不同二氧化碳浓度条件下红松和长白赤松幼苗根际土壤微生物数量研究

以连续5年不同CO₂浓度(开顶箱700μmol·mol^-1、500μmol·mol^-1、对照箱和裸地)处理的长白赤松和红松幼苗为研究对象,在2003年7～9月分别对幼苗根际土壤细菌、真菌、放线菌数量进行比较研究.结果表明,高浓度CO₂处理对长白赤松幼苗根际土壤细菌数量起显著的(P≤0.001)促进作用,对根际真菌和放线菌数量的促进作用却不明显;对红松来说,除8月份700μmol·mol^-1CO₂处理和7月份500μmol·mol^-1CO₂处理之外,在各月份中受高浓度CO₂处理的根际土壤细菌数量均较对照箱和裸地显著增多(P≤0.001),而根际土壤真菌数量变化除9月份(P≤0.001)外均不明显,放线菌数量受高浓度CO₂的影响亦不明显.     

日光温室冬季增施CO2对切花红掌光合作用及生长发育的影响

针对切花红掌日光温室冬季生产时CO₂亏缺严重的现象,以不增施CO₂为对照,研究了增施700、1000、1300 μmol·mol^-1浓度CO₂对切花红掌‘火焰’光合特性和生长发育的影响.结果表明: 增施60 d CO₂,红掌叶片的净光合速率、胞间CO₂浓度和水分利用效率均显著提高,且以1000 μmol·mol^-1处理的增幅最大;而气孔导度则较对照显著下降.增施CO₂后,红掌叶片的可溶性糖、淀粉和可溶性蛋白含量均较对照显著增加,佛焰苞大小、色泽、花茎长度等切花品质参数,以及叶片发育质量参数和花茎生长速率均有不同程度的提高,且均以1000 μmol·mol^-1浓度最佳.增施1000 μmol·mol^-1的CO₂可以有效促进日光温室切花红掌的冬季生产.     

日光温室冬季增施CO2对切花红掌光合作用及生长发育的影响

针对切花红掌日光温室冬季生产时CO₂亏缺严重的现象,以不增施CO₂为对照,研究了增施700、1000、1300 μmol·mol^-1浓度CO₂对切花红掌‘火焰’光合特性和生长发育的影响.结果表明: 增施60 d CO₂,红掌叶片的净光合速率、胞间CO₂浓度和水分利用效率均显著提高,且以1000 μmol·mol^-1处理的增幅最大;而气孔导度则较对照显著下降.增施CO₂后,红掌叶片的可溶性糖、淀粉和可溶性蛋白含量均较对照显著增加,佛焰苞大小、色泽、花茎长度等切花品质参数,以及叶片发育质量参数和花茎生长速率均有不同程度的提高,且均以1000 μmol·mol^-1浓度最佳.增施1000 μmol·mol^-1的CO₂可以有效促进日光温室切花红掌的冬季生产.     

大棚瓠瓜CO2加富的生理生态效应

春季对大棚瓠瓜增施CO₂,可促进植株的生长发育.株高、茎粗增幅分别达到3.90%～19.48%和11.58%～27.37%,叶片厚度及叶面积也分别增加38.46%～69.23%和26.09%～49.38%;第一雌花着生节位平均降低2.6～4.0节.平均单果重增加4.05%～19.62%,产量提高8.65%～19.47%.在1000μmol·mol^-1范围内,CO₂浓度每增加100μmol·mol^-1,单果重和产量分别增加31.97g和68.39kg·667m^-2;第一雌花着生节位降低0.35节.在1000μmol·mol^-1浓度下,瓤瓜光合速率和羧化速率均达最高值.春季大棚瓠瓜CO₂适宜施用浓度为1000μmol·mol^-1左右.     

大气CO2和O3浓度升高对水稻根际土壤胞外酶活性的影响

大气二氧化碳(CO₂)和臭氧(O₃)浓度升高是全球气候变化的主要特征之一。土壤胞外酶作为维持土壤生态系统服务功能的重要参与者，其活性对于大气CO₂和O₃浓度升高的响应特征及驱动机制研究，以及应对并缓解未来全球气候变化具有重要意义。本研究采用开顶式气室(OTCs)分别模拟大气CO₂浓度升高(环境大气+200μmol·mol^-1,eCO₂)、大气O₃浓度升高(环境大气+0.04μmol·mol^-1,eO₃)及其交互处理(环境大气+200μmol·mol^-1 CO₂+0.04μmol·mol^-1 O₃,eCO₂+eO₃),探究水稻根际土壤胞外酶活性对大气CO₂和O₃浓度升高的响应。结果表明：与对照(环境...     

