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1.
多效唑(PP333)对大豆增产作用和生理效应的研究   总被引:3,自引:0,他引:3  
多效唑是一种新型植物生长延缓荆,经过两年试验结果表明,在大豆盛花期喷施,可以使植株高度显著降低,喷施后8d可降低16~20cm,成熟期可降低40—41cm,同时也可使结荚高度降低12~13cm,而且植株抗倒伏能力增强,但对植株主茎节数没有明显影响。喷施多效唑可以显著增加产量,增产幅度为17%-18%,光合效率增加29%左右。增产的生理效应主要是使植株叶片叶绿素含量增加和光合效率提高,可增加单株粒数和荚数,粒重提高,最终提高产量。  相似文献   

2.
In two experiments (1990 and 1991) perennial ryegrass (cv. Talbot) pasture was subjected to six different management treatments by adjusting stock numbers to achieve set sward heights for set periods between turn-out in early April and weaning in early July. The main objective of the experiments was to measure the effect of differences in sward management up to July on subsequent sward type, and the effect of sward type on the performance of weaned lambs between mid-July and early October when all swards were grazed at a sward height of 7 cm. In Experiment 1 swards were grazed at 7 cm initially and then reduced to 3 cm at various dates and maintained at 3 cm until early July. In Experiment 2 swards were grazed initially at 7 cm, and this was reduced to 3 cm and then allowed to return to 7 cm at various dates up to early July. Grazing at a sward height of 7 cm up to weaning, in early July, gave mean twin lamb growth rates of 310 g d?1, while at a tower sward surface height of 3 cm lamb growth rate was reduced to 206 g d?1 The density of seed heads produced from July was strongly influenced by earlier management. Grazing at 7 cm up to July gave a high density of seed heads (213m?2), and this reduced (126 m?2) by grazing to 3 cm. Seed heads were almost eliminated (17 m?2) by grazing at 7 cm until late June followed by grazing down to 3 cm in early July. Reducing sward surface height from 7 cm to 3 cm at an earlier date tended to increase the development of seed heads from early July. Where swards were grazed from 7 cm to 3 cm and then allowed to return to 7 cm, the later in the pre-weaning period this took place the greater the reduction in seed head development. Greater seed head density was associated with a significant decrease in the nitrogen content of the herbage on offer in Experiment 2, but an increase in modified acid detergent (MAD) fibre content was not significant. Despite the differences in the sward type on offer, the effect on weaned lamb growth rate was small. Lamb liveweight gain during autumn was significantly reduced in Experiment 2 following earlier grazing at 7 cm compared with 3 cm, but liveweight gain differences in Experiment 1 were not significant.  相似文献   

3.
为探究不同灌溉策略下冬小麦水分利用和生长的情况,在总灌溉量相同的前提下设置拔节水+开花水单次参比蒸散30%灌溉(W1)、拔节水+开花水单次参比蒸散60%灌溉(W2)和拔节水+开花水大水漫灌(W3)3种灌溉策略,利用称重式蒸渗仪和diviner 2000研究了不同灌溉策略下冬小麦的耗水动态、蒸散特征和水分利用效率。结果表明,大水漫灌处理(W3)下冬小麦主要利用上层(0~50 cm)土壤水分,而低速率灌溉(W2和W1)处理增强了植株根系对深层(70~100 cm)土壤水分的吸收;同时,低速率灌溉可以降低蒸散速率,W3、W2和W1的日蒸散速率最大值在拔节水灌溉期间分别为13.20、10.82和10.58 mm·d-1,在开花水灌溉期间分别为15.10、10.57和9.10 mm·d-1,其中低速率灌溉主要降低了单日蒸散的午间高峰值,减少了无效耗水。大水漫灌处理不利于生长后期株高的增加,而低速率灌溉不仅有利于株高的形成,也有利于叶片维持较高水平且稳定的SPAD值,保证了籽粒灌浆,使得W2处理的穗粒数和千粒重较W3处理分别提高7.25%和3.93%。综合来看,低速率灌溉策略通过低量持续的供水改变了冬小麦植株根系对土壤水利用的层次,减少无效水蒸散,维持叶片稳定的光合能力,提高了产量和水分利用效率。  相似文献   

