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1.
Understanding the effects of elevated O3 (EO3) on belowground process such as soil enzyme activities is essential to evaluate plant physiological reaction and soil processes (e.g. carbon and nitrogen turnover) under predicted increases in atmospheric O3. In this study, O3‐induced changes in soil urease (UA) and catalase activities (CTA) under two contrasting wheat cultivars (O3‐sensitive versus O3‐tolerant) were investigated using a free‐air O3 enrichment (O3FACE) facility in China. EO3 (60 ppb compared with 40 ppb in ambient O3) generally increased UA under the O3‐tolerant cultivar but reduced it under the O3‐sensitive cultivar for different soil depths and growth stages. In contrast, the effects of EO3 on CTA were not consistent and varied with soil depths and growth stages. These results suggest that the O3 sensitivity of wheat cultivars plays an important role in determining the effects of EO3 on soil enzyme activities. The contrasting responses of soil UA and CTA to EO3 may alter the effect of projected increase in tropospheric O3 on soil carbon and nitrogen turnover.  相似文献   

2.
Waterlogging causes long‐lasting damage to wheat (Triticum aestivum). Root growth and respiration were investigated after heading in waterlogged, pot‐grown, wheat plants and also in hydroponically grown, wheat seedlings exposed to a hypoxic treatment. In the pot experiment, plants were subjected to 8 days of waterlogging after heading. This period of waterlogging resulted in reduced shoot and root growth through to maturity. The root CO2 emission rates of previously waterlogged and well‐drained plants were about 220 and 140 nmol g?1 per s, respectively, with the rate differences persisting from 10 days after anthesis through to maturity. In the hydroponic experiments, seedlings (Feekes stage 2.0) were exposed to root‐zone, hypoxic treatment for 10–19 days. The roots showed 27 % higher CO2 emission rates and 37 % higher O2 consumption rates, compared with untreated roots. In whole root systems, the high respiration rates found during hypoxic treatment disappeared during recovery under aerated conditions as a result of the appearance of newly initiated roots. However, measurements of the respiration of the previously hypoxic roots showed abnormally high respiration rates. In roots exposed to hypoxic treatment, total sugar concentrations were 3.6‐times higher than in untreated roots indicating that this elevation of sugar may be responsible for the continued high respiration rate. This study shows that roots exposed to waterlogging or to hypoxic treatments do not increase their weights and thus recover from the metabolic disturbances resulting from these treatments.  相似文献   

3.
为研究不同施氮水平下沿黄常规粳稻根系生理与强、弱势粒灌浆的关系,以2 个沿黄常规粳稻品种‘郑稻19’和‘郑稻20’为材料,大田种植。设置全生育期不施氮肥、全生育期施氮90、180、270、360 kg/hm2 5 种氮肥水平,观察2 个水稻品种根系生理与强、弱势粒灌浆特性。结果表明,随施氮量增加,2 个水稻品种的产量先显著增加后降低,强弱势粒质量、灌浆速率、最大和平均灌浆速率减小或显著减小,到达最大灌浆速率的时间和活跃灌浆期增加或显著增加。与强势粒相比,弱势粒质量较轻,最大和平均灌浆速率较小,到达最大灌浆速率时间较迟,活跃灌浆期较长。2 个水稻品种的根系氧化力、玉米素+玉米素核苷含量和活跃吸收表面积在花后逐渐降低,下降幅度逐渐增大,随施氮量增加先增加后降低。相关分析表明,强、弱势粒灌浆速率在灌浆前期与以上根系生理性状呈显著或极显著负相关,强势粒的最大和平均灌浆速率与根系生理性状呈显著或极显著负相关,而弱势粒则与之呈显著或极显著正相关。  相似文献   

