水分条件对红松和西伯利亚红松针叶脯氨酸与叶绿素含量的影响

以盆栽3年生红松和西伯利亚红松为材料,设置4种水分条件,土壤含水量分别为：29％～31％（C）, 22%～24%（L）, 15%～17%（M）和渍水组（W）,研究不同水分条件下红松和西伯利亚红松当年生针叶和往年生针叶的脯氨酸含量和叶绿素含量变化。结果表明：1）脯氨酸含量在不同叶龄和不同树种之间存在差异。红松当年生针叶叶绿素含量高于往年生针叶,而西伯利亚红松则相反。总体上西伯利亚红松的脯氨酸含量高于红松;2）2树种在渍水条件下脯氨酸含量大量积累,红松在处理后一个月即出现胁迫反应,早于西伯利亚红松。土壤含水量在 15%～17%时已对2种红松的往年生针叶产生胁迫,但对红松的胁迫程度大于西伯利亚红松;3）叶绿素积累与2种红松的耐水分胁迫能力相关性不大;4）西伯利亚红松的水分适应范围大于红松;2种红松的当年生针叶的耐水分胁迫能力均大于往年生针叶。     

珍贵树种西伯利亚红松引进的可行性

西伯利亚红松 (Pinussibirica)主产于俄罗斯的西伯利亚地区 ,广泛分布于欧亚泰加林带 ,种内变异非常丰富 ,存在大量优良种质 .该树种具有极强的耐寒性 ,其水平分布可进入北极圈内 (6 8.5°N) ,垂直分布可达树木上限 ,分布区内绝对低温有 - 6 7℃的记录 (红松约 - 5 0℃ ) ,是寒温带针叶林的著名建群种 .而我国的寒温性森林面积很大 ,自然环境条件与西伯利亚红松分布区基本相似或略好 ,但树种较单一 ,西伯利亚红松仅在我国的北疆高山及生态环境最严酷的大兴安岭满归林业局有极少量分布 ,因此在环境条件更好的其他地区引进是完全可能的 .西伯利亚红松的引进不仅可能在短期内解决我们对良种的需求 ,而且可以开展食用松籽的生产试验 ,使我国一向几乎无农业可言的广大高寒林区 ,逐渐成为新兴的坚果林生产基地 .     

西伯利亚红松(Pinus sibirica Du Tour)在大兴安岭的存在

1981年以来赵光仪等以营养器官形态解剖特征,结合生态地理分析,连续报道了西伯利亚红松 Pinus sibirica在大兴安岭的存在,引起争议。1989年秋,我们于大兴安岭满归林业局采到了争议松树的球果,经同主产区的西伯利亚红松及红松P．koraiensis标本对照研究,再次认定大兴安岭争议松树确属西伯利亚红松。从而最终证实了吴中伦先生25年前关于西伯利亚红松存在于大兴安岭的预见,纠正了所谓“漠河红松”30余年的误称。根据10年来调查研究结果绘出了大兴安岭及其毗邻地区红松、西伯利亚红松分布略图,显示了两种松树生态地理学特征的深刻差异。     

低温胁迫对不结球白菜光合及叶绿素荧光特性的影响

以盆栽的耐寒性不同的不结球白菜品系001、007和010为材料,在玻璃温室中对各品系进行常温(CK,昼/夜温度为20℃/15℃)和低温(昼/夜温度为7℃/2℃)处理,研究低温对不结球白菜的冷害指数、光合指标和叶绿素荧光参数的影响.结果表明:低温胁迫条件下,3个品系不结球白菜的净光合速率(Pn)均较CK显著下降,PSⅡ最大光化学效率(Fv/Fm)、电子传递速率(ETR)和光化学猝灭系数(qP)显著降低,而品系001各项指标显著高于其他品系;不同品系非光化学猝灭(NPQ)均呈增加趋势,品系间增加幅度差异不显著.低温胁迫下,品系001叶片吸收的光能中用于有效电子传递的比例较高,光合受抑程度较轻;007和010的电子传递速率显著下降,过剩激发能显著高于001,光合活性受损较严重.研究发现,低温胁迫下各不结球白菜品系非光化学耗散差异不显著,电子传递的有效性和光化学效率的差异是导致各品系耐冷性差异的主要原因.     

