利用14C研究不同氮素水平下玉米光合产物的运输与分配

本研究表明,玉米光合产物的运输中心,因生育时期不同而异,其输送中心和生育中心是一致的,施肥量间强度有别,但趋势一致。拔节期以未展全叶和幼茎为中心;大喇叭口期以未展全叶、茎秆伸长节和雄穗为主;抽丝期以生殖器官为主;乳熟期和蜡熟期以籽粒为主。不同叶位组内分配的光合产物趋势是上位叶组>中位叶组>下位叶组。氮素化肥用量对光合产物的运输和分配量有随施肥量的增加而增加的趋势。     

小麦产量形成的生理基础(续完)

三、光合产物的运输和分配众所周知,结实器官的形成及籽粒的充实,都要依靠其他绿叶部分提供光合产物,这就涉及同化产物的运输和分配问题。小麦的同化产物系以蔗糖形式通过筛管运输的,运输速度通常为10—100厘米/小时。但     

高粱单叶对籽粒产量贡献率的研究

采用去叶法用贡献率指标确定出高粱最大功能叶为上数第５叶,这个最大功能叶具有明显的位置效应。各叶位在对籽粒产量共同起作用地,每一叶位都存在不同程度的补偿效应,这种补偿效应的大小因叶片功能强弱而异,叶片功能强所得到的补偿效应低。抽穗前贮存在茎鞘中的光合产物的输出率也因叶片功能强弱而异,叶片功能强,输出则少。     

不同肥力对晚播小麦开花后地上器官干物质积累运转及产量的影响

对不同肥力水平下晚播小麦开花后地上器官光合产物积累、运转和对产量影响的研究表明,开花后同一天,各地上器官光合产物的积累量均随肥力水平的提高而增加。施肥使叶鞘、茎秆光合产物积累量于开花后１０ｄ达到最大;地上器官光合产物对籽粒的贡献率随着施肥水平的提高而呈增加趋势,施肥处理的贡献率为茎秆＞叶片＞穗部器官＞叶鞘,不施肥处理为茎秆＞叶片＞叶鞘＞穗部器官。     

剪叶对豫农202籽粒灌浆与干物质积累的影响

为了探讨小麦新品种豫农202植株上部三片叶对籽粒干物质积累的影响,分别在小麦开花期和灌浆中期进行了不同的剪叶处理,分析了不同剪叶处理对剩余叶片的SPAD值、籽粒灌浆速率及籽粒干物质积累量的影响。结果表明,小麦开花期和灌浆中期剪叶后,植株上部三片叶的SPAD值在不同处理间具有明显差异,剪去部分叶片后剩余叶片的SPAD值均有所提高。从剪叶对籽粒灌浆速率和干物质积累量的影响来看,开花期剪叶的影响程度显著大于灌浆中期剪叶。不同剪叶处理间籽粒的灌浆速率和干物质积累量存在明显差异,开花期剪去倒一叶对灌浆速率具有较大的负向效应,其干物质积累量比对照降低了21.22%;剪去倒三叶对灌浆速率具有较大的正向效应,其干物质积累量增加了12.20%。灌浆中期剪叶后,所有剪叶处理的籽粒灌浆速率和干物质积累量均低于对照,且剪去的叶片越多灌浆速率和干物质积累量下降的幅度越大,同时剪去倒一叶和倒二后下降的幅度最大。     

向日葵叶片动态及功能叶的研究

本文研究了向日葵叶生长动态及功能叶。最初8叶对生,其余轮生。现蕾前叶从茎底部向顶端依次已全部长出,现蕾后到开花阶段则全部展开、扩大,开花期最大叶面积可达1.4m以上。植株呈两头小中间大株型。开花前底部叶片开始黄落,灌浆阶段仅余69％的叶片。生长过程上部邻近的展开叶给新生叶及花盘提供光合产物。主要功能叶层,在花序及开花阶段为植株中部偏上的第19—30叶、灌浆阶段为靠近花盘的第31—39叶,这些叶片的光合强度较大,平均3g/m~2/小时,距花盘越远的叶片功能越小。     

小麦根系扩展深度对旗叶衰老及光合产物分配的影响

作物根系生长与地上部的生长发育密切相关。为了研究高产小麦根系的分布与旗叶衰老及光合产物运转分配的关系通过池栽的方法，在物理性人为控制根系扩展深度的条件下，对小麦旗叶生理状况及光合产物的分配进行了调查。结果表明，随着小麦群体根系在土壤中扩展深度的增加，小麦生育后期旗叶的衰老速度减缓（SOD、POD活性增加，MDA含量降低），旗叶叶绿素降解速度变慢，而光合作用强度增加。不仅如此，根系的扩展深度还对光合产物的运转分配有影响。根系分布较浅时，运输分配到茎鞘等营养器官的干物质比例较大，而根系扩展较深时，则运输分配到穗部等生殖器官的干物质比例较大。     