4.
Chemical regulation using plant growth regulators has proved to be potentially beneficial in water‐saving agriculture. This experiment was conducted with winter wheat (Triticum aestivum L. cv. ‘Jingdong 6’) to study the effect of chemical regulation on alleviation of water deficit stress during the grain filling stage. Uniconazole, a plant growth regulator, was foliar sprayed at 85 % (adequate irrigation) and 60 % (deficit irrigation) field capacity. Results showed that the distribution of 3H‐H2O in roots and flag leaf, characteristics of vascular bundle in primary roots and internode below spike, roots activity, transpiration rate and stomatal conductance of flag leaf were negatively affected by deficit irrigation after flowering. Foliar spraying at the early jointing stage with 13.5 gha?1 uniconazole was able to relieve and compensate for the harmful effects of deficit irrigation. Both the area of vascular bundle in primary roots and internode below the ear were increased by uniconazole, while root viability and their ability to absorb and transport water were increased. In the flag leaf, stomatal conductance was reduced to maintain the transpiration rate and water use efficiency (WUE) measured for a single wheat plant was higher. Uniconazole increased WUE by 25.0 % under adequate and 22 % under deficit irrigations. Under adequate irrigations, the 14C‐assimilates export rate from flag leaf in 12 h (E12h) was increased by 65 % and 36 % in early and late filling stages, while under deficit irrigations, the E12h of uniconazole‐treated plants exceeded that of control plants by 5 % and 34 % respectively. Physiological damages caused by water deficiency during the grain filling stage of wheat was alleviated by foliar spraying with uniconazole.  相似文献   

5.
Drought and heat are among the main abiotic stresses causing severe damage to the cereal productivity when occur at reproductive stages. In this study, ten wheat cultivars were screened for combined heat and drought tolerance imposed at booting, heading, anthesis and post‐anthesis stages, and role of the foliage applied plant extracts was evaluated in improving the performance of differentially responding wheat cultivars under terminal heat and drought stresses. During both years, wheat crop was raised under ambient temperature and 70% water holding capacity (WHC) till leaf boot stage. The plant extracts (3% each) of sorghum, brassica, sunflower and moringa were foliage applied at booting, anthesis and post‐anthesis stage; and after one week of application of these plant extracts, combined heat and drought was imposed at each respective stage. Heat and drought stresses were imposed at each respective stage by placing pots in glass canopies with temperature of 4 ± 2°C above than the ambient temperature in combination with drought stress (35% WHC) until maturity. Combination of drought and heat stresses significantly reduced the performance of tested wheat cultivars; however, stress at the booting and heading stages was more damaging than the anthesis and post‐anthesis stages. Cultivars Mairaj‐2008 and Chakwal‐50 remained green with extended duration for grain filling, resulting in the maintenance of number of grains per spike and 100‐grain weight under stress conditions and thus had better grain yield and water‐use efficiency. However, in cultivars Fsd‐2008, and Shafaq‐2006, the combined imposition of drought and heat accelerated the grain filling rate with decrease in grain filling duration, grain weight and grain yield. Foliar application of all the plant extracts improved the wheat performance under terminal heat and drought stress; however, brassica extract was the most effective. This improvement in grain yield, water‐use efficiency and transpiration efficiency due to foliage applied plant extracts, under terminal heat and drought stress, was owing to better stay‐green character and accumulation of more soluble phenolics, which imparted stress tolerance as indicated by relatively stable grain weight and grain number. In crux, growing of stay‐green wheat cultivars with better grain filling and foliage application of plant extracts may help improving the performance of bread wheat under combined heat and drought stresses.  相似文献   

6.
在2004-2005年和2005-2006年小麦生长季,设置不同的灌水时期和灌水量处理,研究了小麦籽粒产量、籽粒淀粉含量、淀粉合成相关酶活性和水分利用效率。结果表明,全生育期不灌水条件下,籽粒中的可溶性淀粉合酶(SSS)和淀粉粒结合态淀粉合酶(GBSS)活性在灌浆初期显著升高,在灌浆中后期显著降低,同时灌浆后期支链淀粉、直链淀粉和总淀粉含量亦显著降低。拔节期和开花期每次灌水60 mm有利于小麦在灌浆中后期保持较高的SSS和GBSS活性,提高灌浆后期籽粒中的支链淀粉、直链淀粉和总淀粉含量;灌水量进一步增加时,灌浆中后期的SSS活性显著降低,GBSS活性升高,灌浆后期的支链淀粉含量降低,直链淀粉含量升高。在两个生长季中拔节期和开花期每次灌水60 mm处理的土壤贮水消耗量较高,水分利用效率最高和籽粒产量较高。在此基础上增加灌水量时,开花至成熟阶段0~60 cm土层的土壤含水量显著升高,土壤贮水消耗量降低,籽粒产量无显著变化,水分利用效率和灌溉水利用效率降低。  相似文献   

