. Compared with the control, the activities of acid invertases in roots had increased 5 and 11 days after drought treatment. Seventeen days after drought treatment, the activities of acid invertases in roots were significantly decreased, while activities of alkaline invertases in roots had also been significantly reduced. As the moisture in culture media decreased, so the activities of sucrose synthases in leaves decreased slightly. In roots, their activities had significantly increased 5 and 11 days after drought treatment. The contents of fructose in roots reduced as the moisture in culture media decreased and 11 and 17 days after drought treatment the reduction was significant. The content of glucose in roots clearly did not change as drought stress occurred further, but was still less than that in the control seedlings. Similarly, the content of sucrose reduced as the moisture in culture media decreased. At the beginning of the drought stress, the content of sucrose was significantly higher than that in the control and afterwards there were no differences between drought-treated seedlings and the control. The gradient of the sucrose content between leaves and roots was 0.0982 mg·g–1 FW 17 days after drought treatment, while the gradient of the seedlings under normal condition was 1.3832 mg·g–1 FW. The sucrose concentration gradient reduced by 92.9%. The reduction in the sucrose content gradient under drought stress decreased the sucrose partitioning in roots. Therefore, our results support the hypothesis of ‘shared control’.     

马尾松适应低磷胁迫的生理生化响应

采用单因素砂培方法,在温室内通过人工控制磷元素浓度的方法,研究马尾松在低磷胁迫条件下的生理生化响应.结果表明:根冠比提高是马尾松对低磷胁迫的一种主动适应性反应机制;低磷逆境下,马尾松针叶的可溶性糖和脯氨酸含量增加,而叶绿素和可溶性蛋白含量降低;叶绿素和可溶性蛋白含量的降低导致马尾松针叶净光合速率下降;低磷条件下,马尾松针叶的净光合速率和蒸腾速率降低、暗呼吸速率升高是影响其生物量的主要原因之一;马尾松针叶MDA含量、保护酶活性(POD、SOD)增加,这2方面形成一个动态平衡是马尾松适应低磷胁迫的主要生理响应机制之一.     

Effect of soil water changes on photosynthetic characteristics of Taxodium distichum seedlings in the hydro-fluctuation belt of the Three Gorges Reservoir area

Four different kinds of water treatment were applied to examine the photosynthetic characteristics of baldcypress (Taxodium distichum) seedlings in the hydro-fluctuation belt of the Three Gorges Reservoir area. The aim was to shed light on the physio-ecological adaptation of this species to changing water levels for revegetation purposes. The water treatments were normal growth water condition (CK), light drought water stress (T1), growth under soil water saturation (T2) and growth with soil submersion (T3). T3 had the lowest content of photosynthetic pigment; T1 and T2 did not differ from CK in the content of chlorophyll and carotenoid. The ratio of chlorophyll a to b in the four groups ranged from 2.04 to 2.69 and the ratio of chlorophyll to carotenoid from 3.08 to 4.51. In group T1, the seedling of baldcypres had lower apparent light use efficiency, lower apparent CO₂ use efficiency and a lower net photosynthetic rate, with the net photosynthetic rate 24.9% lower than that of group CK. However, T2 and T3 did not differ from CK in apparent light use efficiency, apparent CO₂ use efficiency and net photosynthetic rate. Water use efficiency of the four treatments consistently increased as treatment was prolonged; the average water use efficiency of T3 was the lowest while that of CK was the highest. Correlation analysis showed that the net photosynthetic rate of baldcypress seedlings was positively related to transpiration rate, stomatal conductance, water use efficiency, apparent light use efficiency and apparent CO₂ use efficiency, but highly negatively related to the ratio of chlorophyll a to b. Net photosynthetic rate was not significantly related to the contents of chlorophyll and carotenoid, the ratio of chlorophyll to carotenoid, relative air humidity and intercellular CO₂ concentration. The transpiration rate was positively correlated with stomatal conductance and negatively related to water use efficiency. The results showed that different water treatments could effectively influence the baldcypress seedlings’ content of photosynthetic pigment, leaf gas exchange and apparent resources use efficiency. The results verified that the species T. distichum takes on the features of a water-tolerant and hydrophilic plant, which can be considered as one of the species for the building of a forest protection system for the hydro-fluctuation belt in the Three Gorges Reservoir area. Baldcypress should not be planted in drought-stricken soils. __________ Translated from Acta Ecologica Sinica, 2005, 25(8) [译自:生态学报, 2005, 25(8)]     

