Effect of Elevated CO2 on the Photosynthesis, Growth and Water Relation of Brassica Species Under Moisture Stress

An attempt has been made to study the interactive effect of elevated CO₂ and moisture stress on photosynthesis, growth and water relations of Brassica species using open top chambers. It was observed that plants responded to elevated CO₂ significantly under moisture stress condition mitigating the adverse effects on photosynthesis and growth of Brassica species. Relatively drought susceptible species, viz. B. campestris and B. nigra , responded to elevated CC₂ markedly as compared to less sensitive B. carinata and B. juncea plants. The water status of plants significantly improved under elevated CO₂ concentration possibly by increasing stomatal resistance and/or by increased root growth.     

Characterization of CO2 Responsiveness in a Brassica oxycamp Interspecific Hybrid

A study of the characterization of CO₂ responsiveness in Brassica oxycamp and its parents Brassica oxyrrhina and Brassica campestris was done using open top chamber technology. The response of the X. B. oxycamp (hybrid) to elevated CO₂ was significantly positive in respect of photosynthesis and growth and similar to that of its parent B. campestris. X B. oxycamp and B. campestris with greater sink potential responded significantly, whereas B. oxyrrhina with a poor sink, did not respond to CO₂ enrichment. Photosynthetic changes at elevated CO₃ levels in the hybrid and parents are partially attributed to the CO₂ effects on stomatal conductance and chlorophyll fluorescence.     

土壤水分和CO2浓度增加对小麦、玉米、棉花蒸散、光合及生长的影响

通过在大型人工气候室内的试验、设计了350和700μl/L,两种C02浓度水平和高、中、低三种土壤水分处理,其土壤含水率范围分别为85%-100%, 65%-85%和45%-65%(占田间持水量的百分数),分析了土壤水分条件和大气CO2浓度增加的共同作用对小麦、玉米、棉花等作物蒸发蒸腾、光合速率、生长状况与干物质积累、水分利用效率的影响。     

Contribution of Leaf Photosynthesis towards Seed Yield in Brassica species

The effect of defoliation after flowering, when a considerable number of pods were already formed on yield components, was examined in four Brassica species. In B. campestris and B. juncea , a decrease in seed yield by defoliation was associated with a decrease in the number of pods per plant as seed number per pod and thousand-seed weight were not significantly affected by this treatment. In B. nigra , apart from decreasing the pod number per plant, defoliation also significantly decreased the thousand-seed weight, Defoliation significantly decreased both seed number per pod and thousand-seed weight apart from decreasing the number of pods per plant in B. carinata. The study indicated that in B. campestris and B. juncea , the role of leaf photosynthesis seemed to be restricted mainly to the formation of pods. On the other hand, in B. nigra and B. carinata it appeared that leaf photosynthesis also contributed towards seed development.     

Relationship Between Leaf Nitrogen and Photosynthetic Characteristics in Brassica juncea and B. campestris

The relationship between leaf nitrogen content (N) versus photosynthetic rate (PN) and other associated parameters was examined in Brassica juncea , cv. Pusa Bold and B campestris , cv. Pusa Kalyani. Leaf N, specific leaf weight (SLW), leaf area and PN were significantly higher in B. juncea , while the chlorophyll content was significantly lower compared to Brassica campestris. A significant positive correlation was obtained between leaf N content and photosynthetic rate in both species. Similarly, SLW was also positively related with leaf N content, Brassica juncea showed higher photosynthetic nitrogen use efficiency (PNUE) than B campestris. Leaf N and PNUE were negatively associated. This was attributed to a low investment of N in photosynthesis related reactions and/or partitioning of N towards compounds functionally unrelated to photosynthesis. This attribution is further supported by the negative relationship obtained between SLW and PNUE.     