7.
灌水量对小麦氮素吸收、分配、利用及产量与品质的影响   总被引：13，自引：0，他引：13  
张永丽  于振文 《作物学报》2008,34(5):870-878
以济麦20和泰山23为试验材料, 在大田条件下研究了灌水量对小麦氮素吸收、分配、利用和籽粒产量与品质及耗水量、水分利用率的影响。2004—2005年生长季, 小麦生育期间降水量为196.10 mm, 两品种的氮素吸收效率、籽粒的氮素积累量和氮肥生产效率均为不灌水处理低于灌水处理, 但籽粒氮素分配比例和氮素利用效率表现为不灌水处理高于灌水处理。拔节期前, 两品种的氮素吸收强度灌水180 mm处理高于灌水240 mm和300 mm两处理, 拔节期后反之; 成熟期, 植株氮素积累量和氮素吸收效率在各灌水处理间无显著差异。济麦20籽粒的氮素积累量和分配比例、氮素利用效率和氮肥生产效率, 均以灌水240 mm处理高于灌水180 mm和300 mm处理; 灌水180 mm和240 mm处理的籽粒产量分别达8 701.23 kg hm-2和9 159.30 kg hm-2, 耗水量为469.29 mm和534.48 mm, 两处理间籽粒品质无显著差异, 且均优于灌水300 mm处理。泰山23籽粒中氮素积累量及分配比例、氮素利用效率、氮肥生产效率和籽粒品质, 在各灌水处理间无显著差异; 灌水180 mm和240 mm处理籽粒产量显著高于其他处理, 分别达9 682.65 kg hm-2和9 698.55 kg hm-2, 其耗水量分别为468.54 mm和532.35 mm。两品种的水分利用率均随灌水量增加而降低。在2006—2007年生长季, 小麦生育期间降水量为171.30 mm, 济麦20和泰山23均以灌水240 mm处理的籽粒产量和水分利用率最高, 其耗水量分别为490.88 mm和474.88 mm。综合考虑产量、品质、氮素利用效率、氮肥生产效率和水分利用率, 生产中济麦20生育期灌水量以180~240 mm为宜; 泰山23在降水量达196 mm条件下, 灌水量以180 mm为宜, 在降水量为170 mm条件下, 灌水量以240 mm为宜。  相似文献   

8.
Pb在小麦植株内吸收、分配和累积的研究   总被引：2，自引：0，他引：2  
通过大田试验，研究了Pb在小麦植株中的吸收、分配和累积的动态变化规律。结果表明，在小麦整个生长过程中，不同部位Pb含量和Pb累积量随着时间的推移而变化，但从总体上看是根〉茎〉子粒。在灌浆末期，各部位Pb含量从大到小依次为：根〉废弃物〉叶〉茎〉叶鞘〉颖片〉穗轴〉子粒，地上各部位Pb累积量从大到小依次为：废弃物〉茎〉叶鞘〉颖片〉叶〉子粒〉穗轴。从结果还可以看出，小麦植株中较易富集Pb的部位是根、废弃物、茎和叶，而子粒中Pb含量和累积量均比较低。小麦在生殖生长阶段的Pb吸收量大于营养生长阶段；拔节一抽穗期和灌浆初期一灌浆中期Pb吸收量及吸收速率显著高于其他时期。  相似文献   

9.
四川盆地小麦籽粒的灌浆特性   总被引：8，自引：0，他引：8  
四川盆地小麦灌浆期长,粒重优势明显,但易受环境影响。2010-2011和2011-2012年连续2个小麦生长季,选用10个品种在3个地点进行灌浆特性研究,以揭示该区域小麦灌浆参数的基因型差异及环境效应。2年平均粒重48.25 g,灌浆分为渐增期(T1)、快增期(T2)和缓增期(T3) 3个阶段,各阶段持续时间为T3 (16.30 d)>T1 (13.41 d)>T2 (12.98 d),其灌浆速率分别为0.618、0.772和2.205 mg grain-1 d-1。3个阶段的干物质积累贡献率依次为21.21% (T1)、58.27% (T2)和20.53% (T3),可见快增期结束时可以积累80%左右的干物质量。基因型、地点和年份对除粒重以外的所有灌浆参数均有显著影响,以年份的效应最大。同一年中,粒重、最大灌浆速率、平均灌浆速率、缓增期灌浆速率、渐增期灌浆速率和快增期灌浆速率主要受基因型的影响,而其他参数则以地点效应大于基因型效应。粒重与平均灌浆速率、最大灌浆速率、快增期灌浆速率和缓增期灌浆速率呈极显著正相关。10个参试品种中,川麦42、川育23和川麦56具开花期早、灌浆速率高、灌浆时间长、粒重大等特征。  相似文献   

