长期水淹对枫杨幼苗光合生理和叶绿素荧光特性的影响

为阐明枫杨对三峡库区消落区土壤不同含水量的适应机理,模拟三峡库区消落区土壤水分变化特征,设置了常规土壤水分(T1)、土壤水分饱和(T2)及根部水淹(T3)3个不同条件处理组,研究了枫杨当年实生幼苗的光合色素含量、光合生理和叶绿素荧光特性.研究结果发现:经过1 a水淹后,土壤不同含水量对枫杨幼苗光合色素、气体交换参数、资源利用效率和叶绿素荧光参数有不同的影响,其中T2、T3的气孔导度(Gs)、蒸腾速率(Tr)、胞间CO_2浓度(Ci)和水分利用效率(WUE)与对照组T1相比没有显著变化;而其净光合速率(Pn)、光能利用效率(LUE)、CO_2利用效率(CUE)显著下降(p＜0.05),但T3组枫杨幼苗仍然具有较高的Pn,LUE,CUE;随着水淹强度的增大,枫杨幼苗的PSⅡ最大光化学效率(F_v/F_m)、PSⅡ光化学的量子效率(ΦPSⅡ)和光化学淬灭(qP)逐渐降低,非光化学淬灭(NPQ)逐渐升高.研究证实枫杨幼苗在经过长达1 a水淹后,仍然表现出较高的光合能力,是一种可以用于三峡库区消落区植被构建的优良植物物种.

Abstract：

Three water treatments, T1 (normal growth condition), T2 (soil water saturation), T3 (the root-distributed soil layer being completely submerged) were made in a simulation experiment to determine the photosynthetic characteristics and chlorophyll fluorescence parameters of Pterocarya stenoptera seedlings and to study the adaptation of P. stenoptera to the soil moisture conditions in the hydro-fluctuation belt of the Three Gorges Reservoir Area. Differences were found after 1 year's flooding among the three treatments in content of photosynthetic pigments, leaf gas exchange parameters, apparent resource use efficiency and chlorophyll fluorescence parameters of P. stenoptera. Stomatal conductance (Gs), transpiration rate (Tr), intercellular CO_2 concentration (Ci) and the water use efficiency (WUE) of the plants in T2 and T3 treatments did not decrease significantly compared to those in the control treatment (T1). Net photosynthetic rate (Pn), light use efficiency (LUE) and CO_2 use efficiency(CUE) of the plants in T2 and T3 were significantly lower than those in control plants(p＜0.05), but the plants in T3 still had relatively high Pn, LUE and CUE. With increasing flooding intensity, the potential efficiency of primary conversion flight energy of PS Ⅱ (F_v/F_m), quantum yield of PS Ⅱ photochemistry (ΦPS Ⅱ ) and photochemical quenching coefficient (qP) of P. stenoptera seedlings decreased and non-photochemical quenching coefficient (NPQ) increased. These results indicated that P. stenoptera is a promising tree species for revegetation in the hydro-fluctuation belt of the Three Gorges Reservoir Area since its seedlings maintained considerably high Pn after 1 year's flooding.     

Effects of light intensity on photosynthesis and photoprotective mechanisms in apple under progressive drought

The effects of light intensity on photosynthesis and photoprotective mechanisms under progressive drought were studied on apple trees(Malus domestica Borkh.) Fuji. The potted trees were exposed to drought stress for 12 days and different light conditions(100, 60 and 25% sunlight). During the progressive drought, the relative water content(RWC) in leaf declined and was faster in full light than in 60 and 25% sunlight. However, the decrease in the net photosynthetic rate(Pn), stomatal conductance(Gs) and Rubisco activity were slower under 100% sunlight condition than other light conditions. After the 6 days of drought, the maximum PSII quantum yield(Fv/Fm), the capacity of electrons move beyond Q-A(1–VJ) and electron move from intersystem to PSI acceptor side(1–VI)/(1–VJ) decreased, with greater decline extent in brighter light. While RWCs were 75%, the variations in different light intensities of Gs and Rubisco activity at identical RWC, suggested the direct effects of light. While the little difference in the state of photosynthetic electron transport chain among tested light intensities indicates the results of faster water loss rate of light. Our results also demonstrated that the enhancement the de-epoxidations of xanthophyll cycle, activities of ascorbate peroxidase(APX) and catalase(CAT) were directly regulated by light intensity. While the higher photorespiration rate(Pr) under stronger light condition was mainly caused by faster water loss rate of light.     