4.
茶树种苗工厂化快速繁育技术   总被引:5,自引:1,他引:4  
本文在全自动智能化温室内,按组培+温室培育和直接温室扦插培育两条技术路线,采用不同材料进行了茶树工厂化育苗试验。结果表明,以田间材料为组培起始物时,春季新梢第三腋芽萌发率最好,每周期增殖率可达2.75倍左右,成苗率在20%以上,直接移植生根率为成活小苗的90%左右。一年双季育苗试验表明,春夏季育苗在3月中旬开始,5个月后,茶苗高度达20.4±8.3βcm,练苗后移栽成活率近100%;秋冬季育苗在8~9月初开始,冬季完成根系建立,开春后达20βcm以上高度,练苗后移栽;施肥处理茶苗高度的增加量是不施肥对照的5.9倍。  相似文献   

5.
Measurements of rates of growth and senescence of leaf lamina per tiller and of changes in tiller population densities were made in three experiments designed to investigate the influence of sward slate on leaf turnover and net production under continuous stocking. In each experiment initially uniform swards were fenced to provide four plots on which animal numbers were adjusted twice weekly to give a series of swards maintained as nearly as possible in a steady state with respect to sward surface height (range 1.1–6.4 cm) and herbage mass (range 440–2690 kg OM ha?1). Two experiments were carried out in July–September on vegetative swards and one in May–June on a reproductive sward. Measurements were begun 3–7 weeks after treatments were started and were repeated weekly during 3–4 week measurement periods. In all three experiments the rate of lamina growth per tiller increased linearly with an increase in sward surface height and herbage mass. In the two experiments conducted in July–August this relationship was partially offset by a linear increase in the rate of senescence per tiller but net production per tiller also increased linearly in relation to sward height and mass. In the experiment conducted in May–June the rates of growth and senescence per tiller increased in parallel so that net production per tiller showed no relationship with sward condition. Tiller population densities in the July–August experiments were highest in swards maintained between 2 and 3 cm surface height and declined in swards maintained above and below this height. In the experiment in May–June tiller numbers were similar in all treatments prior to the summer solstice but diverged in a manner similar to the other experiments later in the year. The rate of lamina growth per unit area increased in a manner consistent with an asymptotic relationship and the rate of senescence increased linearly with increasing sward height and mass in all three experiments. Net production per unit area was reduced on swards below about 2.5 cm in height but was insensitive to variation in sward surface height between 2.5 and 6.0 cm (approximately 1000–2500 kg OM ha?1 herbage mass). The effectiveness of adjustments in tiller numbers and production per tiller and of changes in the balance between growth and senescence as mechanisms of sward homeostatis, together with their implications in the scope for manipulating herbage production by grazing management are discussed briefly.  相似文献   

6.
以云蔗07-2800为材料,在收获期设置4个不同铲蔸深度(5、0、-5、-10 cm),研究不同铲蔸深度对甘蔗伸长期根系形态特征和生理特性的影响。结果表明:铲蔸深度对伸长期甘蔗生物量有极显著影响(P<0.01)。铲入地下5 cm处理甘蔗伸长期地上部生物量干重极显著高于其他处理,各处理间根冠比差异较大。在伸长期甘蔗总根长、根系总表面积和根系总体积均呈现增长趋势,且在伸长中期和后期,铲入地下5 cm处理的总根长、根系总表面积和根系总体积均极显著高于其他处理。同一时期各处理根系丙二醛(MDA)含量高低表现为5 cm>-5 cm>0 cm>-10 cm,根系超氧化物歧化酶(SOD)和过氧化物酶(POD)活性高低总体表现为伸长后期>伸长中期>伸长早期。根系超氧化物歧化酶(SOD)、过氧化物酶(POD)和硝酸还原酶(NR)酶活性高低均表现为5 cm<0 cm<-5 cm<-10 cm的趋势。蔗蔸铲入地下5 cm处理的甘蔗生物量最大,产量最高,说明该处理可有效促进宿根甘蔗根系生长、发育,增加深层根系总量,提高根系抗逆性生理指标含量与活性,提高甘蔗植株对水分、养分的利用效率,增产增效。在甘蔗机械化管理收获技术水平不断提高和宿根蔗年限不长的背景下,宿根蔗采用入土5 cm铲蔸作业,具有较好增产效果和大面积推广应用的前景。  相似文献   