水浸胁迫对超表达Sub1A油菜(Brassica napus)抗氧化能力的影响

环境中水分含量变化对于生长期油菜的产量和品质影响极大。国内外研究表明,异源表达Sub1A基因具有提高水涝条件下植物的抗逆性和恢复生长的潜能。本研究以组成型表达Sub1A基因的甘蓝型油菜作为实验材料,测试了其在水浸胁迫30 d内的生长速度和抗氧化水平。结果表明,超表达株系在地上部分和地下部分的生物量积累速率均显著高于野生型油菜,在胁迫早期尤为明显,表现出响应水浸胁迫的优良表型。同时,抗氧化酶(SOD,POD,CAT和GPX)活性和胁迫响应基因的表达变化也基本一致,呈现出胁迫早期强,随着处理时间增加呈逐渐降低的趋势。以上结果说明超表达Sub1A基因可能通过提高细胞的抗氧化酶活性、提高胁迫响应基因的表达水平提升抗水浸胁迫能力。本研究将为深入研究外源表达Sub1A基因提高油菜抗水浸胁迫提供依据,并为抗涝油菜新品种的开发提供前期基础。     

逐渐干旱对牡丹光合和荧光特性的影响

（研究目的） 研究逐渐干旱条件下牡丹光合指标及荧光特性变化。（方法）以胡红、洛阳红两种牡丹品种为试验材料,进行土壤逐渐干旱处理,从牡丹光合响应、气体交换、叶绿素荧光参数的变化来研究牡丹光合与荧光特性。（结果）随着土壤水分胁迫的加剧,叶片的净光合速率（Pn）和气孔导度（Gs）下降,胞间CO2浓度（Ci）升高,干旱降低牡丹净光合作用、限制气体交换。（结论）75%的土壤相对含水量最适合牡丹的生长,同时发现与干旱胁迫相比,水分过多更不利牡丹的生长。不同品种间比较发现,胡红比洛阳红更耐旱,适应性更广     

High Temperature Influence 14CO2 Assimilation and Allocation of 14C into Different Biochemical Fractions in the Leaves of Indian Mustard

Influence of high temperature stress on photosynthesis and allocation of carbon into different biochemical fractions in mature leaves of Indian mustard [ Brassica juncea (L) Czern] was investigated. Heat stress reduced ¹⁴CO₂ fixation and inhibited the translocation of carbon from the leaves. Allocation of ¹⁴C into starch and residue fractions was significantly lower in heat stressed plant leaves. Starch content was significantly reduced in heat stressed plants.     

大气O3浓度升高对玉米光合作用和籽粒品质的影响

利用开顶式气室研究了大气O3浓度升高对玉米（Zea mays L．）叶片光合作用、籽粒品质以及产量的影响。结果表明,整个生长季内,与对照相比,在高浓度O3（80nmol／mol）条件下,玉米叶片的净光合速率、气孔导度、蒸腾速率显著下降（P〈0．05）,而胞间CO2浓度先降低后升高并达到极显著水平（P〈0．01）,这说明使光合速率降低的主要因素由气孔限制逐渐转变为非气孔限制。与对照相比,高浓度O3处理植株叶绿素a、叶绿素b及叶绿素（a＋b）含量降低,叶绿素a／b值则先降低后升高。但是随着熏蒸时间的延长,高浓度O3处理植株的叶绿素a、叶绿素（a＋b）含量与叶绿素a／b值变化呈先升高后降低的趋势,与叶绿素b含量变化不同;O3浓度升高在一定程度上使玉米籽粒品质下降,其中蛋白质和淀粉含量降低,而粗脂肪和蛋脂总量略有升高;百粒重、穗粒数和穗粒重均显著低于对照（P〈0．05）,说明O3浓度升高降低了玉米的光合能力,籽粒品质受到影响,抑制了作物生长。     

不同水分胁迫对番茄生长的影响

番茄成苗后的生长对水分胁迫反应敏感，首先反映在茎的粗细，随着水分胁迫的减少，番茄的茎变粗，对株高和叶片数的影响的一段果以下的栽培反应不明显，水分胁迫使番茄的叶绿素含量增加，植物体内不势下降，气孔关闭，蒸腾减小，光合速率减弱，进而使产量降低，在合理用水的前提下要提高产量，三段果以下的番茄栽培应把定植后到果实膨大前这段时期的土壤水分胁迫控制在０．０４ＭＰａ左右。果实进入膨大期以后的土壤水分胁迫应控制在     

