排序方式： 共有23条查询结果，搜索用时 15 毫秒
11.
In this study, scanning electron microscopy (SEM) revealed the formation of pits and pores on the surfaces of starch granules in response to drought stress, with substantially more pronounced effects in the ordinary yield potential wheat cv. Xindong 23 than the excellent yield potential wheat cv. Xindong 20. Drought induced a significant reduction in starch granule sizes in both wheat varieties, though the reduction observed in Xindong 23 was six times more pronounced than that observed for Xindong 20. Amyloglucosidase and α-amylase treatment of starch from wheat grown in drought conditions released significantly more reducing sugars compared with samples from irrigated controls. SEM and confocal laser scanning microscopy (CLSM) revealed that starch granules from the two wheat varieties grown under drought conditions had substantially increased fluorescence after treatment with proteolytic enzymes and staining with methanolic merbromin and 3-(4-carboxybenzoyl) quinoline-2-carboxaldehyde dyes. Analysis of pasting properties showed significant increases of peak viscosity, trough viscosity, break down, and setback following drought stresses. Furthermore, drought induced a significant reduction in the water binding capacity and increased damage to starch only in Xindong 23. These results provide insight into the potential mechanisms through which drought influences the ultrastructures and physicochemical properties of starch in wheat. 相似文献
12.
应用双光子吸收法测定128只正常猫的骨矿物质 总被引：1，自引：0，他引：1
用钆－１５３双光子吸收法（ＤＰＡ）测定了１２８只正常猫（♂７２，♀５６）左右桡尺骨、肱骨、胫骨、股骨远端及第５或６腰椎等９个部位的骨矿物含量（ＢＭＣ）和骨密度（ＢＭＤ），确定了各骨骼ＢＭＣ和ＢＭＤ的正常值范围，找出了猫ＢＭＣ／ＢＭＤ与年龄、体重及性别的关系。结果显示，１～２岁公、母猫各部位的ＢＭＣ和ＢＭＤ随年龄增长而增加，以后则缓慢下降。各部位ＢＭＣ／ＢＭＤ与体重显著正相关，可根据体重计算其ＢＭＣ和ＢＭＤ值。母猫所有的ＢＭＣ和ＢＭＤ参数均低于公猫，其差异主要受体重的影响（公猫体重比母猫重）。 相似文献
13.
Pre-anthesis non-structural carbohydrate reserve in the stem enhances the sink strength of inferior spikelets during grain filling of rice 总被引：1，自引：0，他引：1
Jing FuZuanhua Huang Zhiqin WangJianchnag Yang Jianhua Zhang 《Field Crops Research》2011,123(2):170-182
Sink strength plays an important role in grain filling of cereals but how it is related to the pre-anthesis non-structural carbohydrate (NSC) reserves is not clear. This study investigated if and how an increase in NSC reserves could enhance sink strength, and consequently improve grain filling of later-flowering inferior spikelets (in contrast to the earlier flowering superior spikelets) for rice varieties with large panicles. Two “super” rice varieties (the recently bred high-yielding rice) and two New Plant Type (NPT, named in IRRI for the extra-large panicle) rice lines were compared with two elite inbred varieties under field-grown conditions. Three nitrogen (N) treatments, applied at the stages of panicle initiation, spikelet differentiation or both, were adopted with no N application during the mid-season as control. Both super rice and NPT rice showed a greater yield capacity as a result of a larger panicle than the elite inbred rice. However, a lower percentage of filled grains limited the realization of higher yield potential in super rice and especially in NPT rice, due to their lower grain filling rate and the smaller grain weight of their inferior spikelets. The low grain filling rate and small grain weight of inferior spikelets are mainly attributed to a poor sink strength as a result of small sink size (small number of endosperm cells) and low sink activity, e.g. low activities of sucrose synthase (SuSase) and adenosine diphosphoglucose pyrophosphorylase (AGPase). The amounts of NSC in the stem and NSC per spikelet at the heading time are significantly and positively correlated with sink strength (number of endosperm cells and activities of SuSase and AGPase), grain filling rate, and grain weight of inferior spikelets. Nitrogen application at the spikelet differentiation stage significantly increased, whereas N application at the panicle initiation or at both panicle initiation and spikelet differentiation stages, significantly reduced, NSC per spikelet at the heading time, sink strength, grain filling rate, and grain weight of inferior spikelets in super rice. The results suggest that pre-anthesis NSC reserves in the stem are closely associated with the sink strength during grain filling of rice, and N application at the spikelet differentiation stage would be a good practice to increase pre-anthesis NSC reserves, and consequently to enhance sink strength for rice varieties with large panicles, such as super rice varieties. 相似文献
14.