红松幼苗对CO2浓度升高的生理生态反应

研究了用开顶箱控制CO₂浓度在500和700μmol·mol^-1左右时红松幼苗的生理生态反应.结果表明,高浓度CO₂(500、700μmol·mol^-1CO₂)和对照(对照开顶箱、裸地)条件下,红松幼苗的净光合速率与气孔导度之间的变化不同.红松幼苗在500μmol·mol^-1CO₂条件下,RuBPcase活性最高,呈现光合上调反应,日平均净光合速率最大,叶绿素及可溶性糖含量最高;而生长在700μmol·mol^-1CO₂的红松幼苗呈现光合下调反应,光合作用明显低于对照植株,其酶活性及物质含量均最低.     

水稻叶片光合作用对开放式空气CO2浓度增高(FACE)的响应与适应

利用便携式光合气体分析系统(LI-6400),比较测定了高CO₂浓度(FACE,free-airCO₂enrichment)和普通空气CO₂浓度下生长的水稻叶片的净光合速率、水分利用率、表观量子效率和RuBP羧化效率等光合参数.在各自生长CO₂浓度(380vs580μmol·mol^-1)下测定时,高CO₂浓度(580μmol·mol^-1)下生长的水稻叶片的净光合速率、碳同化的表观量子效率和水分利用率明显高于普通空气(380μmol·mol^-1)下生长的水稻叶片.但是,随着FACE处理时间的延长,高CO₂浓度对净光合速率的促进作用逐渐减小.在相同CO₂浓度下测定时,FACE条件下生长的水稻叶片净光合速率和羧化效率明显比普通空气下生长的对照低.尽管高CO₂浓度下生长的水稻叶片的气孔导度明显低于普通空气中生长的水稻叶片,但两者胞间CO₂浓度差异不显著,因此高CO₂浓度下生长的水稻叶片光合下调似乎不是由气孔导度降低造成的.     

CO2浓度升高对木荷幼苗光合特征的影响

IPCC(Intergovernmental Panel on Climate Change)报告预测,到2100年CO₂浓度会出现430～480、580～720、720～1000和>1000μmol·mol^-1 4种不同情景,而目前同时探究所有CO₂情景下植物响应情况的研究很少。本试验利用开顶式气室分别探究自然大气浓度(约400μmol·mol^-1)、550、750和1000μmol·mol^-1 4个CO₂水平在生长季内对一年生木荷(Schima superba)幼苗气体交换参数、光合色素含量及生物量的影响。结果表明：熏气期间,550、750和1000μmol·mol^-1浓度下木荷幼苗净光合速率分别平均提升32.7%、66.7%、82.7%,胞间CO₂浓度分别平均增加60.3%、126.2%、223.9%,而高浓度CO₂对净光合速率的提升作用随着熏气时间延长,可能受叶片氮含量减少等非...     

氮素添加和CO2浓度升高对白羊草根际和非根际土壤水溶性有机碳、氮的影响

采用盆栽控制试验对黄土丘陵区白羊草在不同CO₂浓度(400和800 μmol·mol^-1)和施氮水平(0、2.5、5.0 g N·m^-2·a^-1)条件下根际和非根际土壤水溶性有机碳(DOC)和水溶性有机氮(DON)的变化特征进行研究.结果表明: CO₂浓度升高对白羊草根际和非根际土壤DOC、水溶性总氮(DTN)、DON、水溶性铵态氮(NH₄⁺-N)、水溶性硝态氮(NO₃^--N)含量均无显著影响.施氮显著提高了根际和非根际土壤DTN、NO₃^--N含量和根际土壤DON含量,显著降低了根际土壤DOC/DON.在各处理条件下,根际土壤DTN、NO₃^--N和DON含量均显著低于非根际土壤,根际土壤DOC/DON显著高于非根际土壤.短期CO₂浓度升高对黄土丘陵区土壤水溶性有机碳、氮含量无显著影响,而氮沉降的增加在一定程度上改善了土壤中水溶性氮素缺乏的状况,但并不足以满足植被对水溶性氮素的需求.     

