花生叶片衰老的初步研究

高产花生品种鲁花１１号和辐８７０７叶片衰老的研究结果表明,花生叶片展开至衰老过程中,叶绿素含量、净光合速率（Ｐｎ）、可溶性蛋白质（Ｐｒ）含量先升高,至最大值后缓慢下降,到衰老后期转为快速下降,呈抛物线变化,可分为叶片缓衰期（叶片展开后２５￣３０ｄ至５５￣６０ｄ,各指标从最大值至降到最大值的５０％）和叶片速衰期（叶片展开５５￣６０ｄ以后,各指标从最大值的５０％至叶片脱落）两个变化阶段。两品种相比,辐     

Note on relationship between leaf soluble carbohydrate and chlorophyll concentrations in maize during leaf senescence

Leaf senescence is typically associated with loss of chlorophyll and decline in photosynthetic capacity. The objectives of this study were: (i) to quantify the relationship between chlorophyll (SPAD) and soluble-carbohydrate concentrations in maize (Zea mays L.) leaves during leaf senescence and (ii) to examine whether this relationship differed between an old and a recent maize hybrid. Field experiments were conducted in 1995 at two locations. A range of leaf soluble-carbohydrate concentrations and SPAD values was obtained through various source-manipulation of source activity by defoliation and thinning. Defoliation treatments were imposed at 3, 4, and 5 weeks after silking. The thinning treatment was imposed at 3 weeks after silking. Two maize hybrids were composed: Pride 5 (old) and Pioneer 3902 (recent). Leaves at three leaf positions, near the topmost ear and the ear internode were sampled at weekly intervals, from 3 weeks after silking until visual completion of leaf senescence. Leaf and internode soluble-carbohydrate concentration declined following defoliation, although the response in leaves was delayed compared to that in the stem. SPAD readings and soluble-carbohydrate concentrations were positively correlated below a plateau value of 55 mg glucose equivalents g⁻¹ leaf. The correlation between SPAD and soluble-carbohydrate concentration was similar for the old and recent maize hybrid.     

A model of leaf area development and senescence for winter oilseed rape

In winter crops, leaf area is a major determinant of the final yield, and is substantially affected by losses occurring during vegetative growth. Here, we propose and test a submodel simulating the development of leaf area and pod area, along with leaf senescence, for winter oilseed rape (Brassica napus L.), which was included in a CERES-type model for rape adapted from CERES-N Maize. This crop model, called CERES-Rape, has components for crop phenology, net photosynthesis, N uptake, and assimilate partitioning. As a new feature compared to previously published work, the leaf area submodel includes senescence from shading due to competition for light in the canopy, and from leaf N deficiencies. The model has been developed and parameterised on a 1-yr-long experiment with three fertilizer N treatments in northeastern France, during which measurements of senescing parts allowed calibration of the equations for leaf area index (LAI) senescence and total generated LAI. The leaf area submodel, once coupled to the CERES-Rape model, was tested against two additional experiments from Denmark and northern France. This process-oriented submodel proved accurate for the simulation of actual LAI whether in the calibration or in the validation phase, with an overall Root Mean Square Error (RMSE) of 0.496 m² m⁻², falling close to the mean experimental standard deviation. Extrapolation did not require any further adjustment, although a different cultivar was involved.     

油菜叶片自然衰老过程中部分生理指标的变化规律

以双低油菜品种H165为供试材料,测定了油菜长柄叶和短柄叶自然衰老进程中的部分生理指标.试验结果表明,长柄叶和短柄叶伸展期间,叶绿素含量、细胞分裂素含量、SOD酶活性和MDA积累量均相对稳定并略低于基本定型叶片;叶片基本定型后,叶绿素含量、细胞分裂素含量和SOD酶活性呈明显的下降趋势,MDA积累量则大幅度上升.虽然总体变化趋势基本一致,但长柄叶中叶绿素含量、细胞分裂素含量和SOD酶活性下降幅度明显大于短柄叶,MDA积累量的上升幅度则略高于短柄叶.     

