大田增温对夏玉米产量和品质的影响

研究了大田条件下增温（3 ℃）对夏玉米产量和品质的影响. 结果表明：增温条件下玉米的籽粒产量显著降低,农大108（ND108）和掖单13号（YD13）分别减产46.6%和45.1%.增温也显著影响了玉米的籽粒品质,与对照相比,ND108和YD13的粗蛋白含量分别提高了11.6%和2.02%;粗脂肪含量分别降低了38.9%和9.6%;淀粉含量分别降低了7.0%和8.4%,且主要降低了支链淀粉的含量;赖氨酸含量则分别降低了58.9%和51.2%.     

遮荫对夏玉米产量及生长发育的影响

在大田条件下研究了不同时期和不同程度遮荫对夏玉米产量及生长发育的影响.结果表明,遮荫显著降低玉米产量.不同时期遮荫对其影响不同,花粒期（从开花到成熟期）遮荫的影响最显著,农大108（ND108）和掖单13号（YD13）遮荫50%、90%处理分别减产67.5%、79.4%和82.9%和86.7%,其次是穗期（从拔节到开花期）遮荫,ND108和YD13分别减产34.1%、55.3%和47.2%、65.7%,而苗期（从出苗到拔节期）遮荫对其影响相对较小,ND108和YD13分别减产16.9%、24.5%和18.9%、24.3%.遮荫对YD13产量的影响大于ND108.遮荫时期对玉米产量的影响显著地大于遮荫程度.遮荫后两个玉米品种的生育进程都延迟,并随着遮荫程度的增加,对其影响加剧.穗期遮荫显著影响玉米的穗分化,花丝数和雄穗分枝数显著降低,对YD13的影响大于ND108.苗期和穗期遮荫显著抑制玉米叶面积、株高和茎节的生长.     

遮荫条件下草莓的光合特性变化

对宝交早生和硕丰两个草莓品种遮荫处理后测定其光合特性变化结果表明,遮荫处理使两个草莓品种叶片光合速率显著降低,分别下降了20%和47%,而表观量子效率分别提高了13%和8%.叶片中叶绿素含量升高而可溶性蛋白含量显著降低.光系统Ⅱ电子传递活性(PSⅡ活性)分别下降了22.5%和53.7%.1,5二磷酸核酮糖羧化酶(Rubisco)活性分别降低了19.6%和35.3%.进一步讨论了草莓光饱和速率下降的生理基础.     

烟草叶片发育过程中光合功能衰退与H_2O_2积累的关系

以烟草(NicotianatabacumL.cvNC89)为材料,研究了叶片发育过程中H2O2积累与叶绿体光合功能衰退、抗坏血酸-谷胱甘肽(AsA-GSH)循环的关联。结果表明,光合功能衰退过程中,各光合参数均表现为先缓慢后快速的下降趋势,核酮糖-1,5-二磷酸羧化酶(RuBPCase)活性下降较电子传递活性下降迅速,H2O2含量与叶绿素含量、光合速率、RuBPCase活性、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)活性显著负相关。H2O2的定位染色也证实光合功能衰退与H2O2积累密切相关。APX和GR在光合功能可逆衰退阶段维持较高水平,不可逆衰退阶段下降稍快。烟草叶片光合功能衰退快于AsA-GSH循环运转的下调。     

不同增温处理对夏蜡梅光合特性和叶绿素荧光参数的影响

利用红外线辐射器(Electric radiant infrared heater)设置3个不同增温处理:(1)晚上增温2℃(18:00—翌日6:00);(2)白天增温2℃(6:00—18:00);(3)全天增温2℃;以不做增温处理作为对照,模拟气候变暖对夏蜡梅(Sinocalycanthus chinensis)的光合特性和叶绿素荧光参数的影响。3个季节中,3种增温处理下的夏蜡梅净光合速率(Anet)和最大净光合速率(Amax)均高于对照。表明3种增温处理均可以提高夏蜡梅的光合作用能力。增温处理提高了气孔导度(Gs)、暗呼吸速率(Rd),降低了胞间CO2浓度(Ci)。3种增温处理中,夏蜡梅在3个生长季节的Anet和Amax均以白天增温最大,表明白天增温下夏蜡梅具有最高的光合作用能力。白天增温处理下的表观量子效率(AQY)、光饱和点(LSP)显著高于全天增温、晚上增温以及对照。白天增温和晚上增温使夏蜡梅的相对叶绿素含量显著增加,且白天增温叶绿素相对含量显著高于晚上增温、全天增温及对照。白天增温、晚上增温与全天增温处理下的夏蜡梅的PSⅡ最大光化学效率(Fv/Fm)均显著低于对照,在12:00和14:00时,三者之间存在显著性差异,以白天增温最高,晚上增温次之,全天增温最低。总之,3种增温处理夏蜡梅的光合能力总体上均有不同程度的增强,且在白天增温处理下,夏蜡梅的Anet、Amax值最高,表明白天增温下夏蜡梅具有最高的光合能力,这与白天增温引起的相对叶绿素含量增高、叶片对强光的适应能力加强、较低程度的光胁迫等因素有关。本研究说明未来增温条件下,将提高夏蜡梅的光合生理活性,促进夏蜡梅的生长。     