The occurrence of pre-maturity α-amylase (PMA) is a major cause of poor bread-making quality (low Hagberg Falling Number) in wheat grain. In susceptible genotypes, it involves the excessive accumulation of high isoelectric point (pI) α-amylase in mature grain prior to germination and in the absence of pre-harvest sprouting. Several factors regulate PMA formation in developing grain, including genotype, agronomy, and environmental conditions. In particular, a cold period during mid-grain development has been found to be a major stimulus for PMA induction. Although the factors affecting the PMA occurrence are well known, little is known about the molecular mechanism governing its induction. The plant hormones abscisic acid (ABA) and gibberellins (GAs) influence various aspects of grain development, and it has been suggested that PMA involves changes in the amount of these hormones or the sensitivity of the grain to these hormones. This review summarizes recent studies investigating the role of ABA and GAs in PMA induction and PMA occurrence. 相似文献
15.
不同量化RT-PCR的方法在棉花纤维GhCAD基因表达中的研究 总被引：2，自引：2，他引：0
以陆地棉（Gossypium hirsutum L.）高代品系CJ01在开花后5、10、15、20、25d（DPA）共5个不同发育时期的棉花纤维为材料,分别利用常规半定量RT-PCR法、QuantumRNA™18S内标相对定量法以及实时荧光定量 RT-PCR法,对棉花肉桂醇脱氢酶（GhCAD）基因在棉花纤维不同发育时期中的表达进行相对定量分析,并测定了内标表达的稳定性。结果表明3种方法获得相似的结果,GhCAD基因在5～15DPA时表达量较低,20、25 DPA时表达量升高。3种方法虽各有利弊,但均为研究基因量化表达的有力工具。 相似文献
16.
用钆－１５３双光子吸收法（ＤＰＡ）测定１２１只健康大、小型犬（其中大型犬７８只,小型犬４３只）的骨矿含量（ＢＭＣ）和骨密度（ＢＭＤ）。每只犬测量左右桡尺骨、肱骨、胫骨、股骨远端、腰椎（Ｌ－５或Ｌ－６,仅小型犬）、尾椎（Ｃ－７或Ｃ－８,仅大型犬）等１０个部位。结果表明,小型犬各部位骨量显著少于大型犬,两体型母犬骨量均比公犬低。经直线回归和多元回归分析,大、小型犬各部位骨量随年龄增长而下降,其中大型犬四肢骨量下降尤为明显。所有犬各部位骨量与体重呈显著正相关,小型犬每公斤体重的骨量增长率高于大型犬,两体型母犬骨量增长均低于公犬。结论：年龄、体重、体型和性别均是影响犬骨量的因素,其中体重和体型是主要因素,年龄对骨量亦产生一定作用。 相似文献
17.
Hydrogen peroxide (H2O2) is one of the important by-products produced by plant and fruit tissues during normal metabolism as well as under stress conditions. Evidence suggests that it is actively involved in many physiological activities in plants, including ripening, senescence and the development of disorders. Quantitative measurement of H2O2 in fruit has been a challenge due to variations in methodologies, and their sensitivities and interferences present in plant samples. Among the currently used methodologies, chemiluminescence (CL) is one of the most promising, due to its high specificity and sensitivity. However, direct application of CL methods developed for leaf analysis is not suitable for fruit, especially fruit peel tissues, possibly due to interfering compounds in fruit tissues. In this study, evaluation of the efficiency of removal of interfering compounds by PVP, PVPP and activated charcoal revealed that the PVPP is the most effective compound to remove the interference. This modified protocol can measure H2O2 content in apple peel and flesh tissues. ‘Red Delicious’ apple peel and flesh tissues were measured with amount of 1.48 and 1.03 μmol/g FW, respectively. The established protocol can also be used for a wide variety of tissues in addition to apple fruit, including strawberry tissues (fruit, calyx and leaves) and spinach leaves. This protocol was applied to determine the H2O2 concentration in 1-MCP and DPA treated apples after 5 months of storage, but no significant difference in H2O2 in those samples was found. Direct comparison of CL with a commercial hydrogen peroxide measurement OXIS kit was also made. The challenges to accurately assay H2O2 in fruit/plant tissue were discussed. 相似文献
18.
19.
20.
青椒的冷害及防治技术研究 总被引：1，自引：0，他引：1
试验对不同低温贮藏条件下青椒果实的呼吸强度、丙二醛含量的变化和冷害发生规律以及防治技术进行了研究。结果表明,在低温胁迫下,青椒果实呼吸异常升高,丙二醛含量积累峰提前出现。与0℃贮藏条件相比,3℃下贮藏的青椒其冷害发生更早,程度更严重。单果套袋和DPA处理可将青椒在0℃下的贮藏期延长到45d。 相似文献