7.
Rotational stocking (RS) is generally associated with the intensification of pasture-based animal production systems, although many studies have shown little advantage over continuous stocking (CS). The objective of this research was to describe and explain the effects of two average canopy heights (20 and 30 cm) and three stocking methods (CS; rotational stocking with lenient defoliation, RSL; and rotational stocking with moderate defoliation, RSM) on forage accumulation (FA), vertical distribution of plant-part components, and nutritive value of ‘Mulato II’ hybrid brachiariagrass (Brachiaria spp. syn. Urochloa spp.) during two summer rainy seasons in Piracicaba, São Paulo, Brazil. Pastures were maintained at average canopy height of 20 and 30 cm under CS, and treatments under RSL and RSM were imposed by variations of ±20 and 30% of the average canopy heights, representing defoliation intensities of 33 and 47% of the pre-graze heights, respectively. The FA was not affected by CS, RSL, RSM stocking methods, averaging 8090 kg DM ha−1 year−1. Canopy bulk density and distribution of plant-part components in the canopy profile were better at the average canopy height of 20 cm, accompanied by the greater nutritive value. The leaf bulk density was generally greater in RSM compared to CS. Pastures under CS had greater crude protein and in vitro digestible matter, and lesser neutral detergent fibre concentrations. Mulato II brachiariagrass should be managed at an average height of 20 cm under CS.  相似文献   

8.
A field study was conducted at Al-Mishkhab Rice Research Station (MRRS) during the summer season 2009 to evaluate irrigation water use efficiency (IWUE) using Anbar 33 variety with the System of Rice Intensification compared to traditional methods. During the growth phase, the number of leaves, stems, and roots, and the average plant height were measured every 15 days for the two sets of methods. At maturity, the depth and length of plant roots was assessed, along with leaf area index (LAI) of the flag leaf and plant height. The amount of irrigation water applied was measured by water meter for both methods. SRI principles for plant age, spacing, etc., were implemented in the SRI plots. The results indicated more vigorous growth of roots under SRI methods, reaching 13,004 cm plant−1 compared with non-SRI results of 4,722 cm plant−1. There was 42% increase in grain yield when SRI methods were used. These had water use efficiency (WUE) of 0.291 kg m−2 compared with WUE of 0.108 kg m−2 for non-SRI cultivation, almost a threefold difference. SRI practices reduced the need for irrigation water by 38.5%.  相似文献   

9.
Ninety-six plots (3 × 2 m) of well-established perennial rye grass/white clover pasture were mown to heights of 2·7 (Low) or 3·96 (High) cm (rising plate meter) at 14-, 28-, 84- or 112-d intervals in autumn-winter. A 7-, 14- and 28-d mowing interval was superimposed in spring on each autumn–winter mowing interval treatment with the low and high mowing heights altered to 2·92 and 4·80 cm, respectively.
With the low cutting height, accumulated herbage DM was more than doubled (1806 ± 79 kg DM ha-1) compared to a 'high' (754 ± 49 kg DM ha-1) cutting height in autumn–winter and this was due to increased harvesting efficiency rather than growth as estimated by leaf extension. Although defoliation interval had no effect on DM yield, the grass component increased and clover decreased. The composition effect carried over into spring. On average, 3·5 tillers were produced over winter for each ryegrass tiller present in autumn and tiller densities were higher in spring. Tillers produced over autumn–winter contributed more than 60% of ryegrass growth by early spring.
In early spring (16–30 September), the low cutting height increased herbage DM yield, in mid-spring (1–14 October) it reduced DM yields particularly in combination with short defoliation intervals, while in late spring (14 October to 11 November) cutting height had no effect on DM yields.
Over the entire spring period there was a very marked effect of defoliation interval on DM yields.  相似文献   