Relationship between grain filling duration and leaf senescence of temperate rice under high temperature

High temperature during grain filling period has been reported to decrease the grain filling duration, leading to the lower grain weight and yield of rice. Two experiments in the phytotron and field were carried out to test the hypothesis that the leaf senescence of rice plants may determine the grain filling duration under high temperature. In the phytotron experiment in 2008, rice plants of a japonica cultivar “Ilpumbyeo” were subjected to three minimum/maximum (mean) temperature regimes of 11/19 (15), 17/25 (21), and 23/31 °C (27 °C). In the field experiment, rice seedlings of the same rice cultivar were transplanted on May 6th and June 19th in 2009 and the mean temperatures during the grain filling period were 24.4 and 21.9 °C, respectively. Both experiments revealed consistently that high temperature increased the rates of grain filling and leaf senescence while it reduced the durations of them. However, grain filling was terminated earlier than complete leaf senescence, the time gap being greater at higher temperature. In addition, the fraction of dry matter partitioning to the leaf sheath + culm resumed to increase following the termination of grain filling under high temperature, indicating that leaves were still maintaining photosynthetic capacity and supplying assimilates into the other plant tissues except grain even after the termination of grain filling. These findings suggest that an early termination of grain filling in temperate rice under high temperature was not resulted from the lack of assimilate owing to the early leaf senescence but from the loss of sink activity owing to the earlier senescence of panicle.     

花生不同衰老型品种叶片衰老过程中多胺变化规律的研究

在大田条件下以两个不同衰老型花生品种为材料,研究了叶片衰老过程中多胺的变化。结果表明：内源多胺与叶片衰老密切相关,随叶片展开、成长到衰老,叶片多胺总量的变化是先上升后下降,幼嫩叶片多胺含量早衰型高于正常衰老型,但在叶片衰老过程中,早衰型叶片多胺含量下降速度快、幅度大,其含量低于正常衰老型,从多胺组成上,花生叶片中共检测出三种多胺,其中腐胺所占比例最大。     

茶小卷叶蛾及其生物防治

本文简要介绍了茶小卷叶蛾的基本特性及其防治措施，尤其重点介绍了生物防治的方法。生物防治能有效防治小茶卷叶蛾的同时又能克服农残、抗药性、环境污染等问题，是无公害茶叶的生产有效措施。     

Drought stress and tropical maize: QTLs for leaf greenness, plant senescence, and root capacitance

Genetically improved crops with higher water productivity help maintaining and increasing agricultural production in drought-prone areas. Their development involves, as in the case of maize, selection for high grain yield and improved secondary traits. With the objective of better understanding the role and regulation of the morphology of drought adaptation, a recombinant inbred line (RIL) population of tropical maize (Zea mays L.) was evaluated in six field experiments under intermediate (IS) and severe (SS) drought stress at flowering and under well-watered (WW) conditions in Mexico. The analyses per water regime revealed 32 quantitative trait loci (QTLs) for the five measurements of relative content of leaf chlorophyll (CL), 25 for the five visual ratings of plant senescence (SEN), and 11 for the three measurements of electric root capacitance (RCT). Impressive clusters of QTLs were observed on chromosomes 2 (bins 2.03-05), 4 (bin 4.09), and 10 (bins 10.04-05), suggesting that a small number of genes control chlorophyll metabolism and plant senescence. The high CL and low SEN of the drought resistant parent are aspects of its high water productivity resulting from improved constitutive traits. Co-locations of QTLs for CL, SEN and RCT with QTLs for plant height (PHT), the anthesis-silking interval (ASI), and grain yield (GY) were observed in bins 1.06-07, 8.06, and 4.09 but not for the large QTL clusters on chromosomes 2 and 10, suggesting independent genetic control of reproductive traits. Still, the phenotypic data showed that high CL and low SEN were favorable for grain yield production under drought, while delayed SEN was associated with higher grain yield under WW conditions. CL and SEN are suitable to complement selection for drought tolerance in order to sustain future breeding progress.     

Responses of photosynthetic characteristics and leaf senescence in summer maize to simultaneous stresses of waterlogging and shading

A field experiment was performed to investigate the physiological mechanism of the simultaneous stresses of waterlogging and shading on leaf photosynthetic and senescence during three growth stages of summer maize. The responses of leaf gas exchange parameters and antioxidant enzyme activities of the summer maize hybrids Denghai 605(DH605) to waterlogging(W), shading(S), and their combination(W + S) for 6 days at the third leaf stage(V3), the sixth leaf stage(V6), and the tasseling stage(VT) wer...     