新疆阿勒泰地区西伯利亚红松径向生长对气候水文的响应

利用采自新疆阿勒泰地区西伯利亚红松树轮样本,建立树轮标准化年表,对气候水文因子对西伯利亚红松径向生长的影响进行了研究。结果表明: 西伯利亚红松年表包含较高的气候信息,与当年5—6月平均温度、平均最高温度表现出显著的负相关,与当年5—6月帕默尔干旱指数(PDSI)表现出显著的正相关,与当年1—6月降水表现出显著的正相关,与上一年11月额尔齐斯河径流表现出明显的正相关。温度和降水共同影响该地区西伯利亚红松的径向生长,其中生长期前期降水与夏季温度是影响径向生长的关键气候要素。对年表极值年的研究发现,厄尔尼诺-南方振动(ENSO)及全球大尺度环流与西伯利亚红松径向生长存在联系,ENSO通过对中亚上空气旋位置的影响使输送到阿勒泰地区的水汽产生变化,从而影响到西伯利亚红松的径向生长。     

大兴安岭林区引种西伯利亚红松研究进展

西伯利亚红松(Pinus sibirica)是寒温带森林主要成林树种, 具有较强的区域适应性和应用价值, 已成为大兴安岭林区的重要引种树种。文章基于植物引种程序, 从西伯利亚红松引种准备、引种造林试验、引种应用等方面综述了国内外最新研究动态, 并分析当前该树种引种研究存在的不足, 从不同尺度对西伯利亚红松未来可能研究方向进行展望, 以期为西伯利亚红松在大兴安岭林区的推广种植和森林生态系统可持续发展提供科学参考。     

松突圆蚧种群耐寒性的季节变化

采用过冷却点、低温暴露死亡率、冷识别温度和致死中低温累积等指标评价不同季节松突圆蚧的耐寒性.结果表明:各季节松突圆蚧的过冷却点波动在-22.4～-3.1 ℃之间,以冬季雌成虫的平均过冷却点最低(-14.83 ℃),显著低于夏季雌成虫、冬季1龄若虫和初孵若虫(P＜0.01),但其它发育阶段在冬、夏季之间均无显著差异;冬季1龄若虫、2龄性分化前若虫、2龄性分化后雄若虫、雌成虫和种群总体在-20～0 ℃下的死亡率、冷识别温度和致死中低温累积均明显低于夏季;1龄若虫、2龄性分化后雄若虫和种群总体的致死中低温累积与季节性平均气温均呈显著正相关(R＞R0.05=0.950,n-2=2),但各发育阶段的过冷却点与其致死中低温累积的相关性均未达显著水平.松突圆蚧冬季种群耐寒性最强,夏季种群最弱;该虫耐寒性的这一季节适应性并不依赖于过冷却点,而与气温的季节变化密切相关.     

边缘效应带促进红松生长的光合生理生态学研究

以一个经过12a边缘效应带处理的14年生红松幼林生态系统为研究对象,通过对3种宽度(4m,6m,8m)边缘效应带及保留带内红松幼树的光合日进程、碳素日积累量及相关生理生态学因子(光照、气孔导度、小枝木质部水势、叶片温度、叶面饱和蒸气压亏缺)的研究,探讨了造成不同效应带和保留带内红松生长差异的光合生理生态学原因。结果：4m效应带光照不足引起的碳素日积累量过低导致红松生长较差,8m效应带气孔导度过低引起的光合午休现象导致了碳素日积累量低、红松生长较差。8m效应带引起气孔导度下降的因素主要是过强光照引起叶片温度较高、叶面饱和蒸气压亏缺较大以及小枝木质部水势过低。研究认为,太宽的8m带和太窄的4m带都在一定程度上引起了光合生理生态学的不适应,导致生长水平下降,6m宽度的边缘效应带是人工促进红松生长的最佳边缘效应带。     