10.
为了探索解决杂交小麦制种中父母本株高相近组合的制种问题,于小麦品系始穗期(抽穗5%)时用30g.hm-2的赤霉素处理1 594份小麦种质,结果表明,绝大多数小麦种质的株高对赤霉素不敏感,1 594份供试品系中仅60份品系的株高对赤霉素敏感。由于部分品系来自同一种质的后代,小麦种质株高对赤霉素的敏感率实际上不到1%。赤霉素敏感的小麦品系株高增加范围为5~39cm,其中Haida42-6-30和周麦13-2-1-1-3两个品系株高与对照差异极显著,用赤霉素处理后株高增加35cm以上,可作为培育杂交小麦父本的种质。  相似文献   

11.
Cutting patterns producing high and low areas were imposed on swards of Dactylis glomerata and Lolium perenne to test whether output could be increased when compared with traditional uniform cutting methods. In two experiments, swards of both grasses were divided into parallel 9 cm strips which were cut alternately on different occasions to a height of 5 cm. These swards yielded a similar quantity of herbage DM to that from other swards cut uniformly at the same height and frequency. In a third experiment, swards of Lolium perenne were divided into alternate strips of unequal width (9 and 4.5 cm). The narrow strips were allowed to grow to a height of 15 cm and were occasionally trimmed at this height. The wide strips were cut to 5 cm at 2–or 4–weekly intervals. Areas cut to 5 cm every 2 weeks yielded significantly more DM when adjacent to high areas than when adjacent to areas cut to 5 cm every 2 weeks (i.e. under uniform cutting). The interaction between adjacent areas having different defoliation regimes is discussed in relation to the possibility of obtaining some additional output from a suitable no niform cutting system compared with uniform cutting. Sward productivity under no niform grazing patterns of livestock is also discussed.  相似文献   

12.
为给优质高产小麦的育种和栽培建立茎型指标体系,2002~2003年度和2003~2004年度分别以不同蛋白质含量类型的小麦品种(系)71个和94个为供试材料,测定了株高、各节间长度、籽粒蛋白质含量和产量,研究了不同蛋白质含量类型小麦的株高和各节间长度等茎部性状的差异及其与产量的关系.结果表明,高蛋白质含量类品种的株高、倒2节间长和倒3节间长显著大于低蛋白质含量类型品种;高蛋白高产类型小麦的适宜株高、穗下节间长、倒2节间长和倒3节间长分别为85~107 cm、27 cm 以上、23 cm左右和14 cm左右,在适宜范围内以各项值稍大较为理想;低蛋白质含量、高产类型的品种则分别为85 cm以下、30 cm 以下、18.5 cm左右和12 cm左右,在适宜范围内各项值以稍小较为理想.  相似文献   

13.
华南双季超高产水稻抽穗期理想株型结构研究   总被引:12,自引:0,他引:12  
 对华南稻区新育成的超高产杂交稻组合粤杂122、丰优428、泗优998、培杂67和超高产常规稻品种广超3号、胜泰1号等6个材料抽穗期的主要形态性状进行了差异显著性测验及对产量的通径分析,提出了华南双季稻超高产育种抽穗期理想形态指标分别为:早季株高90~105 cm;每蔸茎数11~12条;剑叶长35~40 cm;剑叶宽2.1~2.2 cm;倒2叶长、宽为46~50 cm和1.8~2.1 cm;倒3叶长、宽为59~64 cm和1.4~1.9 cm;剑叶开张角7~14;倒2叶、倒3叶开张角为18 和20~33。晚季株高95~100 cm;每蔸茎数9~15条;剑叶长30~41 cm;剑叶宽1.8~2.0 cm;倒2叶长、宽为53~61 cm、1.3~1.8 cm;倒3叶长、宽为52~58 cm、1.2~1.5 cm;剑叶开张角9 ~19;倒2叶、倒3叶开张角为15~37、16~49。同时测定了参试材料的主要生理性状,并对华南双季稻超高产育种抽穗期的适宜生理指标进行了探讨。  相似文献   