油菜终花后角果和叶片光合对籽粒产量和品质的影响

以‘秦优7号’油菜品种为材料,设置叶片和角果遮光及摘除叶片处理,通过田间试验测定分析终花后角果和叶片的光合特性及其对籽粒产量、含油量及脂肪酸组成的影响。结果显示:(1)终花后油菜角果遮光使籽粒的千粒重、产量、含油量分别显著降低54.7%、62.1%、44.2%,且籽粒中硫甙含量及脂肪酸中棕榈酸、硬脂酸含量显著升高,亚麻酸含量显著降低。(2)叶片遮光和摘除叶片分别显著降低角粒数11.7%、11.3%,降低籽粒千粒重22.5%、17.9%,单株产量分别降低35.3%、44.7%,使籽粒脂肪酸中亚油酸、亚麻酸等含量显著增加,但对籽粒含油量无显著影响。(3)终花后油菜绿色角果皮最大面积是绿叶面积的1.54倍,角果叶绿素a、b以及类胡萝卜素含量显著低于叶片,但角果的净光合速率、蒸腾速率显著高于叶片;且角果层的光辐射强度显著高于角果层下的叶片层;角果响应光辐射强度的光补偿点、光饱和点均显著高于叶片;即角果能够适应较高强度光辐射环境。研究发现,油菜结角期角果层接受大部分光辐射,角果的光合活性显著高于叶片,是主要的光合器官,角果光合状况对籽粒产量、含油量及脂肪酸组成有显著影响。     

垄作栽培对高产田夏玉米光合特性及产量的影响

试验于2006-2007年在河南省浚县农业科学研究所试验田进行,以传统平作为对照,研究了垄作栽培对夏玉米光合特性和产量的影响.结果表明,垄作提高了夏玉米光合速率Pn、叶片蒸腾速率Tr和气孔导度Gs,且其日变化均呈单峰曲线,12:00达到最大值,而细胞间隙二氧化碳浓度Gi有所降低,其日变化与Pn相反,呈倒抛物线型.垄作栽培夏玉米的最大光化学效率Fv/Fm和实际光化学效率φPSⅡ均有所增加.与平作相比,垄作后期叶面积衰减较慢,籽粒蜡熟期和成熟期垄作比平作叶面积指数分别高6.4％和3.7％,减少了漏光损失,垄作栽培延长了叶片功能期,促进光合产物的积累及向籽粒的转移,有利于后期玉米籽粒充实,千粒重显著高于平作,产量提高9.6％.     

密度和种植方式对夏玉米酶活性和产量的影响

在豫北灌区的生产条件下,以郑单958和浚单20为试验材料,研究了不同密度和种植方式对夏玉米碳氮关键酶的影响。结果表明:生育后期夏玉米叶片硝酸还原酶(NR)、谷氨酰胺合成酶(GS)和籽粒蔗糖磷酸合成酶(SPS)、蔗糖合成酶(SS)活性均呈先升高后降低的变化趋势,叶片NR和GS活性峰值出现在吐丝期,籽粒SPS和SS活性峰值出现在灌浆后15d。基因型、密度和种植方式对夏玉米生育后期叶片NR、GS和籽粒SPS、SS活性均有显著影响,而3因素间总体上没有显著的互作效应。郑单958生育后期叶片NR、GS和籽粒SPS、SS活性均显著高于浚单20,分别提高5.02%、7.40%、6.25%和4.43%。在6.75—9.00万株hm2的范围内,随着密度的增大,夏玉米生育后期叶片NR、GS和籽粒SPS、SS活性显著降低。与60cm等行距种植方式相比,80cm-40cm宽窄行种植方式下夏玉米生育后期叶片NR、GS和籽粒SPS、SS活性均显著提高,分别提高6.23%、9.25%、6.87%和2.84%。在采用宽窄行种植、密度为8.25万株hm2时,产量最高。     