Effects of Water Stress on Photosynthesis and Fluorescence Characteristics in Peony

[Objective] Study on the photosynthesis and fluorescence characteristics in peony under water stress. [Method] The two peony varieties Huhong and Luoyanghong were treated by different water stress for determining the photosynthesis and fluorescence characteristics. [Result] With the aggravation of water stress,the net photosynthetic rate (Pn) and stomatal conductance (Gs) decreased,while the intercellular CO2 concentration (Ci) increased. Drought could decrease Pn,constrain gas exchange and change the daily photosynthesis. Fo of peony leaf increased and Fv/Fm decreased under water stress especially water logging,causing the inactivation of the PS II reaction center,and the chlorophyll fluorescence characters gradually recovered until afternoon. [Conclusion] The 75% soil relative water content (SRWC) is the best condition for growth of peony. Compared with drought,water logging is more unfit for the growth of peony. For the two varieties,Huhong assumed more tolerance to drought,accordingly more adaptability.     

水分胁迫对牡丹光合和荧光特性的影响(英文)

[Objective] Study on the photosynthesis and fluorescence characteristics in peony under water stress. [Method] The two peony varieties Huhong and Luoyanghong were treated by different water stress for determining the photosynthesis and fluorescence characteristics. [Result] With the aggravation of water stress,the net photosynthetic rate (Pn) and stomatal conductance (Gs) decreased,while the intercellular CO2 concentration (Ci) increased. Drought could decrease Pn,constrain gas exchange and change the daily photosynthesis. Fo of peony leaf increased and Fv/Fm decreased under water stress especially water logging,causing the inactivation of the PS II reaction center,and the chlorophyll fluorescence characters gradually recovered until afternoon. [Conclusion] The 75% soil relative water content (SRWC) is the best condition for growth of peony. Compared with drought,water logging is more unfit for the growth of peony. For the two varieties,Huhong assumed more tolerance to drought,accordingly more adaptability.     

Response and adaptation to the accumulation and distribution of photosynthetic product in peanut under salt stress

To clarify the response and adaptability of peanut under salt stress, Huayu 25 was used as the material, and non-salt stress(CK), 0.15% salt stress(S1), and 0.3% salt stress(S2) were applied as three treatments. The study analysed the effects of salt stress on photosynthetic characteristics, photosynthetic substances accumulation and distribution as well as the ecological adaptability of peanuts. The results showed that net photosynthetic rate(Pn), SPAD value, leaf area, and peanut yield were reduced under salt stress. Pn in CK was 13.71 and 28.72% higher than that in S1 and S2 at the 50 th day after planting, respectively. At the same growth period, the SPAD value among treatments was ranked as follows: CKS1S2. The 100-pod mass, 100-kernel mass, kernel rate to pod, and pod mass per plant were reduced under salt stress, and the trend was CKS1S2. The distribution proportion of dry matter in different organs of peanut plant was changed to adapt to such stress. Roots under salt stress intensively distributed in a 0–40 cm soil layer for salt resistance. Dry mass proportion in stems and pods increased during the vegetative stage and early period of reproductive stage, respectively. The maximum growth rates of the pod volume, pod dry weight, and seed kernel dry weight all declined, and the pod and kernel volume at harvest were reduced, improving the seed plumpness under salt stress. This finding could be useful in growing peanut in saline soil.     

外源牛磺酸处理对枸杞幼苗生理特性的影响(英文)

[Objective] The study was to investigate the relationship between taurine and physiological activities of Lyium bararum seedlings. [Method] Through applying different concentrations of taurine(0, 10, 100, 500, 1 000, 5 000 mg/L), the photosynthetic rate(Pn), stomatal conductance(Gs), and the activities of membrane protective enzymes superoxide dismutase(SOD) and peroxidase (POD) in the treated L. bararum seedlings were measured. [Result] Treatment of proper taurine concentration could to some extent enhance Pn and increase the POD and SOD activities, and meanwhile decreased the Gs and MDA content. And the optimum application amount of taurine was determined to be 500 mg/L. [Conclusion] Proper concentration of taurine has protective effects on the cell membrane of L. bararum seedlings.     

Effects of progressive drought on photosynthesis and partitioning of absorbed light in apple trees

To understand how drought stress affects CO2 assimilation and energy partitioning in apple(Malus domestica Borkh.), we investigated photosynthesis and photo-protective mechanisms when irrigation was withheld from potted Fuji trees. As the drought progressing, soil relative water content(SRWC) decreased from 87 to 24% in 15 d; this combined the decreasing in leaf relative water content(LRWC), net photosynthesis rate(P n) and stomatal conductance(G s). However, the concentrations of chlorophylls(Chl) remained unchanged while P n values were declining. Photochemistry reactions were slightly down-regulated only under severe drought. Rubisco activity was significantly decreased as drought conditions became more severe. The actual efficiency of photosystem II(ΦPSII) was diminished as drought became more intense. Consequently, xanthophyll-regulated dissipation of thermal energy was greatly enhanced. Simultaneously, the ratio of ΦPSII to the quantum yield of carbon metabolism, which is measured under non-photorespiratory conditions, increased in parallel with drought severity. Our results indicate that, under progressive drought stress, the reduction in photosynthesis in apple leaves can be attributed primarily to stomatal limitations and the inhibited capacity for CO2 fixation. Xanthophyll cycle-dependent thermal dissipation and the Mehler reaction are the most important pathways for dispersing excess energy from apple leaves during periods of drought stress.     