长白山过渡带红松和鱼鳞云杉径向生长对气候因子的响应

利用树轮生态学方法, 研究了长白山阔叶红松林和暗针叶林过渡带优势树种红松(Pinus koraiensis)和鱼鳞云杉(Picea jezoensis var. komarovii)的生长特征及其与气候因子的关系, 以期揭示气候响应关系的种间差异性。结果表明, 红松和鱼鳞云杉年平均径向生长量与生理年龄显著相关, 红松先于鱼鳞云杉达到最大年生长量, 且红松年平均生长速率显著高于鱼鳞云杉(p < 0.001); 红松和鱼鳞云杉对气候的响应存在差异, 红松与7月份的月平均温度和降水显著正相关, 而鱼鳞云杉与5月平均温度显著正相关, 与5月降水显著负相关。响应面分析进一步证实, 红松生长主要与生长季温度和降水相关, 而生长季初期的降水是限制鱼鳞云杉生长的主要原因。全球变暖有利于红松径向生长, 红松种群有向高海拔上升的可能。     

不同径级的西伯利亚红松树干液流及蒸腾耗水特征的差异

基于热扩散技术,采用TDP法连续监测了新疆喀纳斯国家自然保护区内不同径级西伯利亚红松的树干液流,分析其在生长季内(6~9月)的液流变化及蒸腾耗水特性,为阐明喀纳斯保护区优势树种水分循环机理,以及理解区域尺度上森林生态系统水分循环及其过程应对未来气候变化的响应机制提供依据。结果显示:(1)不同径级西伯利亚红松在晴、阴、雨3种天气条件下的树干液流日动态变化均呈昼高夜低的多峰型曲线,但变化频率和变化幅度差异明显,日最大液流值的排序为晴天阴天雨天。(2)树干液流的发生较光合有效辐射的变化存在明显的滞后效应,不同径级西伯利亚红松的最大液流峰值滞后时间在30~207min。(3)西伯利亚红松的月平均树干液流的大小顺序为7月8月9月6月,且相同径级树干阳生面的液流速率均大于阴生面。(4)西伯利亚红松全株的蒸腾耗水量为7月份的最大,其值占整个生长季的61.8%;且大径级阳生面的蒸腾耗水总量(6 716.79g)和阴生面蒸腾耗水总量(4 649.08g)分别是相应小径级阳生面和阴生面的2.00和2.45倍。(5)气温、空气相对湿度和光合有效辐射是影响西伯利亚树干液流的主要因素,同时0~5cm和20~30cm土壤温度对其影响也较大。研究表明,西伯利亚红松在生长过程中,大径级树干的液流和蒸腾耗水量大于小径级,主要发生部位为树干的阳生面,且在7月份的变化最明显。     