生长调节物质对花生叶片衰老调控的初步研究

结荚期喷施０．０１ｍＭ赤霉素,０．０５ｍＭＮ＾６－苄基腺嘌（６－ＢＡ）,５ｍＡ脯氨酸,３ｍＭ抗坏血酸,１０ｍＭ甘氨酸,６ｍＭ乙烯利等生长调节物质均可提高花生叶片叶绿素含量和净光合速度,增加叶片可溶性蛋白持含量,降低叶片内丙二醛积累量,提高叶片超氧化物歧化酶,过氧化物酶和过氧化氢酶活性,延缓花生叶片衰老,提高产量。     

节水栽培条件下不同粒叶比小麦的光合性能研究

为给小麦节水高产、超高产栽培提供依据,在节水条件下,分析了不同粒叶比类型小麦品种旗叶与非叶器官光合性能的差异及其与粒叶比的关系.结果表明,高粒叶比品种旗叶面积小,灌浆期叶面积衰亡慢,光合功能期长,光合速率高,在灌浆后期非叶器官光合速率甚至高于叶片.同时发现,穗面积、旗叶节以上非叶器官(穗、穗下节间、旗叶鞘)面积与穗粒重均呈显著正相关,叶片、茎秆、叶鞘、穗颖贮藏物质的转移率与粒叶比均呈显著或极显著正相关.因此,通过育种或栽培技术提高粒叶比,充分利用并强化非叶器官光合机能,是实现节水高产、超高产的重要途径.     

油菜短柄叶光合衰退及其对产量的影响

以中双9号、中油杂11号和华油杂14号油菜为材料,测定花后短柄叶光合速率及生理指标,探讨短柄叶光合衰退与叶绿素含量等因素之间的关系及其对油菜产量的影响。结果表明,油菜短柄叶光合速率随叶片衰老而逐渐降低,1,5-二磷酸羧化酶(RuBPCase)、可溶性蛋白和叶绿素含量,以及超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性均呈现出下降趋势,膜脂过氧化作用产物丙二醛(MDA)在叶片光合功能衰退过程中含量逐渐上升。油菜叶片光合衰退与RuBPCase含量、可溶性蛋白含量、叶绿素含量和SOD活性存在显著相关关系,表明光合速率的下降可能与油菜叶片衰老过程中N含量、叶绿素降解及蛋白质合成受抑制相关;SOD和CAT水平逐渐降低及MDA含量升高也表明,叶片衰老过程中氧自由基胁迫抑制光合作用。叶片光合作用与油菜单株产量的相关关系分析结果表明,油菜短柄叶光合速率,特别是短柄叶衰退的中后期光合速率是影响油菜产量的重要因素。     

Exogenous abscisic acid coordinating leaf senescence and transport of assimilates into wheat grains under drought stress by regulating hormones homeostasis

Drought at the grain filling stage of wheat will cause premature leaf senescence, thus leading to consid-erable loss of wheat yield. Therefore, this paper aims ...     

Growth rate, senescence and photosynthesis of ryegrass swards cut to maintain a range of values for leaf area index

An experiment was carried out in which simulated swards of ryegrass (cv. S23) were grown in boxes. In the first instance the swards were cut at weekly intervals to maintain five levels of leaf area index (LAI) from LAI 1 to 4–5 in simulation of continuous grazing. Measurements were made of growth, senescence and net growth rate and of net canopy photosynthesis at constant irradiance. The results showed that the swards adapted to the defoliation regimes mainly by changes in tiller population density and pseudostem length. When the swards had equilibrated to the cutting regime growth rate increased with LAI but, since tiller density and the partitioning of growth between herbage harvested and that lost by sensecence also changed with LAI, net growth rate was constant over the LAI range 2–4·5. Maximum weight of herbage harvested was obtained between LAI 2 and 3.
After 10 weeks of weekly cutting all the swards were cut back to LAI 1 and allowed to regrow. Growth rate showed almost no response to the previous culling treatments. The relationship of net canopy photosynthesis to LAI was linear for the frequently defoliated swards and curvilinear for regrowing swards. The reasons for this difference were examined.     

Source : sink ratio and leaf senescence in maize:: II. Nitrogen metabolism during grain filling

Leaf senescence in a recent maize (Zea mays L.) hybrid is delayed relative to that in an older maize hybrid and the trait is associated with an improvement of the ratio of assimilate supply (i.e., source) and demand (i.e., sink) during grain filling. This study examined whether effects of source : sink ratio of leaf longevity in an old and more recent hybrid are associated with changes in leaf nitrogen (N) concentration and N uptake during grain filling. A 3-year field study was conducted with maize hybrids Pride 5 (old) and Pioneer 3902 (recent) grown at two soil-N levels: 150 kg⁻¹ N ha⁻¹ was broadcast in the high N treatment while none was added to the low N treatment. Four imposed source : sink treatments ranged from partial defoliation to no grain. Leaf N of the control treatments did not differ between the two hybrids, but the decline in leaf N from the control to the no-sink treatment was larger for Pioneer 3902 than for Pride 5. Total N uptake in above-ground portions was 10 and 18% greater in the new than in the old hybrid under low and high soil-N conditions, respectively. The difference in the total N uptake between the two hybrids could be attributed to post-silking N uptake. The proportion of N in the grain derived from post-silking N uptake was 60% for Pioneer 3902 and 40% for Pride 5 and this proportion was positively associated with the source : sink ratio. Higher rates of N uptake in Pioneer 3902 vs. Pride 5 appear to be, in part, the result of higher rates of dry matter accumulation of the newer hybrid during grain filling.     