Effects of Single and Multifactor Treatments with Elevated Temperature,CO2 and Ozone on Oilseed Rape and Barley

We investigated the effect of elevated [CO₂], [O₃] and temperature on plant productivity and if these climate factors interacted with each other in multifactor treatments. The climate effects were studied in 14 different cultivars/lines of European spring oilseed rape (Brassica napus L.) and spring barley (Hordeum vulgare L.). Seven genotypes of each species were cultivated in six single‐ and multifactor treatments with ambient or elevated CO₂ (385 ppm and 700 ppm), O₃ (20 ppb and 60 ppb) and temperature (12/19 °C and 17/24 °C). Growth and production parameters were measured. Elevated CO₂ increased yield and biomass. Seed number increased by about 47 % in barley and by 26 % in oilseed rape, but in oilseed rape, the TSW was significantly decreased, possibly because of shortening of the seed filling period. Higher temperatures decreased yield and biomass significantly in both species. A significantly decreased yield and thousand grain weight was also seen in barley due to elevated O₃. The multifactor combination of elevated CO₂, O₃ and temperature showed a decrease in growth and production in the two species, though not statistically significant for all parameters. This trend suggests that the expected increase in the plant production in northern Europe, indicated by Intergovernmental Panel on Climate Change (IPCC) as a consequence of increased [CO₂] and temperature, may not hold, due to interactions between these abiotic factors.     

Drought Stress Effects on Seed Yield, Yield Attributes, Growth, Cell Membrane Stability and Gas Exchange of Synthesized Brassica napus L.

Drought stress effects on leaf gas exchange, cell membrane stability, seed yield and yield attributes of synthesized Brassica napus L. cv. Bangla kale and Bangla cabbage were compared. Drought stress treatments were imposed at early vegetative, late vegetative and flowering stages by withholding watering. Bangla cabbage produced greater pods/plant, larger seed size, greater total dry matter/plant, seeds/pot, and 17% greater yield than Bangla kale. The seed yield in plants stressed at early vegetative, late vegetative and flowering stages were 59, 74, 88% lower respectively, than watered plants. Drought stress reduced leaf photosynthesis by 67 to 97%. Bangla cabbage had 68% greater photosynthesis and 56% greater stomatal conductance than Bangla kale under stress at flowering stage. Leaf temperature was 1 to 2°C higher in stressed plants than watered plants. The cell membrane stability (CMS) increased up to 83% at flowering stage under stress compared to 21% under watered conditions. Although Bangla cabbage had high seed yield, yield attributes and photosynthesis under stressed conditions at flowering stage, its CMS values were lower than those of Bangla kale.     

Cytoplasm Influences the Photosynthetic Efficiency in Brassica carinata

Cytoplasmic effects on the photosynthesis was investigated in experimentally produced Brassica carinatas of reciprocal cytoplasmic origin. These are obtained by hybridizing B. nigra x B. oleracea var. italica ( B. carinata 226) and B. oleracea x B. nigra ( B. carinata 241). Natural B. carinata and the two parents viz. B. nigra and B. oleracea var. italica were also included in this study. It was observed that the rate of photosynthesis in B. carinata 226 with nigra cytoplasm, and natural B. carinata was higher than that of B. carinata 241 with oleracea cytoplasm. This was substantiated by the diurnal values of photosynthesis among these cultivars. The result indicated that the cytoplasm does affect the rate of photosynthesis in B. carinata and high photosynthetic efficiency in natural B. carinata was due to B. nigra maternal parent.     