水分胁迫下天然次生灌木山桃和山杏光合气体交换特征

以半干旱黄土丘陵区3年生天然次生灌木山桃(Prunus davidiana)和山杏(Prunus sibirica)为试验材料,采用充分供水、正常供水、轻度胁迫、中度胁迫和重度胁迫5种水分处理,比较了水分胁迫对山桃和山杏光合气体交换参数的影响.结果表明:山桃和山杏的净光合速率(Pn)、胞间CO2浓度(Ci)、蒸腾速率(Tr)、气孔导度(Gs)和水分利用效率(WUE)在不同水分处理之间差异显著.随着水分胁迫的缓解,山桃和山杏的Pn日变化曲线逐渐从单峰型转变成不明显的双峰型;重度水分胁迫下,Pn受到明显抑制,一直维持在较低水平;Pn在轻度或中度水分胁迫下出现最大值,且山桃的日均Pn要高于山杏;Pn降低的原因上午表现为气孔限制因素,而下午则以非气孔限制因素为主.山桃和山杏的Ci日变化规律与Pn基本相反,它们的Tr日变化在轻度和中度水分胁迫下为双峰曲线,并以正常供水条件下日均Tr最大;不同程度水分胁迫下,山桃、山杏的Gs日变化表现出相似的变化规律,且气孔都出现了过早关闭的现象.适度的水分胁迫能够提高山桃、山杏的水分利用效率,同时也降低了Pn和Tr.研究发现,山桃和山杏在水分胁迫下能通过较大幅度降低蒸腾速率来提高其水分利用效率,从而增强其适应干旱环境的能力,它们在黄土丘陵区具有较广阔的发展潜力.     

低温锻炼后桑树幼苗光合作用和抗氧化酶对冷胁迫的响应

以桑树品种“秋雨”为试验材料,研究了桑树幼苗在低温锻炼、冷胁迫和常温恢复期间的光合作用和抗氧化酶活性的变化.结果表明: 12 ℃3 d低温锻炼明显提高了桑树幼苗的抗冷性.3 ℃3 d冷胁迫下,12 ℃3 d低温锻炼后的桑树幼苗叶片净光合速率(P_n)、气孔导度(G_s)和PSⅡ 最大光化学效率(F_v/F_m)明显高于对照(未经低温锻炼)处理的桑树幼苗,而且其在常温下的恢复也较对照桑树幼苗迅速.在12 ℃ 3 d低温锻炼和3 ℃ 3 d冷胁迫期间,桑树幼苗叶片脯氨酸和可溶性糖含量明显增加,而经低温锻炼的桑树幼苗叶片丙二醛(MDA)含量明显低于未经低温锻炼的桑树幼苗,经低温锻炼的桑树幼苗叶片抗坏血酸过氧化物酶(APX)活性则明显高于未经低温锻炼的桑树幼苗.说明渗透调节物质含量增加和APX活性提高在低温锻炼诱导桑树幼苗的抗冷性上发挥着重要的作用.     

The alpine homoploid hybrid Pinus densata has greater cold photosynthesis tolerance than its progenitors

The diploid hybrid tree species Pinus densata inhabits high-altitude regions, usually at higher altitudes than its parental species, P. tabulaeformis and P. yunnanensis. Its success in alpine habitat has been hypothetically attributed to enhanced cold tolerance. We tested this hypothesis by subjecting all three species to cold stress for 33 days (12/5 °C, day/night) and measuring changes in their photosynthetic function. Significant decreases in net photosynthetic rate (P_n), stomatal conductance (g_s) and transpiration rate (E) were observed in all three species in response to cold stress. The depression of P_n was primarily attributable to stomatal closure in P. densata, but to both stomatal and non-stomatal limitations in its progenitors, as the parental species had increased intercellular CO₂ concentrations (C_i) under the stress. Significant decreases in chlorophyll fluorescence parameters were also observed in both parental species, but they varied little throughout the experiment in P. densata. Furthermore, the chlorophyll and carotenoid concentrations decreased significantly under the cold stress, while anthocyanin concentrations increased, and the anthocyanin concentration in P. densata was significantly higher than in either parental species at the end of the exposure. Finally, P. densata recovered more quickly than its parental species when the cold treatment ended. These results show that P. densata maintains a high photosynthetic rate and exhibits elevated PSII activity and anthocyanin levels under cold stress. These adaptations suggest that P. densata is more cold-tolerant than its parental species and may have been important for its colonization of high alpine habitats.     