氮素添加和CO2浓度升高对白羊草根际和非根际土壤水溶性有机碳、氮的影响

采用盆栽控制试验对黄土丘陵区白羊草在不同CO₂浓度(400和800 μmol·mol^-1)和施氮水平(0、2.5、5.0 g N·m^-2·a^-1)条件下根际和非根际土壤水溶性有机碳(DOC)和水溶性有机氮(DON)的变化特征进行研究.结果表明: CO₂浓度升高对白羊草根际和非根际土壤DOC、水溶性总氮(DTN)、DON、水溶性铵态氮(NH₄⁺-N)、水溶性硝态氮(NO₃^--N)含量均无显著影响.施氮显著提高了根际和非根际土壤DTN、NO₃^--N含量和根际土壤DON含量,显著降低了根际土壤DOC/DON.在各处理条件下,根际土壤DTN、NO₃^--N和DON含量均显著低于非根际土壤,根际土壤DOC/DON显著高于非根际土壤.短期CO₂浓度升高对黄土丘陵区土壤水溶性有机碳、氮含量无显著影响,而氮沉降的增加在一定程度上改善了土壤中水溶性氮素缺乏的状况,但并不足以满足植被对水溶性氮素的需求.     

Influence of changes in daylength and carbon dioxide on the growth of potato

Potatoes (Solanum tuberosum L.) are highly productive in mid- to high-latitude areas where photoperiods change significantly throughout the growing season. To study the effects of changes in photoperiod on growth and tuber development of potato cv. Denali, plants were grown for 112 d with 400 micromol m-2 s-1 photosynthetic photon flux (PPF) under a 12-h photoperiod (short days, SD), a 24-h photoperiod (long days, LD), and combinations where plants were moved between the two photoperiods 28, 56, or 84 d after planting. Plants given LD throughout growth received the greatest total daily PPF and produced the greatest tuber yields. At similar levels of total PPF, plants given SD followed by LD yielded greater tuber dry mass (DM) than plants given LD followed by SD. Stem DM per plant, leaf DM, and total plant DM all increased with an increasing proportion of LD and increasing daily PPF, regardless of the daylength sequence. When studies were repeated, but at an enriched (1000 micromol mol-1) CO2 concentration, overall growth trends were similar, with high CO2 resulting in greater stem length, stem DM, leaf DM, and total plant DM; but high CO2 did not increase tuber DM.     

高浓度二氧化碳对百合生长和两种化感物质的影响

在大棚栽培条件下,研究不同CO₂浓度（600、800、1 000 μmol·mol^-1）对亚洲型黄花多头切花百合的影响.结果表明,CO₂浓度为600 μmol·mol^-1时,切花百合维持较高的Pn,在CO₂浓度为600～1 000 μmol·mol^-1时并持续45 d,百合并未出现明显的光合作用下调,这与新生子球对高CO₂浓度下的百合光合适应性具有一定调节能力有关.CO₂浓度为600 μmol·mol^-1时,能提高百合切花0.57个茎高等级,对显色花蕾增长有正效应.不同CO₂浓度对百合叶片中的多酚类和类黄酮含量影响不同,CO₂浓度为600和800 μmol·mol^-1时,能明显提高多酚类和类黄酮含量,植株也未出现叶枯病病株,这与适宜的高CO₂浓度对Pn及碳水化合物的形成和转化以及化感物质与提高百合自身抗病性有关.在试验浓度范围内,CO₂浓度为600 μmol·mol^-1时最有利于百合叶片多酚类和类黄酮含量的提高.     