花期干旱胁迫对籼稻近等基因系水分和光合生理的影响

【Objective】An indica near-isogenic rice lines were treated with drought stress at flowering stage to study water and photosynthetic physiology changes of flag leaf. By analyzing the relationships among agronomic phenotype characters, water and photosynthetic physiology changes and fertility of rice, the authors try to accumulate data for drought tolerance evaluation of rice.【Method】The rice materials were suffered with drought stress begin from heading of main shoot for 15 days, water and photosynthetic physiology parameters were measured after treatment.【Result】The results showed that the indica near-isogenic rice represented various drought tolerance, and there was no correlation between drought tolerance and agronomic phenotype characters, neither with physiological activities of rice under well watered condition. However, under drought stress at flowering stage, the correlation coefficient between drought resistance indexes and changes of water content of flag leaf, water potential of flag leaf, stomatal conductance of flag leaf were 0.614**, 0.514** and 0.541**, respectively. This indicates that rice drought tolerance has a correlation with changes of water content, water potential and stomatal conductance. In addition, except the correlation coefficient between drought resistance indexes and changes of Fv/Fm of flag leaf (0.470*), there was no correlation between rice drought tolerance and photosynthetic physiology.【Conclusion】In summery, the changes of water physiology parameters could be used as indicators for screening rice with drought tolerance.     

Efficiency of seed bio-priming technique for healthy mungbean productivity under terminal drought stress

Recently, drought-induced damaging impact in reducing the crop growth and development is drastically ranked at the top under various abiotic stresses. And especially water stress at the reproductive growth stages termed as terminal drought has become a severe threat for mungbean productivity. To mitigate the drought stress condition, "bio-priming" has emerged as a newly agronomic and sustainable technique in improving the mungbean production. A 2-year field study during Kharif season 2017–2018 was conducted to investigate the efficacy of rhizobacteria seed priming in mungbean(AZRI mung-06), at Agronomic Research Area, Department of Agronomy, Bahauddin Zakariya University, Multan, Pakistan. The experiment comprised two factors containing F_A(seed treatments, control(dry seeds), hydro-priming, silicon(Si)-priming, and bio-priming(mixture strains of Pseudomonas fluorescens+Rhizobium phaseoli)) and F_B(irrigation water-regimes at various growth stages including leaf formation(L), stem elongation(S)+flowering(F)+pod formation(P) containing treatments are normal irrigation(I_(L+S+F+P)) and terminal drought stress(I_(F+P))). All the treatments were arranged in randomized complete block design under factorial design and were replicated thrice. Results indicated that the exposure of drought stress at flowering and pod formation stages hampered the morpho-physiological growth and yield of mungbean. Nevertheless, seed priming treatments particularly bio-priming were effective in alleviating the detrimental effects of drought stress. Bio-priming significantly increased the yield and yield components(seeds/plant, 1 000-grain weight and harvest index) of mungbean and regulated the activities/levels of antioxidants(superoxide dismutase, catalase, peroxidase, ascorbic acid, and total phenolics) under drought stress. Compared with the control, bio-priming increased the seed yield of mungbean by 8–12% under normal as well as drought stress conditions during both years of study. Bio-priming also improved the nutrient uptake behavior followed by Si-and hydro-priming treatments under terminal drought stress. The study emphasized the effectiveness of bio-priming as dual seed treatment method may be helpful for vigorous germination of mungbean production along with plant tolerance against terminal drought stress. Among the various treatments, plants treated with bio-priming technique compensated the grain yield due to having strong antioxidant defense system and better nutrient uptake behaviour under terminal drought stress. Economic analysis also concluded that bio-priming is the easiest, cost-effective, friendly, and sustainable approach for the maximization of the mungbean production.     