乙烯利对花生氮代谢和光合特性的影响

采用田间小区试验探讨了不同乙烯利浓度对花生氮代谢和光合特性的调控效果.试验结果表明,不同浓度的乙烯利能够明显提高花生功能叶叶绿素含量和光合速率,有利于功能叶光合产物的合成和累积以及籽粒产量和品质的提高;有利于花生功能叶中的氮素向籽粒等库的转运,不同浓度的各处理功能叶中全氮、蛋白氮含量的减少量均高于对照;且能够明显提高花生结荚前期功能叶硝酸还原酶、谷氨酰胺合成酶和转化酶活性及结荚中、后期功能叶中蛋白水解酶活性;能明显提高花生籽粒全氮、蛋白氮的含量,且以150 mg/L浓度最合理.     

小麦开花后不同光合器官对籽粒品质的影响

为探讨不同光合器官对小麦籽粒品质的作用,以永良4号为供试品种,在开花后通过剪叶遮光(包括剪旗叶、剪旗叶+倒二叶、包旗叶鞘、包穗、包穗+穗下节间)等处理,研究了叶器官和非叶器官对小麦籽粒营养物质含量及单穗生产量的影响.结果表明,剪叶遮光后小麦籽粒中淀粉、脂肪、铁含量比正常生长降低,灰分、磷、钾、锌、钙含量提高,而对蛋白质含量影响很小;剪叶遮光后小麦籽粒淀粉、脂肪、蛋白质、灰分、磷、钾、锌、铁、钙筚穗产量均比正常生长降低.非叶器官对籽粒营齐物质含量以及生产量的影响均大于叶器官.     

不同硒源对芝麻富硒效应的影响

芝麻品种豫芝10号施用不同含硒量的硒矿粉、富硒复混肥(含硒复混肥)、亚硒酸钠(Na2SeO3)溶液试验结果表明:①不同形态的硒源均能提高芝麻的含硒量,施入3种不同形态硒源的芝麻植株含硒量为0.216mg/kg～0.614mg/kg,比对照的0.108mg/kg高120.65%～456.11%,平均提高了277.5%;②芝麻不同部位的富硒效果不同,籽粒＞荚＞叶＞根,生殖器官优于营养器官;③营养器官中较成熟的叶片含硒量大于较幼嫩的叶片,说明芝麻的富硒存在着一个积累的过程;④在当季的芝麻栽培中,施用Na2SeO3的芝麻籽粒中含硒量平均为1.1185mg/kg,富硒复混肥处理平均为0.6545mg/kg,富硒矿粉处理为0.4390mg/kg,比对照(0.1640mg/kg)增加167.7%～ 582.0%,平均增加345.9%.3种硒源的当季效果依次为Na2SeO3＞富硒复混肥＞富硒矿粉;⑤用Na2SeO3溶液根外追施,其适宜、经济有效的浓度为50mg/kg～100mg/kg,超过350mg/kg时,芝麻叶片灼伤严重,籽粒含硒量降低.     

芝麻不同时期去叶对蒴果发育和产量的影响及保叶增产措施

采用定株观察，以芝麻生长正常单株为对照，研究不同生育时期，不同蒴果发育时期去叶，对芝麻农艺性状和单株产量的影响。结果表明，随着芝麻生育进程，终花期，封顶期，盛花期去叶减产值幅度递增。相同植株同天开花采取不同时期去叶所结蒴果分别与对照相比，去叶时间越早秕籽率越高，千粒重越低。同时还进一步研究出延长芝麻中上部叶片功能期，提高单株产量的技术措施。     

灌浆后期去叶对夏玉米生长发育及子粒含水率的影响

以郑单1002为材料,设置灌浆中后期(灌浆36 d)不同穗部及穗下不同数量的去叶处理,研究去叶后对玉米群体光合性能、冠层结构、产量以及子粒含水率等的影响。结果表明,穗部叶及穗部以下叶保留3~4片叶,产量不降低;去叶较多情况下表现为减产;不保留穗位叶较对照减产了12.36%,子粒千粒重下降是导致减产的主要原因。去叶后直接导致玉米群体叶面积指数下降,无截取散射略微增加;保留3~4片叶处理,叶片光合性能表现出一定补偿效应,净光合速率高于对照处理,羧化效率略有升高;去叶处理降低灌浆后期子粒含水率,不保留穗位叶片处理较对照处理相比,在灌浆44、52、60 d,子粒含水率分别下降了8.14、8.75、17.84个百分点。     