14.
应用低含油量甘蓝型油菜品系1064与高含油量品系H105杂种F1花蕾进行小孢子培养,研究了两个种植地点的油菜小孢子产胚率的影响。对长度在0.4cm~0.6cm,0.6cm~0.8cm以及0.8cm以上的胚分别培养,并比较了秋水仙碱悬浮处理离体小孢子、浸根和滴芽3种染色体加倍方法的加倍效率。结果表明,种植在西宁的材料小孢子产胚率比南京高,为8.6枚/皿;0.6cm~0.8cm大的胚转接到B5固体培养基,其成苗率高达48.53%;3种加倍处理方法中以50mg/L秋水仙碱悬浮小孢子48h染色体加倍效率最高,达到46.23%。本研究构建了含有123个株系的DH群体,可用于油菜含油量性状的QTL分析。  相似文献   

15.
The contribution of four classes of sward height to daily herbage growth rates of a heterogeneous sward in eight periods throughout a grazing season was investigated in two continuous cattle-grazing systems differing in intensity (moderate stocking rate: MC; lenient stocking rate: LC). At the beginning and end of periods of 12 to 28 d, the compressed sward height (CSH) was measured in exclusion cages at eighteen fixed points per cage to derive daily growth rates for the four classes of sward height. Stratified calibrations were made to relate sward height to herbage mass for each treatment in each period. Quadratic regressions described the relationship between herbage growth rate and initial CSH for each treatment in each period. For scaling up to the scale of the plot, CSH was measured monthly at 100 points per plot. Daily herbage growth rates declined from more than 100 kg dry matter (DM) ha−1 d−1 on both treatments at the beginning of the grazing season to 20 kg DM ha−1 d−1 or less, especially on treatment LC. This was due to the larger area covered by tall herbage on treatment LC than on treatment MC. On treatment MC, daily herbage growth rate was predominantly derived from short sward areas of up to 12 cm in height while sward areas taller than 12 cm contributed most to daily growth rates on treatment LC in early summer. The method used is considered suitable for estimating daily herbage growth rates of different classes of sward height in extensively managed pastures and can easily be adapted to deal with more heterogeneous swards than used in this study.  相似文献   

16.
以玉米花丝为材料,采用苯胺蓝染色法检测授粉后玉米花粉管的伸长进程。授粉0.5 h后开始每隔1 h对花丝取样,直至48 h;所取花丝经固定、软化和苯胺蓝染色后压片,在倒置荧光显微镜紫外光滤片下观测花粉管伸长情况。结果表明,花粉在授粉后0.5 h就开始萌发,随后花粉管开始伸长并逐渐加速,3 h后以较高速度0.8~0.9 cm/h伸长,维持17 h后速度开始下降,22 h后大部分进入子房,整个过程中花粉管的平均伸长速度为0.68 cm/h。玉米花粉离体自然条件下的生命时间为5 h,此后开始分解。在玉米花粉介导转基因时需对离体的花粉与外源基因进行处理,这个过程消耗花粉部分内容物和能量,且影响花粉的活力,是玉米花粉介导法转化率偏低的一个重要原因。  相似文献   

17.
This study aimed to evaluate the efficacy of semi fermented and non fermented Camellia sinensis extracts (Black and Green tea) and comparison between them against Streptococcus mutans ATCC 25175, S. mitis ATCC 9811 and S. sanguis ATCC 10556 that are responsible for dental caries and bacteremias following dental manipulations. Minimum inhibitory concentrations of both tea extracts were assessed by Well diffusion and Broth dilution methods and examination of cell adherence (Biofilm inhibitory concentrations) was observed on glass slides under phase contrast microscope and colony counts from glass beads. Concentration of 1 mg mL(-1) of semi fermented tea extract was completely biofilm inhibitor but biofilm formation by these bacteria was seen 7 days after treatment with 1 mg mL(-1) of non fermented Camellia sinensis on glass beads and BIC for oral streptococci treated with this extract was 1.5, 2.5 mg mL(-1) of semi fermented and 3 mg mL(-1) of non fermented extracts had bactericidal effect on these bacteria. Semi fermented and non fermented Camellia sinensis extracts were able to prevent growth of oral streptococci. Therefore dental caries significantly reduce and the efficiency of semi fermented tea was higher due to rich content of volatile components rather than non fermented extracts.  相似文献   