干旱胁迫下刺槐无性系光合生理适应性研究

通过盆栽试验,研究了皖1号(W1)、鲁1号(L1)、鲁59号(L59)和鲁78号(L78)4个刺槐无性系在持续土壤干旱胁迫下的光合生理适应性。结果表明:在土壤持续干旱胁迫下所有无性系的净光合速率都迅速降低。而无性系之间有着不同的适应方式,其中,W1和L1对干旱胁迫反应敏感,在胁迫初期气孔导度、蒸腾速率迅速下降,水分利用效率迅速增加,有着很强的水分控制能力;而L59和L78气孔导度在胁迫后期才明显降低,而且蒸腾速率下降幅度较低,但在整个胁迫过程中保持较高的净光合速率,说明有着高的光合能力。     

水分胁迫对3个枣品种光合特性及水分利用率的影响

对朝阳地区常见的3个品种枣苗(大平顶枣、金铃圆枣、三星大枣)2年生嫁接苗进行4个不同的土壤控水处理,测定出3个品种枣苗在不同水分胁迫条件下的净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、胞间CO2浓度(Ci)等光合特性指标,并计算水分利用效率,以探讨水分胁迫对3个枣品种光合特性及水分利用率的影响,结果表明:土壤水分的变化与净光合速率和气孔导度的变化呈正比关系;在重度胁迫条件下,随着胁迫时间的增加,3个枣品种胞间CO2浓度值接近直线上升状态;随干旱胁迫强度加大,蒸腾速率呈下降趋势。三个枣品种抗旱性大小顺序为三星大枣金铃圆枣大平顶枣。     

花吊丝竹对干旱胁迫的光合和生理响应

通过盆栽实验,研究了花吊丝竹在自然耗水的干旱胁迫处理下土壤含水量、叶片水势、叶片光合作用参数、叶绿素荧光参数以及相关酶类生理指标的变化。结果表明:(1)干旱胁迫下,土壤含水量与叶片水势显著下降,叶片的净光合速率、气孔导度和蒸腾速率均有不同程度下降,胞间CO2浓度呈先降后升的趋势,而气孔限制值则呈先升后降的趋势,说明轻度干旱胁迫下,气孔限制是花吊丝竹净光合速率降低的主要因素,重度干旱胁迫下,非气孔限制是净光合速率降低的主要因素。(2)花吊丝竹叶片光系统Ⅱ的实际光化学效率、表观光合电子传递速率和非光化学猝灭系数在胁迫后段(15~30 d)呈显著下降趋势,而叶片初始荧光在后期呈上升趋势,表明随胁迫程度加重,PSⅡ的结构受到较严重的损伤。(3)随干旱时间的延长,脯氨酸和丙二醛的含量均显著上升,而超氧化物歧化酶和过氧化氢酶的活性则先升后降,这表明随胁迫程度加深花吊丝竹细胞结构被破坏。综上所述,干旱胁迫环境下,花吊丝竹叶片光合作用和保护酶类均发生相应的变化,其自身能够提高叶片对光能的捕获能力、提升光能转化效率、增强叶片中的酶活性以及减少热能的耗散等形式,实现对干旱胁迫较强的忍耐性和较好的适应性。     