打顶对芝麻不同叶位光合特性的影响研究

在大田管理条件下,以不打顶为对照,研究了打顶对芝麻不同叶位叶片光合特性的影响。结果表明：芝麻叶片在打顶后通过调节合适的气孔开度来控制对蒸腾强度的调节,使气体交换达到一个经济合理的阈值,从而提高光能利用效率(LUE)和水分利用效率(WUE)。打顶使芝麻各部位叶片蒸腾强度（Tr）和气孔导度（Gs）都同时下降,平均比不打顶的分别下降4.71%和8.81%,而光合速率和水分利用效率分别比不打顶的高出5.97%和13.96%。打顶与不打顶各叶位间比较,上、中、下三叶位叶片光合速率（Pn）、叶片光能利用效率、叶片水分利用效率、蒸腾强度和气孔导度都达极显著水平。打顶后,在生育后期中、下部叶位叶片仍具有较高的光合效率、光能利用效率与水分利用效率。     

Model predicting dynamics of biomass, structure and digestibility of herbage in managed permanent pastures. 1. Model description

To investigate seasonal and annual interactions between management and grassland dynamics, a simple mechanistic model of the dynamics of production, structure and digestibility in permanent pastures was constructed. The model is designed to respond to various defoliation regimes, perform multiple‐year simulations and produce simple outputs that are easy to use as inputs for a model of ruminant livestock production. Grassland communities are described using a set of average functional traits of their constituent grass groups. The sward is subdivided into four structural compartments: green leaves and sheath, dead leaves and sheath, green stems and flowers, and dead stems and flowers. Each compartment is characterized by its biomass, age and digestibility. Only above‐ground growth is modelled, using a light‐utilization efficiency approach modulated by a seasonal pattern of storage and mobilization of reserves. Ageing of plant parts is driven by cumulative thermal time from 1 January and by biomass flows. Age affects senescence, abscission and digestibility of green compartments and, therefore, the quality of green leaves and stems can increase or decrease over time in relation to net growth and defoliation dynamics. The functional traits having the greatest impact on model outputs are seasonal effects, period of reproductive growth and effects of temperature on photosynthetic efficiency. The functional traits of the grass groups were parameterized for temperate pastures of the Auvergne region in France. The other model inputs are few: proportion of functional groups, basic weather data (incident photosynthetically active radiation, mean daily temperature, precipitation and potential evapotranspiration) and site characteristics (nitrogen nutrition index, soil water‐holding capacity). In the context of a whole‐farm simulator, the model can be applied at a field scale.     

Effect of partial and complete defoliation on regrowth of white clover plants

Single plants of white clover (Trifolium repens) were subjected either to two intensities of overall defoliation or to severe defoliation of different parts of the plant. Measurements were made of growth in terms of leaf size, petiole length, internode length and other parameters, and compared with those of undefoliated plants. The results show that, while growth of all parts of the plant was reduced by severe overall defoliation, partial defoliation affected various parts of the plant differently according to which leaves were removed. The results are interpreted in terms of the acropetal movement of assimilates from alternative sources in response to defoliation. The probable effects of this on yield and its relevance to grazing management of newly seeded clover are discussed.     

芝麻硼素营养与硼肥应用——Ⅰ、施硼对芝麻生长发育、产量及品质的影响

多点田间试验及盆栽试验结果表明,淮北平原和长江中下游地区的砂姜黑土、黄棕壤及黄潮土,芝麻施硼增产幅度为1.1—33.7％,平均增产13.1％,其中底施硼肥平均增产10.8％,喷施平均增产17.8％ 施硼提高芝麻含油量,降低蛋白质含量;亚油酸显著增加,其它脂肪酸无明显变化。在缺硼的条件下,芝麻植株矮小,下部叶片增厚,倒卷,严重时植株生长受阻,顶端坏死。     