彰武松、樟子松光合生产与蒸腾耗水特性

本文采用Li-6400光合测定系统对性成熟(18a)阶段彰武松(Pinus densiflora var.zhangwuensis)和樟子松(Pinus sylvestris var.mongolica)光合及蒸腾指标不同季节日变化进行了测定,并采用切枝蒸腾法对两个树种叶片气孔蒸腾和角质层蒸腾进行对比测定,评价了气孔开闭敏感性,探讨了两个树种光合生产与蒸腾耗水特性。结果表明：在同样生境条件下,彰武松比樟子松有较大的光合速率(Pn)和较小的蒸腾速率(Tr)。在5月和7月,彰武松的Pn和Tr日变化呈现明显双峰型,其Pn和Tr“午休”现象均主要受气孔限制;在10月呈单峰型。樟子松的Pn和Tr日变化在整个生长季均呈单峰型,而且,彰武松日光合量(DAP)均高于樟子松,是樟子松的163.4%(5月)、211.1%(7月)和183.6%(10月)。光响应曲线参数表明：在不同月份,彰武松最大光合速率(Pmax)均大于樟子松,且光饱和点(LSP)较高,光补偿点(LCP)较低。在任意被测时刻,彰武松气孔导度(Gs)和Tr都小于樟子松。彰武松具有较小气孔和角质层蒸腾速度,并且在同样干旱条件下,彰武松气孔下陷,其气孔的开闭反应更加敏感。彰武松水分利用效率(WUE)较高,约是樟子松的2.29倍。这些结果暗示,彰武松以其高的光合速率和低的蒸腾耗水特性,提高水分利用效率,以其敏感的气孔开闭机制和旱生叶片结构进而实现在干旱半干旱地区的速生特性。     

羊草叶片气体交换参数对温度和土壤水分的响应

 采用生长箱控制的方法研究了羊草(Leymus chinensis)幼苗叶片光合参数对5个温度和5个水分梯度的响应和适应。结果表明：轻度、中度土壤干旱并没有限制羊草叶片的生长,对气体交换参数亦无显著影响,反映了羊草幼苗对土壤水分胁迫的较高耐性。叶片生物量以26 ℃时最大,其它依次为23 ℃、20 ℃、29 ℃和32 ℃。温度升高使气孔导度和蒸腾速率增加, 却使光合速率和水分利用效率降低。水分和温度对叶片生物量、光合速率、气孔导度和蒸腾速率存在显著的交互作用,表明高温加强了干旱对叶片生长和气体交换的影响, 降低了羊草对土壤干旱的适应能力。高温和干旱的交互作用将显著减少我国半干旱地区草原的羊草生产力。     

The influence of water stress on the photosynthetic performance and stomatal behaviour of tree seedlings subjected to variation in temperature and irradiance

Summary Seedlings of Betula pendula Roth. and Gmelina arborea L. were subjected to variation in temperature and irradiance. The influence of a mild water-stressing treatment on the photosynthetic performance and stomatal behaviour of these plants was assessed. For both species, the shape of the relationships between irradiance and photosynthesis and temperature and photosynthesis resembled those reported for other species. The effect of water stress was to reduce the rate of photosynthesis, particularly at high temperatures. This was largely a function of a reduction in mesophyll conductance under these conditions. The optimum temperature for stomatal opening was significantly lower than the optimum temperature for photosynthesis, which was in turn lowered by the water stress treatment. The stomata of birch seedlings showed maximum opening at an intermediate temperature while the stomata of Gmelina generally exhibited a closing movement when leaf temperatures increased from 15° C. Mesophyll conductances of both species increased with increasing temperature.The physiological basis for the variation in photosynthetic performance and stomatal behaviour and the ecological significance of this variation are discussed.     