干旱对大豆生理及产量影响的研究

干旱对农业生产影响巨大,开展干旱胁迫对大豆生理及产量影响的研究,将为干旱地区大豆生产提供理论依据。利用塑料整理箱进行了干旱胁迫对大豆光合生理、叶片抗氧化物酶和渗透调节物以及生物量、产量影响的研究,土壤水分为干旱(45%~55%的田间土壤最大持水量)和湿润(80%~100%的田间土壤最大持水量,CK)2个水平,进行了2年的试验研究。结果表明,干旱胁迫使大豆净光合速率、气孔导度、蒸腾速率均明显下降,使水分利用率增加;干旱胁迫对大豆叶片过氧化酶(POD)和超氧化物歧化酶(SOD)含量无显著影响;干旱使大豆叶片丙二醛(MDA)含量、还原糖含量和可溶性总糖含量增加25.00%,47.09%和47.16%。干旱胁迫使大豆株高、节数、茎粗明显下降。干旱使大豆地上部分生物量明显下降,其中2013年下降39.4%,2014年下降69.6%。干旱使大豆籽粒产量明显下降,2013,2014年分别下降46.9%和81.6%。干旱胁迫下,大豆叶片气孔导度显著下降,使CO2供应受到严重影响,降低叶片净光合速率。干旱胁迫还会使大豆细胞膜结构造成一定的破坏,影响植物正常的光合作用,使大豆光合代谢产物下降。虽然大豆可以通过渗透调节物质来保持细胞的水分,但干旱仍然抑制了植株的正常生长,使大豆生物量和产量下降。     

The Influence of Plant Water Stress on Net Photosynthesis and Yield of Sunflower (Helianthus annuus L.)

The effect of plant water stress on net photosynthesis, leaf growth, yield and yield-related components were investigated in a single experiment in order to determine in which way water deficits affect sunflower yields.
Sunflower plants, grown under controlled temperature regimes, were stressed during budding, anthesis and seed filling by withholding water until the leaf water potential reached -1600 and -2000 kPa. Leaf area of unstressed plants significantly exceeded that of plants under severe stress during all growth stages investigated. The CO₂ uptake rate per unit leaf area as well as the total uptake rate per plant, significantly diminished with stress, while this effect drastically increased during the reproductive phase of the plant. Although this resulted in significantly smaller heads and kernels, it did not affect the number of seeds borne in the inflorescence. Severe stress during anthesis and seed filling resulted in more empty kernels. Moderate and severe stress during budding significantly lowered both grain and oil yields while plants that experienced moderate stress during anthesis and seed filling significantly outyielded those under severe stress.     

水杨酸对铅胁迫下小白菜种子萌发和幼苗生长的缓解效应

以小白菜为材料,探讨了SA预处理对铅胁迫下小白菜幼苗生长的影响.结果表明,外源水杨酸预处理可以不同程度地缓解Pb对小白菜种子萌发和幼苗生长的毒害效应,种子萌发率上升,减少铅在幼苗体内的积累,促进株高和根长的增加;增加Pb胁迫下幼苗叶绿素含量和根系活力,减轻了Pb对小白菜幼苗的氧化胁迫程度,以0.5 μmol/L的sA处理效果最好.     

中国芸薹属植物的起源、演化与散布

芸薹属Brassica L植物在世界上大约有40余种，其中中国有15种。在此，就中国芸薹属植物的起源、演化和扩散问题进行了研究，结果表明：（1）芸薹属植物的起源。通过芸薹属与其外类群白花菜科Capparaceae形态特征的比较，将中国芸薹属植物划分为白菜组Sect Pekinensis、芥菜组Sect Juncea、甘蓝组Sect Oleracea三个类群，其中白菜组最原始、芥菜组较进化，甘蓝组进化程度最高；（2）芸薹属植物广泛分布于中国的长江、黄河流域及西部山区，但从其现代分布来看，多栽培于青藏高原及其周边地区，笔者认为以青藏高原为主体的西部高山、丘陵地区可能是中国芸薹属植物的分布中心区，并提出中国芸薹属植物是本土起源的，并非来源于地中海地区。（3）通过对中国芸薹属植物分布的分析，笔者推测中国芸薹属植物的散布可能有四条散布途径。第一条是由藏南河谷及横断山脉的北部向西沿青海东部的祁连山以及甘肃的河西走廊，新疆的天山一带，抵达塔里木盆地两侧山地。第二条是由藏南河谷及横断山脉地区向东北方向延伸，经中国甘肃东部、宁夏、陕西北部、山西、河北北部、内蒙古及东北的大、小兴安岭，沿黄河流域及东北三江流域分布。第三条是由藏南河谷及横断山脉地区向东南方向延伸，经四川、云南、重庆、沿长江流域分布，并延伸到广东、台湾一带，第四条是沿藏南河谷及横断山脉向南到达喜马拉雅山南北两侧的干旱河谷。     