10.
以上海种植的小偃54和京411及其杂交后代稳定优选株系6号、7号和10号为材料,通过测定抽穗期剑叶的毫秒延迟发光(ms-DLE)和不同生育期倒数第1片功能叶的光合速率(Pn)、叶绿素含量(Chl)、比叶重(SLW)、Fv/Fm、ATP含量和P700还原初始速率来分析其光合特性的动态变化,为小麦育种选择中改善光合性能提供理论依据和技术途径。结果表明,小麦杂交优选后代6号株系的形态农艺性状近于小偃54,7号株系近于京411,10号株系的变异较大。不同基因型小麦及其杂交优选后代的光合特性与生育时期和衡量指标密切相关,Pn为分蘖期>抽穗期>灌浆期>拔节期,叶绿素含量为灌浆期>抽穗期>分蘖期>拔节期,ATP含量为灌浆期>拔节期>分蘖期>抽穗期,P700还原初始速率为灌浆期>抽穗期>拔节期>分蘖期,各生育期间的Fv/Fm无明显差异。小麦光合特性的超亲优势随生育时期而异,杂交优选后代10号株系的Pn和Chl在灌浆期有超亲优势,ATP含量在抽穗期有超亲优势,SLW和P700还原初始速率介于两亲本间。杂交优选后代株系10号聚合了Pn、Chl和ATP含量的超亲优势,其光合特性优于两亲本,而6号劣于两亲本,7号介于两亲本之间。  相似文献   

11.
以上海种植的小偃54和京411及其杂交后代稳定优选株系6号、7号和10号为材料,通过测定抽穗期剑叶的毫秒延迟发光(ms-DLE)和不同生育期倒数第1片功能叶的光合速率(Pn)、叶绿素含量(Chl)、比叶重(SLW)、Fv/Fm、ATP含量和P700还原初始速率来分析其光合特性的动态变化,为小麦育种选择中改善光合性能提供理论依据和技术途径。结果表明,小麦杂交优选后代6号株系的形态农艺性状近于小偃54,7号株系近于京411,10号株系的变异较大。不同基因型小麦及其杂交优选后代的光合特性与生育时期和衡量指标密切相关,Pn为分蘖期>抽穗期>灌浆期>拔节期,叶绿素含量为灌浆期>抽穗期>分蘖期>拔节期,ATP含量为灌浆期>拔节期>分蘖期>抽穗期,P700还原初始速率为灌浆期>抽穗期>拔节期>分蘖期,各生育期间的Fv/Fm无明显差异。小麦光合特性的超亲优势随生育时期而异,杂交优选后代10号株系的Pn和Chl在灌浆期有超亲优势,ATP含量在抽穗期有超亲优势,SLW和P700还原初始速率介于两亲本间。杂交优选后代株系10号聚合了Pn、Chl和ATP含量的超亲优势,其光合特性优于两亲本,而6号劣于两亲本,7号介于两亲本之间。  相似文献   

12.
花后渍水逆境对冬小麦产量及氮磷钾营养状况的影响   总被引：3，自引：0，他引：3  
采用盆栽模拟渍水逆境试验方法,研究了花后渍水逆境对不同耐渍性小麦品种产量及N、P、K营养状况的影响。结果表明,花后渍水逆境显著降低不同小麦品种粒重和籽粒产量,影响N、P、K吸收、运转和分配,降低根系、茎鞘、功能叶片、籽粒N、P、K积累量,而对N、P、K素在地上部各器官中的分配比例的影响各异,渍水逆境导致根系、功能叶片N、P积累量占单株总积累量的比例下降,茎鞘和籽粒所占比例上升;而对K在地上部各器官中的分配比例影响较小。因此,基肥中施足P、K肥和拔节孕穗期及时追施速效N肥,对于减轻花后小麦渍害,提高受渍小麦粒重和产量具有非常重要的实际意义。  相似文献   