盐胁迫对桑树幼苗光合生理生态特性的影响

采用盆栽加盐的方式来人工模拟盐胁迫环境,通过设置0(不加盐),0.1%,0.3%,0.5%和0.7%5个盐分梯度,研究NaCl胁迫对桑树幼苗光合作用及其光响应和CO2响应的影响.结果表明:0.1%NaCl对桑树幼苗的光合生理生态特性没有明显影响;当NaCl浓度≥0.3%时,盐胁迫显著降低桑树幼苗的净光合速率(Pn),气孔导度(GB)、蒸腾速率(TT)、水分利用率(WUE)、光能利用效率(SUE)和羧化效率(CUE),增加胞间CO2浓度(Ci).造成桑树幼苗Pn降低的效应是由非气孔因素和气孔因素2者协同作用的结果;低盐浓度处理时,桑树幼苗Pn降低主要是气孔因素控制的,而高盐浓度处理时,则主要受非气孔因素控制.在光响应和CO2响应过程中,光强和CO2浓度对各种处理的桑树幼苗净光合速率具有显著影响,但其影响的程度和盐浓度密切相关,且盐处理浓度越大,其影响效果越低.此外,盐胁迫能显著降低桑树幼苗的表观量子效率(AQY)、表观羧化效率(ACE)和光饱和点(LSP),增加光补偿点(LCP)、CO2补偿点(CCP).     

水分胁迫下2个牡丹品种生理生化差异比较

牡丹(Paeonia suffruticosa),芍药科,芍药属,是我国的传统名花,有数千年的自然生长和2000多年的人工栽培历史,具有重要的观赏价值、药用价值、食用价值和商品价值(王莲英,1997;李嘉钰,1998)。牡丹生长耐旱怕涝,过多的土壤水分易造     

干旱胁迫对4个油茶品种苗木生理生化指标的影响

为给耐旱性油茶品种的选育提供科学依据,以‘华鑫’‘华硕’‘长林40’和‘长林4号’这4个红壤丘陵区主栽油茶品种2年生嫁接苗为研究材料,采用盆栽控水的方法,分别设置了重度干旱胁迫、中度干旱胁迫和对照3种处理进行试验,对4个油茶品种在不同干旱条件下11个生理生化指标的变化情况进行了观测,并采用隶属函数法对4个油茶品种苗木的抗旱性进行了综合评价。试验结果表明:随着干旱程度的加重和干旱时间的延长,4个油茶品种苗木叶片叶绿素含量都有不同程度的降低,其中‘华硕’的下降幅度最大,为40.96%;其净光合速率、气孔导度、叶片蒸腾速率都呈下降趋势,其平均下降率分别为12.81%、48.03%、42.54%;其超氧化物歧化酶、过氧化物酶、可溶性糖、游离脯氨酸随着干旱条件的变化均呈现出先升后降的变化趋势,而其丙二醛含量则呈持续增长趋势。隶属函数分析结果表明,4个油茶品种抗旱性的强弱顺序为:‘长林40’>‘长林4号’>‘华硕’>‘华鑫’。     

水分胁迫下新西伯利亚银白杨光合能力变化

采用室内盆栽试验,研究不同程度水分胁迫24 d对新西伯利亚银白杨叶片光合生产力和渗透调节物质含量的影响.结果表明：水分胁迫抑制了新西伯利亚银白杨幼苗叶片的光合能力,提高了叶片细胞中可溶性蛋白质含量,并影响了叶片中可溶性糖含量.随着胁迫强度和胁迫时间的增加,叶片净光合速率、蒸腾速率和气孔导度均显著减小.叶片净光合速率与蒸腾速率和气孔导度呈极显著正相关关系,与土壤含水量呈显著正相关关系.气孔导度蒸与腾速率呈极显著正相关关系,与土壤含水量、可溶性糖含量呈显著正相关关系.蒸腾速率与可溶性糖含量呈显著正相关关系.在土壤相对含水量≥25％的条件下,净光合速率下降主要由气孔因素导致.在土壤相对含水量＜25％的条件下,净光合速率下降主要由非气孔限制导致.     