不同覆膜方式下超高产春玉米花粒期叶片衰老特性研究

以内单314为试验材料,在行间覆膜(SPF)、行上覆膜(UPF)及不覆膜(NPF)3种处理下,对超高产春玉米花粒期不同层位叶片的保护酶活性、光合特性及产量进行研究。结果表明,超高产春玉米花粒期不同层位叶片POD活性表现为下位叶>穗位叶>上位叶;CAT、SOD活性表现为上位叶>穗位叶>下位叶。灌浆期玉米不同层位叶片净光合速率、气孔导度、蒸腾速率变化趋势表现为穗位叶>上位叶>下位叶;乳熟期不同层位叶片净光合速率、气孔导度、蒸腾速率表现为上位叶>穗位叶>下位叶。表明在玉米花粒期,行间覆膜处理可以提高玉米上位叶及穗位叶的净光合速率、POD活性、CAT活性及SOD活性,减小气孔导度,降低叶片蒸腾速率,延缓叶片衰老,维持花粒期生理功能,保证子粒充分灌浆,提高千粒重,进而提高产量,实现超高产。     

控释氮肥调控水稻光合功能和叶片衰老的生理基础

 以杂交水稻组合八两优100和威优46为试验材料，探讨了控释氮肥对水稻光合功能衰退和叶片衰老的调控机制。结果表明，控释氮肥对延缓早、晚稻功能叶的衰老和延长叶片的光合功能期均具有明显的效应。与施用尿素的处理相比，施用控释氮肥后，早、晚稻生育中、后期功能叶中的叶绿素含量得到显著的提高，且与尿素间的差异随着水稻生育进程而增大。不同时期控释氮肥处理功能叶的净光合速率也均显著地高于尿素处理。此外，施用控释氮肥能显著地提高生育中、后期功能叶中的SOD、POD等活性氧清除酶的活性，降低功能叶中的丙二醛含量。施用控释氮肥对功能叶中的IAA、ABA含量具有明显的调控效果，早、晚稻各时期控释氮肥处理的IAA含量均显著地高于尿素处理，而ABA含量显著地低于尿素处理。由于控释氮肥对水稻的上述调控机理，因而，在水稻上施用控释氮肥可以明显提高水稻产量。     

Effect of defoliation and drought stress on yield components and chlorophyll content of wheat

In order to examine the effects of source restriction and drought stress on yield components, flag leaf chlorophyll content and Relative Water Content (RWC) of wheat cultivars, a greenhouse experiment was carried out at Shiraz University, Shiraz, Iran, during 2009-2010. The wheat cultivars including Shiraz, Bahar, Pishtaz, Sistan and Yavaros were sown in 5 kg plastic pots. The source manipulation treatments including control (C), defoliation of all leaves (D1), defoliation of all leaves except the flag leaf (D2) and defoliation of all leaves except the flag leaf and penultimate leaf (D3), were imposed at anthesis. Results showed that source restriction decreased number of grain per spike significantly in Shiraz cultivar under drought stress condition. Maximum 100-grain weight was observed in C treatment of Yavaros and Shiraz under well-watered condition. Among the defoliation treatments under drought stress condition, D2 in Pishtaz and D1 in Shiraz had the highest (3.66 g) and lowest (2.71 g) 100 grain weight, respectively. In all cultivars drought stress decreased main shoot yield significantly but in Pishtaz and Sistan decreasing rate was less than the other cultivars. RWC in Shiraz decreased sharply from 92.1% in well-watered to 66.7% (27.5% reduction) under drought stress at 10 DAA. After anthesis, Pishtaz and Sistan maintained higher content of flag leaf chlorophyll (from 49.4 to 56.8 SPAD unit) under drought stress condition. Generally, selection and culture of cultivars that had small responses to defoliation might be a useful strategy in yield improvement of wheat in areas where the water availability is low.     

Physiological Basis of Photosynthetic Function and Senescence of Rice Leaves as Regulated by Controlled-Release Nitrogen Fertilizer

The physiological mechanism of photosynthetic function and senescence of rice leaves was studied by using early rice variety Baliangyou 100 and late rice variety Weiyou 46, treated with controlled-release nitrogen fertilizer （CRNF）, urea and no nitrogen fertilizer. CRNF showed obvious effects on delaying the senescence and prolonging photosynthetic function duration of rice leaves. Compared with urea, CRNF could significantly increase the chlorophyll content of functional leaves in both early and late rice varieties, and this difference between the treatments became larger as rice growth progressed; CRNF increased the activities of active oxygen scavenging enzymes super oxide dismutase （SOD） and peroxidase （POD）, and decreased the accumulation amount of malondialdehyde （MDA） in functional leaves during leaf aging; Photosynthetic rate of functional leaves in CRNF treatment was significantly higher than that in urea treatment. The result also indicated that CRNF could effectively regulate the contents of indole-3-acetic acid （IAA） and abscisic acid （ABA） in functional leaves; IAA content was higher and ABA content was lower in CRNF treatment than those in urea treatment. Therefore, application of CRNF could increase the rice yield significantly due to these physiological changes in the functional leaves.