StGA2ox1 is induced prior to stolon swelling and controls GA levels during potato tuber development

The formation and growth of a potato ( Solanum tuberosum ) tuber is a complex process regulated by different environmental signals and plant hormones. In particular, the action of gibberellins (GAs) has been implicated in different aspects of potato tuber formation. Here we report on the isolation and functional analysis of a potato GA 2-oxidase gene ( StGA2ox1 ) and its role in tuber formation. StGA2ox1 is upregulated during the early stages of potato tuber development prior to visible swelling and is predominantly expressed in the subapical region of the stolon and growing tuber. 35S-over-expression transformants exhibit a dwarf phenotype, reduced stolon growth and earlier in vitro tuberization. Transgenic plants with reduced expression levels of StGA2ox1 showed normal plant growth, an altered stolon swelling phenotype and delayed in vitro tuberization. Tubers of the StGA2ox1 suppression clones contain increased levels of GA₂₀, indicating altered GA metabolism. We propose a role for StGA2ox1 in early tuber initiation by modifying GA levels in the subapical stolon region at the onset of tuberization, thereby facilitating normal tuber development and growth.     

Effects of elevated CO2 on the capacity for photosynthesis of a single leaf and a whole plant, and on growth in a radish

The atmospheric concentration of CO2 will probably rise to about 700 micromol mol(-1) by the end of this century. The effects of elevated growth CO2 on photosynthesis are still not fully understood. Effects of elevated growth CO2 on the capacity for photosynthesis of a single leaf and a whole plant were investigated with the radish cultivar White Cherish. The plants were grown under ambient ( approximately 400 micromol mol(-1)) or elevated CO2 ( approximately 750 micromol mol(-1)). The rates of net photosynthesis per leaf area with a whole plant and a single leaf of plants of various ages (15-26 d after planting) were measured under ambient and elevated CO2. The rates of photosynthesis were increased by 20-28% by elevated CO2. There was no effect of elevated growth CO2 on the rate of photosynthesis, clearly indicating no downward acclimation of photosynthesis to elevated CO2. Elevated CO2 increased dry weight accumulation by >27%. The effect of elevated CO2 on other growth characteristics will also be shown.     

Comparison of axillary bud growth and patatin accumulation in potato leaf cuttings as assays for tuber induction

Single-node leaf cuttings from potatoes (Solanum tuberosum L.) cvs. Norland, Superior, Norchip, and Kennebec, were used to assess tuber induction in plants grown under 12, 16, and 20 h daily irradiation (400 micromol s-1 m-2 PPF). Leaf cuttings were taken from plants at four, six and 15 weeks after planting and cultured for 14 d in sand trays in humid environments. Tuber induction was determined by visually rating the type of growth at the attached axillary bud, and by measuring the accumulation of the major tuber protein, patatin, in the base of the petioles. Axillary buds from leaf cuttings of plants grown under the 12 h photoperiod consistently formed round, sessile tubers at the axils for all four cultivars at all harvests. Buds from cuttings of plants grown under the 16 and 20 h photoperiods exhibited mixed tuber, stolon, and leafy shoot growth. Patatin accumulation was highest in petioles of cuttings taken from 12 h plants for all cultivars at all harvests, with levels in 16 and 20 h cuttings approx. one-half that of the 12 h cuttings. Trends, both in visual ratings of axillary buds and in petiole patatin accumulation, followed the harvest index (ratio of tuber to total plant dry matter), suggesting that either method is an acceptable assay for tuber induction in the potato.     

热带季节雨林冠层树种绒毛番龙眼的光合生理生态特性

采用Li-6400便携式光合作用测定仪,对西双版纳热带季节雨林冠层树种绒毛番龙眼成树树冠上、中、下3层叶片进行了测定,分析西双版纳热带季节雨林冠层树木的光合作用.结果表明,绒毛番龙眼成树具有喜光的光合特性,光饱和点较高(1 000～1 500 μmol·m^-2·s^-1),而光补偿点较低(7.7～15.3 μmol·m^-2·s^-1),对光环境有较强的适应和调节能力,光合有效辐射是影响绒毛番龙眼光合日进程的关键因子;12月,叶片处于成熟期,生长良好,光合能力较强,树冠上层净光合速率（P_n）日变化为单峰型,最大净光合速率（A_max）约为8.9 μmol CO₂·m^-2·s^-1;4月处于新老树叶更替期,光合能力下降,树冠上层P_n日变化为双峰型,中午出现“午休”现象,树冠上层A_max约为4.3 μmol CO₂·m^-2·s^-1;7月上、中层叶片P_n为单峰型,下层出现“午休”.如人为使CO₂浓度在短期内迅速升高,则绒毛番龙眼的P_n会增加,而气孔导度和蒸腾速率降低;CO₂浓度从400 μmol·mol^-1升高到800 μmol·mol^-1时,干季水分利用效率（WUE）提高约50%～100％,雨季WUE较低.     