植酶Q9对大田遮阴夏玉米产量和衰老特性的调控作用

黄淮海夏季太阳辐射量降低以及种植密度增加引起了夏玉米冠层光照不足,产量大幅降低。本试验选用夏玉米品种‘登海605'(DH605)为试验材料,设置3个遮阴处理:花粒期遮阴(S₁)、穗期遮阴(S₂)和全生育期遮阴(S₃),以大田自然光照为对照(CK),并选用化控试剂植酶Q9(原液稀释100倍)对遮阴处理和CK进行外源调控,即花粒期遮阴-植酶Q9(S₁Q)、穗期遮阴-植酶Q9(S₂Q)、全生育期遮阴-植酶Q9(S₃Q)及大田自然光照-植酶Q9(CKQ),化控处理以同时期喷施清水为对照,探讨植酶Q9对大田遮阴夏玉米衰老特性的调控作用。结果表明: 遮阴显著降低了夏玉米的叶面积指数(LAI)、功能叶片叶绿素相对含量值(SPAD值)和净光合速率,进而显著降低了夏玉米产量。同时,遮阴夏玉米穗位叶的超氧物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性显著降低,丙二醛(MDA)、游离脯氨酸含量显著增加,可溶性蛋白含量显著降低。喷施植酶Q9后,S₃Q和S₂Q的LAI、功能叶片SPAD值和净光合速率显著提高;S₃Q、S₂Q、S₁Q的MDA和游离脯氨酸含量显著降低,可溶性蛋白含量和POD活性显著提高,S₂Q、S₃Q各时期的SOD和CAT活性显著提高;S₃Q、S₂Q、S₁Q的产量分别较S₃、S₂、S₁平均提高19%、8%、7%,CKQ与CK间无显著差异。因此,喷施植酶Q9通过提高弱光胁迫下夏玉米的光合能力,延缓叶片的衰老,增加产量,可有效缓解弱光胁迫导致的减产危害。     

两株链霉菌对玉米的促生增产作用及机理

为探索娄彻氏链霉菌(D74)和密旋链霉菌(Act12)及其混合菌剂对玉米生长的影响,采用皿内发芽试验、沙培试验及小区试验观察供试链霉菌无细胞发酵滤液及活菌制剂种子包衣对玉米生物学性状、叶片诱导酶活性、光合作用、穗性状、产量及品质的影响.结果表明: 供试链霉菌无细胞发酵滤液处理玉米种子可促进玉米胚根、胚轴及幼苗生长,提高玉米幼苗叶片诱导酶活性.D74发酵液稀释1000倍处理可使玉米胚根长度、胚轴长度及须根数较对照分别增加43.4%、26.4%和100.7%(P＜0.05);D74原液可使玉米叶片多酚氧化酶(PPO)活性较对照增加40.2%.Act12发酵液稀释100倍处理可使玉米胚根长度、胚轴长度和须根数较对照分别增加36.3%、36.3%和117.5%(P＜0.05),玉米幼苗总鲜质量、根系鲜质量分别较对照增加31.1%、36.6%(P＜0.05);Act12稀释10及1000倍处理玉米种子可使玉米叶片PPO活性分别较对照增加38.1%和39.5%(P＜0.05).混合菌剂种子包衣具有以下作用:1)促进玉米根系发育;2)显著增强叶片光合能力;3)显著改善穗性状并提高籽粒产量;4)显著促进籽粒灌浆速度;5)明显提高灌浆期玉米叶片诱导酶活性.表明供试链霉菌制剂包衣玉米种子可显著影响玉米的生物学特性、光合生理及生化代谢,刺激根系发育,促进玉米生长,提高产量.     

冬麦春播条件下旗叶光合特性、叶绿素荧光参数变化及其与产量的关系

以长江中下游、西南麦区的5个优良冬播小麦品种为材料,在忻定盆地春播(早播、适播)条件下,于2013-2014年对开花期、灌浆期的旗叶光合指标、叶绿素含量及叶绿素荧光参数进行测定,并分析这些参数与产量的相关性.结果表明： 品种间大多荧光参数(除叶绿素外)差异显著,且相关性显著;叶绿素变异系数较小(0.12～0.17),吸收光能为基础的性能指数(PI_abs)变异系数较大(0.32～0.39),两参数与产量偏相关系数为0.70～0.81;早播条件下,籽粒产量与PI_abs(灌浆期、开花期)、灌浆期叶绿素呈显著正效应,与灌浆期旗叶在I点的相对可变荧光强度(V_i)呈显著负效应,且产量的81.1%～82.8% (2013、2014年)可由这3因素的变异决定;不同品种表现出不同的播期效应,且两年变化趋势基本一致：扬麦13(春性、中早熟)旗叶光合速率、叶绿素及绝大多数荧光参数和产量均显著高于其他品种,且适宜早播.早播条件下灌浆期旗叶叶绿素含量、PI_abs、光合速率可作为选择高光效小麦资源的重要评价指标.     