Photosynthesis of <Emphasis Type="Italic">Populus euphratica</Emphasis> in relation to groundwater depths and high temperature in arid environment,northwest China

The photosynthetic characterization of Populus euphratica and their response to increasing groundwater depth and temperature were analyzed based on net photosynthetic rate (P _N), stomatal conductance (g _s), intercellular CO₂ concentration (C _i), transpiration rate (E), water use efficiency (WUE) and stomatal limitation (L_s) measured by a portable gas-exchange system (LI-6400) in the lower reaches of the Tarim River. Light-response curves were constructed to obtain light-compensation and light-saturation points (LCP and LSP), maximum photosynthetic rates (P _max), quantum yields (AQY), and dark respiration rates (R _D). The growth condition of P. euphratica, soil moisture, and groundwater depth in the plots were analyzed by field investigation. The results showed that the growth condition and photosynthetic characterization of P. euphratica were closely related to groundwater depth. The rational groundwater depth for the normal growth and photosynthesis was 3–5 m, the stress groundwater depth for mild drought was more than 5 m, for moderate drought was more than 6 m, for severe drought was more than 7 m. However, P. euphratica could keep normal growth through a strong drought resistance depended on the stomatal limitation and osmotic adjustment when it faced mild or moderate drought stress, respectively, at a normal temperature (25°C). High temperature (40°C) significantly reduced P _N and drought stress exacerbated the damage of high temperature to the photosynthesis. Moreover, P. euphratica would prioritize the resistance of high temperature when it encountered the interaction between heat shock and water deficit through the stomata open unequally to improve the transpiration of leaves to dissipate overheating at the cost of low WUE, and then resist water stress through the osmotic adjustment or the stomatal limitation.     

Effects of Low Temperature on Photosynthesis in Flag Leaves of Rice (Oryza sativa L.)

After low temperature (16℃) treatment, the net photosynthetic rate, chlorophyll content and FBPase activity tended to decrease and ratio of chlorophyll a/b, stomatal resistance, sucrose and starch content tended to increase in rice flag leaves at heading stage. However, the Pi content and water potential did not show pronounced change. The flag leaf chloroplasts contained large starch grains after three days at low temperature. The recovery of net photosynthetic rate in the flag leaves which had recieved stress at 16℃ for three days and transferred to normal nature condition was gradually increased. It almost came up to the value of control after five days. However, the decrease in stomatal resistance was rapid. It was almost lowered to the value of control after one day. Under normal nature comdition for five days, the chlorophyll content and FBPase activity reached near to the value of control. Meanwhile, the ratio of chlorophyll a/b, the sucrose and starch content almost declined to the value of control. The large starch grain in flag leaf chloroplast also disappeared. According to the experimental results, we discussed the relationship between the above-mentioned various changes and net photosynthetic rate We suggested that the effect of low temperature on photosynthesis might be one of factors in yield-reduction of rice.     

低温胁迫下不同甘蔗品种(系)光合特性的变化及其与耐寒性的关系

以广西农科院甘蔗研究所自育的7个新材料和2个生产上的主栽品种为研究对象,在甘蔗苗期进行低温胁迫处理,研究了各品种(系)甘蔗形态特征的冷害指数、叶绿素含量及光合特性相关指标的变化及其光合特性相关指标与甘蔗抗寒性间的相关性。结果表明:随着低温胁迫处理时间的延长,冷害指数不断增大,但变化的大小与快慢因品种(系)不同表现不一样。各甘蔗品种(系)叶片叶绿素含量均随时间延长而降低。叶片净光合速率、气孔导度在低温处理与常温处理间具有显著差异。低温胁迫处理显著降低了各甘蔗品种(系)最大光化学效率(Fv/Fm)、PSⅡ实际光能转化效率ΦPSⅡ、光适应下PSⅡ反应中心的最大光能转化效率Fv′/Fm′、光化学猝灭系数qP、电子传递速率ETR,而显著提高了初始荧光Fo、稳态荧光Fs、非光化学猝灭系数qNP。相关性分析表明整个测定时期各指标间相关显著,Fv/Fm、Fv′/Fm′、ΦPSⅡ与冷害指数I之间的相关系数在0.800以上,Fv/Fm、Fv′/Fm′、ΦPSⅡ可以作为甘蔗品种(系)抗寒性鉴定的重要参考指标。