Effect of foliar treatments to durum wheat on flag leaf senescence, grain yield, quality and deoxynivalenol contamination in North Italy

Since the production of durum wheat in the drier areas of the Mediterranean Basin is characterized by high variability in terms of yield and grain quality, there is also considerable interest in developing durum wheat in the northern regions, where the pedo-climatic conditions can offer the possibility of obtaining grain yields with higher technological quality and stability. However, the climatic conditions in the northern regions make durum wheat more prone to fungal foliar disease, particularly to Septoria Tritici Blotch (Septoria tritici Rob.) and to Fusarium Head Blight (Fusarium graminearum Petch and Fusarium culmorum Sacc.), with the consequent occurrence of DON in grains.Field experiments have been conducted over two growing seasons at four sites in North West Italy to evaluate the effect of fungicides and foliar nitrogen fertilizer application on durum wheat yield and grain quality. Five combinations of foliar application were compared at each site and each year (untreated control, azole fungicide application at heading, strobilurin fungicide at the stem elongation stage and/or at heading, the addition of a foliar N fertilizer to a fungicide programme). The following parameters were analysed: Septoria Tritici Blotch (STB) severity, flag leaf greenness using a chlorophyll meter, grain yield, test weight, grain protein content, ash content, vitreousness, Fusarium Head Blight (FHB) incidence and severity and deoxynivalenol (DON) contamination. The collected data underline that the cultivation of durum wheat at the climatic conditions of North Italy is actually risky and needs a direct control of fungal disease, which would be able to reduce the development of both foliar and head attacks. The double treatment, with a strobilurin application during the stem elongation stage and azole at heading, results to be an essential practice and showed advantages in terms of the delay of flag leaf senescence (+27%), STB control (+31), FHB control (+11%), yield (+32%) and DON contamination (−45%), compared to the untreated control. Other foliar treatments at heading, such as strobilurin or foliar N fertilizer applications, do not seem to provide any further advantage, for either grain yield or quality. No significant effect of fungicide or foliar N fertilizer application was recorded on the protein or ash concentration or vitreousness.     

鲜叶水份、环境温度与杀青

茶叶杀青中供需热量 ,会受到鲜叶水份含量和所处环境温度的影响。实践得知 ,水份含量高时 ,杀青时间会相应延长。在环境温度低的春季 ,杀青锅底部必须烧至微红 ;气温高的暑伏季节 ,锅温只需烧至呈灰白色即能满足工艺处理要求 (指加工普通绿茶的大锅 )。因此试验得出在常温 2 0℃下的最佳供需热系数 ,必须结合环境温度和鲜叶含水率的进行修正。但是水份含量与环境温度 ,到底会产生多大的影响 ?其调整幅度如何掌握 ,我们可以按照有关公式求得。1 .鲜叶水份含量的影响 :从茶叶比热计算的经验公式 C=0 .38+ 0 .62W可知 ,鲜叶含水率的多少 ,决定…     

Source : sink ratio and leaf senescence in maize:: I. Dry matter accumulation and partitioning during grain filling

Whether the stay-green characteristic of recent maize hybrids is related to a larger source : sink ratio and/or a more efficient use of N during reproductive development was studied in a 3-year field experiment. The experiment was conducted with two short-season maize hybrids, Pride 5 (old) and Pioneer 3902 (recent), grown at two soil-N levels and with source : sink treatments during grain filling ranging from partial defoliation to no grain. Results confirmed that greater dry matter accumulation of Pioneer 3902, relative to Pride 5, was associated with greater leaf longevity. Change in stover weight from silking to maturity an indicator of the difference in supply and demand of assimilates during grain filling, varied from −30% with defoliation to +25% for the no sink treatment. The change was always greater in the new hybrid, indicating that the old hybrid was more source limited. Number of green leaves, an indicator of leaf longevity, was greatest when supply and demand of assimilates during grain filling were approximately equal. Leaf longevity was enhanced by an increase in soil N and the effect was larger in the high source : sink treatments, but differences in leaf longevity between the two hybrids were not influenced by soil-N level. In conclusion, increased leaf longevity of a new relative to an old hybrid was associated with a larger source : sink ratio during grain filling.