干旱胁迫对麻栎无性系蒸腾作用的影响

以13个3年生麻栎无性系为研究对象,采用盆栽试验方法,研究了在持续干旱胁迫条件下的麻栎无性系土壤水势、叶片水势光合速率和蒸腾速率变化规律及其关系。结果表明,随着干旱胁迫的加剧,13个麻栎无性系土壤水势呈现出不断下降的变化趋势,叶片水势的变化无一致规律,光合速率则先下降而后上升,蒸腾速率的变化规律不尽相同。在13个麻栎无性系中,2、4、5、7、9和16号无性系的蒸腾速率、叶片水势和光合速率具有相同规律,随着干旱胁迫的加剧先下降而后上升,具有较强的适应干旱逆境的能力。对不同干旱条件下无性系的蒸腾速率、土壤水势、叶片水势和光合速率的相关性分析发现,干旱胁迫7天时,蒸腾速率和光合速率达极显著正相关;干旱胁迫12天时,蒸腾速率和土壤水势间呈极显著负相关,光合速率与土壤水势呈显著负相关;干旱胁迫17天时,蒸腾速率与光合速率呈显著正相关。     

Growth and photosynthetic responses of Gallesia integrifolia (Spreng.) Harms and Schinus terebinthifolius Raddi seedlings in dense shade

We analyzed the growth and photosynthetic behavior of Gallesia integrifolia (‘pau-d’alho’) and Schinus terebinthifolius (‘aroeirinha’) under shade, seeking to obtain ecophysiological information for introducing seedlings of those species in previously established cacao agroforestry systems. Considering that light intensity under the shade of cacao trees varied between 5 and 10% daylight, 5 months old seedlings were exposed to four irradiance levels (25, 17, 10 and 5% daylight) for 92 days. With shade increase both species displayed trends of decrease leaf mass per unit leaf area, leaf area per plant (LA), relative growth rate (RGR) and net assimilation rate (NAR), and increase leaf area ratio (LAR). The mean values of light-saturated net photosynthetic rate (P _nmax) in 25 and 5% daylight were 12.8 and 8.0 μmol CO₂ m⁻² s⁻¹ for G. integrifolia and 17.9 and 7.4 μmol CO₂ m⁻² s⁻¹, respectively, for S. terebinthifolius. Based on the measurements of photosynthetic photon flux density and estimated values of photosynthetic saturated irradiance (Is) we concluded that, in all shaded conditions, the leaves of both species were under sub optimal light conditions to reach P _nmax. In spite of the lowest P _nmax values, RGR and NAR were significantly higher for G. integrifolia in all irradiance levels. Differences in growth rates can be explained by the higher values of LA, LAR and leaf mass ratio (LMR), as well as by the lower values of Is, photosynthetic compensation irradiance and dark respiration rates observed for G. integrifolia. Even though seedlings of G. integrifolia presented higher capacity to adapt under conditions of dense shade, we concluded that both species were under stress conditions induced by shade in light environments below 25% daylight. On a practical point of view it is possible to conclude that seedlings of both species should be introduced in light gaps, formed after the fall of big trees, or in places in which cacao trees are cultivated using large plant spacing.     

Photosynthetic physio-response of Taxodium ascendens seedlings to different soil water gradients

Four different kinds of water treatments were applied to study the photosynthetic eco-physiological characteristics of Taxodium ascendens seedlings in the environment of the Three Gorges hydro-fluctuation belt. The four kinds of water treatments were: normal growth water condition (CK), light drought stress (T1), soil water saturation (T2), and soil submersion (T3). The results showed that different water treatments could effectively influence the content of the photosynthetic pigment, leaf gas exchange and apparent resources use efficiency of T. ascendens seedlings. It was also demonstrated that the T. ascendens seedlings could not only tolerate water submersion and wet conditions but also endure a certain degree of drought. To establish a protection forest system in the hydro-fluctuation belt in the Three Gorges Reservoir Area, the species T. ascendens is suitable for planting in conditions of root submersion or water-saturated soil. In case it is planted in drought conditions, this tree species should be watered appropriately in order to keep its normal net photosynthetic rate. Translated from Forest Research, 2006, 19(1): 54–60 [译自: 林业科学研究]     