不同年代冬小麦品种旗叶光合特性和产量的演变特征

选用20世纪50年代的望水白（WSB）和碧玛1号(BM1)、70年代的郑引1号(ZY1)和扬麦1号(Y1)及90年代的豫麦34(Y34)和宁麦9号(N9)冬小麦品种为材料,采用大田试验研究了小麦旗叶光合特性和籽粒产量的演变特征.结果表明：与其他年代品种相比,90年代品种灌浆期旗叶具有较高的叶绿素含量、净光合速率（P_n）、PSⅡ最大光化学效率(F_v/F_m) 和实际光量子效率（Φ_PSⅡ）,以及较高的光化学淬灭(q_P)和非光化学淬灭(q_N),并且其光合叶面积功能期长,衰老较慢.90年代品种收获指数高于50和70年代品种,平均群体产量分别比50和70年代品种提高了25.90%和11.29%.因此,在小麦品种改良过程中,花后光合能力的提高及光合持续期的延长是小麦产量增长的重要生理基础.     

Photosynthetic Characteristics of Non-Leaf Organs of Winter Wheat Cultivars Differing in Ear Type and their Relationship with Grain Mass Per Ear

Chlorophyll content, photosystem 2 functioning (F_v/F_m, F_v/F₀), activity of ribulose-1,5-bisphosphate carboxylase/oxygenase, and net photosynthetic rates (P _N) of flag leaf blade, sheath, peduncle, and ear organs were assessed in large-ear type (Pin 7) and small-ear type (ND93) wheat cultivars. Some differences were found in photosynthetic properties between different green plant parts, the values of all studied parameters in ear parts being higher in Pin7 than in ND93. Furthermore, ear surface areas and ear P _N in 26 wheat genotypes measured at anthesis showed highly significant positive correlation with grain mass per ear. Hence a greater capability of ear photosynthesis may result in a greater grain yield in large-ear type cultivars.     

胺鲜酯对高产夏玉米产量及叶片光合羧化酶和保护酶活性的影响

采用田间小区试验,以高产玉米新品种登海661为材料,研究了拔节期叶面喷施10、20和40 mg·L^-1的胺鲜酯（DA-6）对玉米叶片光合羧化酶、保护酶活性和产量的影响.结果表明：喷施胺鲜酯各处理玉米分别比对照（含有表面活性剂和水）增产10.0%(10 mg·L^-1)、8.9%(20 mg·L^-1)和9.4%(40 mg·L^-1),增产效果显著,但各浓度间差异不显著.胺鲜酯处理后,花后玉米的叶面积指数、光合速率、RuBP羧化酶和PEP羧化酶活性均显著上升(P＜0.05),且对光合速率、RuBP羧化酶和PEP羧化酶活性的影响随着处理浓度的增加而提高;与对照相比,胺鲜酯处理后吐丝期、灌浆期、乳熟期和蜡熟期叶片SOD、CAT、POD和GSTs活性及可溶性蛋白质含量显著提高(P＜0.05),MDA含量显著降低(P＜0.05),其中CAT活性随着处理浓度的增加呈上升趋势,其余生理指标各浓度间无显著性差异.     

Photosynthetic characteristics and enzymatic antioxidant capacity of flag leaf and the grain yield in two cultivars of Triticum aestivum (L.) exposed to warmer growth conditions

Using late sowing practice, the reproductive growth (anthesis and kernel filling) phase of two wheat cultivars, HD 1553 and HD 2307 was exposed to warmer growth conditions, and the effect on grain yield was examined. The grain weight declined in late-sown plants of both cultivars, but the number of grains per spike decreased drastically in HD 1553 plants. In this cultivar exposure to warmer temperature during reproductive phase led to 67% fewer grains per spike. Examination of photosynthetic and enzymatic antioxidant capacity in flag leaves of late-sown plants revealed a marked reduction in chlorophyll and carotenoid pigmentation in addition to a decline in the activity of H2O2 metabolising enzymes in HD 1553 cultivar. The photo-oxidative pigment loss due to warmer growth conditions in late-shown HD 1553 plants could lead to a reduction in flag leaf photosynthesis and contribute to poor grain yield.     