18.
The objective of this study was to compare the grazing efficiency of 30 perennial ryegrass varieties, differing in ploidy and heading date. Plots were grazed by lactating dairy cows and managed under a rotational grazing system with 19 grazing events occurring over two years. Pre-grazing and post-grazing compressed sward heights were measured with a rising plate meter. A mixed model was used to predict the post-grazing sward height of each variety based on year, grazing event, block and pre-grazing sward height. Residual grazed height (RGH) was derived as the difference between the actual and predicted post-grazing sward height and was used as the measure of grazing efficiency. Negative RGH values indicated that the actual herbage removed was greater than that predicted and so indicated a superior grazing efficiency. Varieties differed in their level of grazing efficiency (p < .001), with RGH values ranging from −0.38 to +0.34 cm. Tetraploid varieties exhibited significantly greater grazing efficiency performance than diploids (p < .001), with average RGH values of −0.13 and +0.13 cm respectively. A significant difference in grazing efficiency was found among recommended perennial ryegrass varieties that are not being recorded by mechanically harvested simulated grazing protocols. A variety reappraisal that included grazing efficiency could identify varieties capable of improving on-farm livestock productivity from grass.  相似文献   

19.
Abstract Four sward height treatments were imposed by continuous variable stocking using at least ten Suffolk × Greyface lambs per plot from late July to late August: constant 3·5 cm. constant 6·0 cm. 3·5cm increasing to 6·0 cm and 6·0 cm decreasing to 3·5 cm. The treatments were established on two swards given fertilizer N applications over the season of 97 and 160 kg N ha?1 respectively. Animal density was greater on the high fertilizer treatment, at the lower sward height and especially on the decreasing height treatments. Liveweight change of lambs was higher (P <0·001) on the 6-cm than on the 3·5-cm treatments (+159 vs-13g d?1 and was also higher (P <0·001) on the increasing than on the decreasing sward height treatments (+92 vs-26 g d?1). Herbage organic matter intake (OMI), measured on two occasions in the experiment, was greater (P <0·001) on the 6·0 cm than on the 3·5-cm sward heights whereas values for the increasing sward height treatments were much greater than those for the decreasing sward height treatments. There was little difference in the organic matter digestibility of the diet between treatments. Diets were composed largely of lamina, although there was more pseudostem and dead herbage in the diets of Iambs grazing the decreasing than the increasing sward height treatments at the end of the experiment. Bite mass was closely related to OMI but the treatment and period differences were relatively greater than for OMI. Bite mass was more closely related to the depth of the lamina layer (sward height-pseudostem height) than it was to sward height. There was evidence that pseudostem acted as a barrier to defoliation on these short swards and also that the proportion of youngest leaf in the diet was positively related to sward height and to increases in sward height. Sward height and especially the direction of change in sward height, together with associated stock density, were potent influences on lamb growth rate. This was a consequence of differences in herbage intake, which was strongly influenced by bite mass.  相似文献   

20.
Some studies have shown that catecholamines and the changes in their levels during and after head trauma can be useful in predicting the outcome in head trauma patients. The goal of this study is to search for a probable relation between urine levels of catecholamines and prognosis in patients with severe head trauma. Fifty four patients with severe head trauma Glasgow Coma Scale (GCS < or = 8) on admission time were recruited in Imam Reza Hospital within one. These patients were included when having no major accompanying trauma in other organs. Twenty four hour urine was collected after admission and levels of metanephrine and nor-metanephrine were measured. The relation between urine levels of these metabolites with final outcome and also with GCS at admission, 24, 48 h and 1 week after admission and discharge time and Glasgow Outcome Scale (GOS) were studied. Fifty two patients, 48 males and 4 females with a mean age of 32.3 +/- 14.7 (3-72) years were included. The main underlying etiologies were motorcycle (46.2%) and car accidents (25%). Diffuse axonal injury, brain contusion and subdural hematoma were three main diagnoses (28.8, 17.3 and 15.4% of the cases, respectively). 19 (36.5%) of the patients expired within the study period. The mean level of metanephrine and normetanephrine in urine were 207.9 +/- 200.5 and 330.2 +/- 218.4 microg in 24 h, respectively. There was no meaningful relation between urine levels of these metabolites and any of GCS and GOS. There was also no meaningful relation between these parameters and final prognosis in patients.  相似文献   

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