土壤干旱胁迫对黄栌叶片光合性能的影响

为探索土壤干旱胁迫和光照强度对黄栌光合作用性能的影响规律,应用CIRAS-2型便携式光合作用系统,测定4种土壤水分（对照、轻度、中度和重度胁迫）处理下,3年生黄栌（Cotinuscoggygria var．cinerea）苗木叶片光合作用的光响应过程。结果表明：1）土壤干旱胁迫对黄栌叶片的光合性能参数具有明显影响,随着土壤水分胁迫的加剧,黄栌叶片的光合速率、蒸腾速率、光量子效率明显降低,光补偿点增高,叶片水分利用效率在轻度水分胁迫（土壤相对含水量60-65％）下的水平最高;2）黄栌叶片光合作用对强光胁迫的适应性较强,在较大幅度的强光（有效辐射强度1000-1800μmol·m^-1·s^-1）范围内,均能获得较高的光合速率和水分利用效率;3）黄栌光舍作用对弱光的光能吸收、转换和利用效率（光合量子效率）较低,并随土壤水分胁迫加剧而明显下降。     

不同沙棘品种抗旱性的比较

沙棘抗旱性是多因素作用的结果,如果只利用单因素/单项指标评价其抗逆性,则具有一定的片面性。本研究对干旱胁迫下4个沙棘品种的多项生理生化指标的变化进行比较分析,并通过主成分分析和综合评价发现:乡土中国沙棘(河北丰宁种源)品种的抗旱性最强,引进大果沙棘―乌兰格木品种的抗旱性最差,引进的4个沙棘品种抗旱能力强弱的排序为:丰宁(0.619)> 楚伊(0.445)> 向阳(0.390)> 乌兰格木(0.274)。净光合速率、蒸腾速率、气孔导度、叶水势、谷胱甘肽还原酶和脱落酸的含量可作为沙棘抗旱性的判定指标。随着干旱胁迫的加剧,与对照相比,4个引沙棘品种的净光合速率、蒸腾速率、气孔导度和叶水势均下降,而超氧化物歧化酶活性、细胞膜透性、谷胱甘肽还原酶和四大激素均上升,这说明干旱逆境胁迫影响了沙棘正常的生长发育过程,同时通过内在的生理生化指标的改变来增加其自身对逆境胁迫的抵抗能力。这些将为沙棘抗旱树种的筛选和进一步的杂交育种提供依据。     

干旱胁迫下3个甜角品种幼苗的生理生化响应及抗旱性评价

在大棚模拟持续干旱条件下,测定了3个甜角品种PRAKAYTONG(闪金)、SRITONG(金色)、SRITONGBAO (轻金色)幼苗叶片的细胞质膜透性、丙二醛(MDA)含量、渗透调节物质含量、保护酶活性、叶片含水量和叶绿素含量,研究甜角对干旱胁迫的生理生化响应,并用抗旱系数法和隶属函数法进行抗旱性综合评价.结果表明:随着干旱胁迫时间的延长及胁迫程度的加重,幼苗叶片的细胞质膜透性、MDA含量、脯氨酸含量、可溶性糖和可溶性蛋白含量都呈增加趋势;SOD和POD活性则呈先上升后下降趋势;叶片水分含量和叶绿素呈减少趋势.经抗旱指数法和隶属函数法分析,3个品种的抗旱性从强到弱依次表现为PRAKAYTONG＞ SRITONGBAO＞ SRITONG.     

白梭梭同化枝对干旱胁迫的生理生态响应

对白梭梭同化枝自然水分胁迫下的季节抗旱特征进行研究。结果表明:自然干旱胁迫条件下,不同生长发育时期同化枝的主导抗旱生理因子不同。5月31日至6月29日盛花期间,同化枝内源ABA含量甚微,气孔导度值与光合强度处于生长发育过程的最高水平,可溶性糖含量呈现下降趋势,而脯氨酸含量略有增加,植物通过渗透调节作用适应此阶段轻度干旱胁迫;6月29日至7月26日盛夏期间,ABA迅速积累,气孔导度值降为生长发育过程的最低值,叶绿素分解,可溶性糖与脯氨酸均呈现快速积累趋势,且可溶性糖积累强度大于脯氨酸;8月9日至8月22日同化枝生长发育后期,ABA急剧积累为生长发育过程的最高浓度,气孔导度值有所增大,脯氨酸和可溶性糖保持在高水平平稳变化。此阶段高浓度ABA调节植物生理过程适应干旱的效应受CTK、IAA两种内源激素的抑制,进而抑制脯氨酸和可溶性糖的继续积累。