13.
Terminal drought is threatening the wheat productivity worldwide, which is consumed as a staple food by millions across the globe. This study was conducted to examine the influence of foliage‐applied stress signalling molecules hydrogen peroxide (H2O2; 50, 100, 150 μm ) and nitric oxide donor sodium nitroprusside (SNP; 50, 100, 150 μm ) on resistance against terminal drought in two bread wheat cultivars Mairaj‐2008 and BARS‐2009. These stress signalling molecules were applied at anthesis stage (BBCH 61); drought was then imposed by maintaining pots at 35% water holding capacity. Terminal drought caused significant reduction in grain yield of both tested bread wheat cultivars; however, foliage application of both stress signalling molecules at either concentration improved the performance of both bread wheat cultivars. Maximum improvement in 100‐grain weight (12.2%), grains per spike (19.7%), water‐use efficiency (WUE; 19.8%), chlorophyll content index (10.7%), total soluble phenolics (21.6%) and free leaf proline (34.3%), and highest reduction in leaf malondialdehyde contents (20.4%) was recorded when H2O2 was foliage‐applied at 100 μm . Foliage application of SNP enhanced the grains per spike, 100‐grain weight and grain yield by 14.9%, 11.3% and 20.1%, respectively, than control. The foliage‐applied stress signalling molecules improved the accumulation of soluble phenolics, proline and glycine betaine with simultaneous reduction in malondialdehyde contents, which enabled wheat plants to sustain the biological membranes under stress resulting in better stay green (high chlorophyll contents) under drought. This helped improving the grain number, grain weight, grain yield, WUE and transpiration efficiency. In crux, foliage‐applied H2O2 and SNP, at pre‐optimized rate, may be opted to lessen the drought‐induced yield losses in bread wheat in climate change conditions.  相似文献   

14.
Root activity plays a dominant role in grain filling in cereal crops. However, the importance of deep roots for regulating post‐anthesis leaf senescence is not clearly understood in wheat (Triticum aestivum L.). In this study, we used 32P tracing to estimate the difference in wheat root activity at soil depths of 30 and 70 cm and the root restriction method to investigate the effects of vertical distribution of deep roots on leaf senescence, with non‐restricted plants as controls. Recovery of radioactive 32P indicated that deep roots had significantly higher activity than upper roots in wheat. Root restriction at a soil depth of 50 cm caused significant decreases in the activities of superoxide dismutase (EC 1.15.1.1), peroxidase (EC 1.11.1.7), catalase (EC 1.11.1.6) and ascorbate peroxidase (EC 1.11.1.11) at 16 days after anthesis and thereafter resulting in an increase in malondialdehyde. As a result, chlorophyll levels and net photosynthesis decreased. Ultimately, the root‐restricted wheat produced a significantly lower grain yield than the non‐restricted controls. These data suggest that deep roots are pivotal for regulating plant senescence, duration of grain filling, and yield formation.  相似文献   

15.
花后短暂高温对小麦籽粒蛋白质含量的影响及其生理机制   总被引：2，自引：0，他引：2  
采用人工气候室控温, 研究花后短暂高温对弱筋小麦扬麦9号和中筋小麦扬麦12籽粒蛋白质含量的影响及其生理机制。结果表明,开花至花后33 d,35℃以上高温处理使籽粒蛋白质含量显著高于对照, 温度越高上升越显著;花后33 d以后遇高温胁迫对蛋白质含量影响相对较轻。籽粒灌浆前期,花后6~8 d 35℃以上高温胁迫对蛋白质含量的影响最大,花后1~3 d处理影响次之;在灌浆中后期,花后19~21 d高温胁迫对蛋白质含量影响较大,花后36~38 d处理的影响较小,且灌浆前期籽粒蛋白质含量受高温胁迫的影响较灌浆中后期大。剑叶硝酸还原酶（NR）和谷氨酰胺合成酶（GS）活性以25℃处理较高,随温度的升高而降低, 与籽粒蛋白质含量呈极显著负相关。高温胁迫导致粒重下降,籽粒蛋白质含量相对上升。花后短暂高温胁迫导致弱、中筋小麦籽粒蛋白质品质变劣。  相似文献   