Rhizobacteria that produce auxins and contain 1‐amino‐cyclopropane‐1‐carboxylic acid deaminase decrease amino acid concentrations in the rhizosphere and improve growth and yield of well‐watered and water‐limited potato (Solanum tuberosum)

Plant‐growth‐promoting rhizobacteria (PGPR) utilise amino acids exuded from plant root systems, but hitherto there have been no direct measurements of rhizosphere concentrations of the amino acid 1‐amino‐cyclopropane‐1‐carboxylic acid (ACC) following inoculation with PGPR containing the enzyme ACC deaminase. When introduced to the rhizosphere of two potato (Solanum tuberosum) cultivars (cv. Swift and cv. Nevsky), various ACC deaminase containing rhizobacteria (Achromobacter xylosoxidans Cm4, Pseudomonas oryzihabitans Ep4 and Variovorax paradoxus 5C‐2) not only decreased rhizosphere ACC concentrations but also decreased concentrations of several proteinogenic amino acids (glutamic acid, histidine, isoleucine, leucine, phenylalanine, serine, threonine, tryptophan, tyrosine, valine). These effects were not always correlated with the ability of the bacteria to metabolise these compounds in vitro, suggesting bacterial mediation of root amino acid exudation. All rhizobacteria showed similar root colonisation following inoculation of sand cultures, thus species differences in amino acid utilisation profiles apparently did not confer any selective advantage in the potato rhizosphere. Rhizobacterial inoculation increased root biomass (by up to 50%) and tuber yield (by up to 40%) in pot trials, and tuber yield (by up to 27%) in field experiments, especially when plants were grown under water‐limited conditions. Nevertheless, inoculated and control plants showed similar leaf water relations, indicating that alternative mechanisms (regulation of phytohormone balance) were responsible for growth promotion. Rhizobacteria generally increased tuber number more than individual tuber weight, suggesting that accelerated vegetative development was responsible for increased yield.     

Tissue distribution and change in potato starch phosphorylase mRNA levels in wounded tissue and sprouting tubers.

Starch phosphorylase has been cloned from a lambda gt10 cDNA library of potato tuber mRNA. Selected recombinants have been used to demonstrate that phosphorylase mRNA is most abundant in tubers but is also detectable in stolon, root, stem and leaf tissue. The level of phosphorylase mRNA was greatly reduced in wounded stem and tuber tissue. The wounding-induced decrease in phosphorylase mRNA levels is not reversed in the presence of sucrose or mannitol. Regional differences are described in the levels of phosphorylase and patatin mRNA in different parts of the tuber and in the shoot of sprouting potatoes.     

二氧化碳和臭氧浓度升高对春小麦生长及次生代谢的影响

通过开顶式气室(OTCs)研究了OTC对照（自然CO₂浓度约342 μmol·mol^-1,O₃浓度约30 nmol·mol^-1）、高浓度CO₂（550 μmol·mol^-1）、高浓度O₃（浓度为80 nmol·mol^-1）及其交互作用（CO₂ 550 μmol ·mol^-1,O₃ 80 nmol·mol^-1）对春小麦不同发育时期生物量、总酚量、黄酮含量及成熟期产量性状的影响.结果表明：CO₂浓度增加条件下,春小麦生物量和产量性状都显著高于OTC对照（P<0.05）;而O₃浓度升高条件下,小麦生物量降低,株高、穗长、穗粒质量及千粒重也显著低于对照;CO₂和O₃交互作用下各项指标处于二者之间.说明CO₂可以缓解O₃对小麦的负效应,而O₃对CO₂的正效应具有削弱作用,但二者的作用并非简单的叠加.CO₂、O₃浓度增加及其交互作用显著增加了春小麦叶片中的总酚含量,其中两者交互作用的效应更大,但在小麦生长后期,总酚含量增加量比对照有所降低.在小麦生长前期,各处理总黄酮含量均低于对照;而在成熟期,各处理都显著高于对照.