硫素对不同基因型大豆皂甙含量的影响

为了探讨施硫量对不同基因型大豆皂甙含量的影响,寻找不同基因型大豆品种最佳施硫水平,以期提高大豆皂甙的含量,改善大豆品质。选用在黑龙江省种植面积较大的‘黑农48’（高蛋白）、‘黑农37’（中间型）和‘黑农44’（高油）3种大豆作为试验材料。采用盆栽种植,每个品种设4个处理组（即每kg土壤分别施单质硫0、0.02、0.04、0.06 g,即S1、S2、S3、S4）。采用有机溶剂提取法,对成熟大豆籽粒皂甙的含量进行测定。结果表明：‘黑农48’在S2条件下皂甙含量最高,‘黑农44’和‘黑农37’均在S3水平下皂甙含量最高,但‘黑农37’S1~S3水平表现不明显。过高硫素含量会降低大豆皂甙含量,不同基因型大豆对硫素敏感度不同,合理适量的施用硫肥能有效地提高大豆皂甙的含量。     

甘蓝型油菜抗旱性鉴定研究进展

甘蓝型油菜抗旱育种的最终目的是培育干旱条件下节水、高产的新品种。笔者通过形态及生长发育指标、生理生化指标(光合作用、渗透调节、抗氧化酶活性、内源激素、水分利用率等)、产量和品质指标、综合评价指标等对油菜抗旱性鉴定研究进行了回顾式分析,认为水分胁迫对油菜不同时期形态及生长发育具有重要影响。通过回顾式研究,对甘蓝型油菜抗旱性鉴定研究的现存问题进行分析,并对相关指标与技术展开讨论,以期为油菜抗旱性研究和生产提供参考。同时甘蓝型油菜抗旱性分子机制的阐明必然将油菜抗旱育种研究带入一个崭新的阶段。     

Influence of Soil Moisture and Fertilizer Potassium on the Vegetative Growth of Mungbean (Vigna radiata L. Wilczek) and Cowpea (Vigna unguiculata L. Walp)

Tropical food legumes are grown in a wide range of environments, and water stress is considered the principal environmental factor limiting growth and yield. Potassium fertilizer mitigates the impact of water stress in plants. However, the benefits of potassium in overcoming stress in tropical food legumes have not been investigated in comparative studies. The purpose of this study was to determine the benefits of potassium in overcoming water stress in mungbean and cowpea, two important tropical food legumes with different adaptabilities to soil moisture regimes. The experiment carried out under controlled conditions placed emphasis on vegetative growth and selected physiological parameters. The impact of potassium was different in the two legumes grown at optimal and suboptimal soil moisture. Potassium increased shoot growth of mungbean to a greater extent than in cowpea under suboptimal moisture conditions. The roots of cowpea showed a greater response to potassium fertilizer than in mungbean under suboptimal soil moisture. The plant water relations and photosynthetic rates of mungbean were improved to a greater extent by potassium under suboptimal soil moisture than those of cowpea. Although differences were observed in the responses of the vegetative growth of these species to moisture and potassium, in overall terms potassium promoted growth of both species when subject to suboptimal soil moisture. While field studies are required to validate the results, the application of potassium fertilizer can be considered a significant factor in overcoming soil moisture stress in these legumes commonly grown in tropical cropping systems.