16.
不同施氮时期对冬小麦根系衰老的影响   总被引：39，自引：3，他引：39  
姜东  于振文 《作物学报》1997,23(2):181-190
采用温室盆栽和田间土柱栽培的方法研究了不同施氮时期对冬小麦根系衰老的影响。结果表明,冬小麦根系从开花后14天开始加速衰老,与籽粒灌浆速率高峰期相对应。20～40cm和40～100cm土层根衰老迟于0～20cm土层根。根系衰老与旗叶衰老、及与籽粒灌浆速率密切相关。20～40cm和40～100cm土层中的根对旗叶衰老有较大影响;在籽粒形成期,0～20cm土层根对粒重形成的作用大,到灌浆期,20～40cm和40～60cm土层根对粒重形成起重要作用。鲁215953和鲁麦14品种分别于拔节期和挑旗期追施氮肥,可延缓小麦根系的衰老,提高籽粒灌浆速率,增加粒重和产量。  相似文献   

17.
Moderate to severe drought (water stress) at the reproductive stage is common in the U.S. Southern High Plains (SHP), where wheat is grown as a major winter crop. The objective of this study was to better understand the physiological basis of drought tolerance in elite wheat cultivars. A 2‐yr glasshouse study was conducted using three cultivars (TAM 111, TAM 112 and TAM 304) and two water treatments (wet: adequate water and dry: water‐limited). Overall, TAM 111 and TAM 112 used more water for cumulative evapotranspiration (ET) and had more tillers and greater root mass and shoot mass compared to TAM 304. In the dry treatment, TAM 112 had 67% and 81% more grain yield than TAM 111 and TAM 304, respectively. Water use efficiency for grain (WUEg) and water use efficiency for biomass (WUEbm) were also greater in TAM 112 compared to the other cultivars in the dry treatment. The flag leaves in TAM 112 at mid‐grain filling stage (about 15 days after flowering) had lower stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr) and net photosynthetic rate (Pn), but higher photosynthetic water use efficiency (PWUE) than TAM 111 and TAM 304 under water stress. This study demonstrated a distinct role of gas exchange parameters in response to drought, and TAM 112 was more efficient than TAM 111 and TAM 304 in evolving physiological mechanisms to adapt to water stress.  相似文献   

18.
冬小麦抗旱生理特性的研究   总被引：42，自引：3，他引：42  
李德全  郭清福 《作物学报》1993,19(2):125-132
试验结果表明，干旱胁迫下抗旱性不同的冬小麦品种的抗旱系数为：昌乐5号＞秦麦3号＞山农587＞济南13＞鲁麦5号＞烟农15。五个生育期的叶片渗透调节能力为抗旱性强的品种大于抗旱性弱的品种，抗旱系数和渗透调节能力是反映冬小麦抗旱特性的两个最好指标。拔节、孕穗和开花期抗旱性强的品种气孔阻力比抗旱性弱的品种大，灌浆和  相似文献   

19.
Post‐head‐emergence frost (PHEF) has a detrimental impact on grain yield of wheat, and an enhanced photosynthate supply could alleviate the negative impact. However, modulation of photosynthate availability at different growth stages may exert different effects on the plant physiology and grain yield. The objective of this study was to investigate the roles of the enhanced photosynthate supply by growing the plants at elevated [CO2] (800 ppm) during different growth stages on yield performance of wheat exposed to PHEF. The results showed that the PHEF caused a high grain yield loss in wheat, and an increase in photosynthate supply during the reproductive growth stage mitigated the negative impact, whereas that at vegetative growth stage exacerbated the negative impact of PHEF. The opposite effects exerted by the enhanced photosynthate supply at vegetative stage versus at reproductive stage on yield performance could be associated with its distinguished roles in influencing plant physiology at the two growth stages. The positive effect of the increased photosynthate supply at reproductive stage was due to an improved grain filling and regeneration of effective tillers upon recovery from frost, whereas the negative effects of the enhanced photosynthate supply at vegetative growth stage were primarily due to an accelerated early vegetative growth that increased the sensibility of the plants to PHEF.  相似文献   

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