RuBP carboxylase activity in wheat following ear emergence and evaluation of the role of ear

Ribulose bisphosphate carboxylase activity and chlorophyll content were measured in the leaves and reproductive parts of two wheat cultivars after ear emergence. The chlorophyll content of the flag leaf was mostly higher than that of the awns and glumes. Awns had the highest chlorophyll content among reproductive parts. Light transmission to the lower leaves was higher in the dwarf cultivar Moti than in the medium tall cultivar Kalyansona. RuBP carboxylase activity in Kalyansona leaves was higher than in Moti leaves. In postanthesis stages there was no difference in RuBP carboxylase activity in the flag leaf and lower leaves between cultivars. Awns had the maximum activity of RuBP carboxylase followed by glumes and grains among ear parts. The relative capacity for photosynthesis in the ear parts was several times higher than in the flag leaf on a unit chlorophyll basis. It is suggested that in a crop canopy in the field, the spike(ear) may have a greater importance in grain development than has been previously estimated.     

Effects of nitrogen deficiency on photosynthetic traits of maize hybrids released in different years

BACKGROUND AND AIMS: New maize (Zea mays) hybrids outperformed old ones even at reduced N rates. Understanding the mechanisms of the differences in performance between newer and older hybrids under N deficiency could provide avenues for breeding maize cultivars with large yield under N deficiency, and reduce environmental pollution caused by N fertilizers. METHODS: N deficiency effects on grain weight, plant weight, harvest index, leaf area and photosynthetic traits were studied in the field for six maize hybrids released during the past 50 years to compare their tolerance and to explore their physiological mechanisms. KEY RESULTS: N deficiency decreased grain yield and plant weight in all hybrids, especially in the older hybrids. However, there was no significant difference in harvest index, rate of light-saturated photosynthesis (Psat) 20 d before flowering, leaf area or plant weight at flowering between the N-deficient and control plants of all hybrids. Dry matter production after flowering of the N-deficient plants was significantly lower than that of the control plants in all hybrids, especially in the older hybrids, and was mostly due to differences in the rate of decrease in photosynthetic capacity during this stage. The lower Psat of the older hybrids was not due to stomatal limitation, as there was no significant difference in stomatal conductance (gs) and intercellular CO2 concentration (Ci) between the hybrids. N deficiency accelerated senescence, i.e. decreased chlorophyll and soluble protein contents, after anthesis more for the earlier released hybrids than for the later ones. N deficiency decreased phosphoenolpyruvate carboxylase (PEPCase) activity significantly more in older hybrids than newer hybrids, and affected the maximal efficiency of PSII photochemistry (Fv/Fm) only in the old hybrids and at the late stage. CONCLUSIONS: Compared with older (earlier released) hybrids, newer (later released) hybrids maintained greater plant and grain weight under N deficiency because their photosynthetic capacity decreased more slowly after anthesis, associated with smaller non-stomatal limitations due to maintenance of PEPCase activity, and chlorophyll and soluble protein content.     

Physiological N response of field-grown maize hybrids (Zea mays L.) with divergent yield potential and grain protein concentration

Fertilizer N availability impacts photosynthesis and crop performance, although cause–effect relationships are not well established, especially for field-grown plants. Our objective was to determine the relationship between N supply and photosynthetic capacity estimated by leaf area index (LAI) and single leaf photosynthesis using genetically diverse field-grown maize (Zea mays L.) hybrids. We compared a high yield potential commercial hybrid (FR1064 x LH185) and an experimental hybrid (FR1064 x IHP) with low yield potential but exceptionally high grain protein concentration. Plant biomass and physiological traits were measured at tassel emergence (VT) and at the grain milk stage (R3) to assess the effects of N supply on photosynthetic source capacity and N uptake, and grain yield and grain N were measured at maturity. Grain yield of FR1064 x LH185 was much greater than FR1064 x IHP even though plant biomass and LAI were larger for FR1064 x IHP, and single leaf photosynthesis was similar for both hybrids. Although photosynthetic capacity was not related to hybrid differences in productivity, increasing N supply led to proportional increases in grain yield, plant biomass, LAI, photosynthesis, and Rubisco and PEP carboxylase activities for both hybrids. Thus, a positive relationship between photosynthetic capacity and yield was revealed by hybrid response to N supply, and the relationship was similar for hybrids with a marked difference in yield potential. For both hybrids the N response of single leaf CER and initial Rubisco activity was negative when expressed per unit of leaf N. In contrast, PEP carboxylase activity per unit leaf N increased in response to N availability, indicating that PEP carboxylase served as a reservoir for excess N accumulation in field-grown maize leaves. The correlation between CER and initial Rubisco activity was highly significant when expressed on a leaf area or a total leaf basis. The results suggest that regardless of genotypic yield potential, maize CER, and potentially grain yield, could be improved by increasing the partitioning of N into Rubisco.