The effect of ozone and drought on the photosynthetic performance of canola

Canola plants were fumigated in open-top chambers with ozone(O_3)(120 ppb)under well-watered(WW)and water-stressed(WS)conditions for 4 weeks.Non-fumigated plants were also studied to facilitate comparison between treatments for the same week and over time.Therefore,the treatments were:WW,WW-O_3,WS and WS-O_3.The fast chlorophyll a fluorescence transients OJIP for the four treatments emitted upon illumination of dark-adapted leaves were measured after week 1,2,3,4 and analysed by the JIP-test to evaluate the resulting changes in photosynthetic performance.Ozone fumigation led to a decline of total performance index(PI_(total))in well-watered plants.The effect of O_3 was minor under drought conditions,as revealed by a decrease of PI_(total) by 3%.The PI_(total) decreased as the treatment was prolonged,due to leaf ageing for all cases and the decline was more pronounced under WW-O_3.Taking the average of all weeks,WW had the highest PI_(total )and the lowest WW-O_3(decrease by 27%),while in WS and WS-O_3,it was lower than WW(14 and 17%,respectively).We found that the absorption(ABS)/reaction centre(RC)increases,while the maximum quantum yield of primary photochemistry(φ_(Po))undergoes slight changes,and trapping(TR_0)/RC closely followed the increase in ABS/RC.This indicates that O_3and drought caused an increase in the functional antenna size.The maximum quantum yield of primary photochemistry showed slight differences for all treatments and over time,suggesting that this parameter is less sensitive to drought and O_3 stress.Therefore,the more sensitive components of the photosynthetic electron transport chain appeared to be the probability that an electron from the intersystem electron carriers is transferred to reduce end electron acceptors at the PSI acceptor side(δ_(Ro))and the RC density on a chlorophyll basis(RC/ABS).     

壳聚糖对番茄枯萎病菌的拮抗作用

采用含毒介质法研究了壳聚糖对番茄枯萎病菌菌丝生长和孢子萌发的抑制作用.结果表明,浓度大于1 mg/mL的壳聚糖能明显抑制菌丝生长,各设定浓度均可在一定程度上抑制孢子萌发,而且抑制效果随着处理浓度的增大而增强;浓度大于0.1 mg/mL的壳聚糖处理可诱导初生菌丝发生肿胀、分枝增多且茵体分隔增加及体细胞变短等形态学变化.壳聚糖的抑菌作用机制与其增加茵丝细胞膜的透性有关.     

海岛棉与瑟伯氏棉、辣根棉、裂片棉、松散棉的杂种F_1细胞学研究

本文报道了海岛棉(Gossypium barbadense,(AD)_2)、与瑟伯氏棉(C.thurberi,D_1)、辣根棉(G.armourianum,D_(2-1))、裂片棉(C.lobatum,D_7)和松散棉(C.laxum,D_8)等4个D染色体组的杂种三倍体F_1主要形态遗传变异及其花粉母细胞减数分裂中期Ⅰ染色体配对的研究结果。这4个种间杂种F_1,有的表型象海岛棉,有的象野生二倍体棉,有的表现为中间型。每细胞染色体平均构型依次为:12.83Ⅱ+13.27Ⅰ+0.024Ⅲ;12.10Ⅱ+14.84Ⅰ;12.44Ⅱ+14.24Ⅰ+0.02Ⅲ和12.70Ⅱ+13.40Ⅰ+0.025Ⅲ+0.033Ⅳ;完全配对成13Ⅱ和13Ⅰ的细胞,其比例分别为60.3％、19.9％、42.2％和45.9％。这表明:在这4个D染色体组棉种中,以瑟伯氏棉与海岛棉的关系最为密切,其次为松散棉、裂片棉,而辣根棉的关系最远。本文还讨论了这4个D染色体组种与海岛棉的亲缘关系。     

莫干山的象虫总科昆虫

本文记述浙江林学院等采自莫干山的象虫总科共10种,其中象虫科9种,卷象科1种。     

美国农场的经营管理

重点介绍了美国农场经营管理的基本做法和经验,即以经营中型规模农场为主体;由市场来确定种植计划;主要以一种作物为主要种植对象;农业保险;农业协会;农业社会服务,为农民解决了后顾之忧;重视农科教三结合;坚持用养结合,保护环境.     

美国农业信息工作

介绍了美国农业部有关信息机构的主要工作;美国农业部的经济信息调查内容;美国农业部统计信息调查方法;美国农业信息的分析和发布;有关的信息保密规定;美国农业部农业市场服务局的"市场新闻报告"等六方面的情况.     

竹节参脂溶性成分研究

[目的]分析竹节参脂溶性的化学成分。[方法]用索氏提取法提取竹节参的脂溶性成分,通过气相色谱-质谱（GC-MS）联用技术分离并分析鉴定组分。[结果]共检测出27个峰,鉴定出23种化合物,占总脂溶性成分的93.41%。竹节参地上部分脂溶性成分主要为1-十八碳烯（18.06%）、3-甲基-2-丁酮（12.88%）、3-甲基丁酸（8.40%）、正己酸（6.60%）、辛酸（6.41%）、异丙基乙醚（6.08%）、2-乙氧基戊烷（5.08%）、十二烷（4.93%）、可巴烯（4.17%）。[结论]该试验检测出了竹节参脂溶性化学成分的主要类型及含量,为综合开发利用竹节参提供了科学依据。