Evaluation of Root Sink Ability of Sweet Potato (Ipomoea batatas Lam.) Cultivars on the Basis of Enzymatic Activity in the Starch Synthesis Pathway

Activities of five enzymes, sucrose synthase (SUS), uridine 5'-diphosphate glucose pyrophosphorylase (UDPGPPase), fructose-1,6 bisphosphatase (FBPase), adenosine 5'diphosphate glucose pyrophosphorylase (ADPGPPase) and starch synthase (STS), in the metabolic pathway of starch synthesis, were compared between two sweet potato ( Ipomoea batatas Lam.) cultivars, Koganesengan (C.V.KOG, a recently released high yield cultivar) and Tsurunasigenji (C.V.TSU, an old, local cultivar with poor yield). The measurements were carried out using the root samples (tuberous, thick and fibrous roots) harvested at the fast tubering stage. Of the five enzymes, SUS, ADPGPPase and STS showed high activities in the tuberous root, particularly in that of C.V.KOG, and a similar trend was observed for activities of these enzymes on a protein basis. The increased activity of the three enzymes is considered to be one of the characteristics in a high yield cultivar, allowing the root to function effectively as a starch synthesis and storage organ.     

猴头菌营养生长最佳条件研究

对4个猴头菌菌株的研究表明,猴头菌营养生长阶段最佳碳源为淀粉,最佳氮源为麦麸及蛋白胨,最适碳氮比为20∶1,最适pH为4.0～5.0,最适温度为25～29℃。     

不同施肥条件对鱼腥草碳氮代谢生理指标的影响

【研究目的】结合前期对产量、品质的研究，探讨不同施肥条件下鱼腥草叶片主要碳氮代谢指标的变化及其与产量形成的关系。【方法】采用单因子随机区组设计进行施肥实验，测定鱼腥草叶片光合速率、硝酸还原酶活性、叶绿素和粗蛋白的含量。【结果】各施肥处理中以较低施肥水平人粪尿处理的鱼腥草叶片含叶绿素总量最高，达2.552 mg/gFW，以中等施肥水平鸭粪的净光合速率最高，为8.306μmol/(m2·s)。施用不同肥料的鱼腥草叶片硝酸还原酶活性大小为：鸭粪>猪粪>常规施肥>化肥>人粪尿，各处理以中等施肥水平的猪粪处理的硝酸还原酶最高，达46.2μg NO2-/(h·g)FW；粗蛋白以施用较高水平化肥的最高（13.31%）。【结论】施用有机肥能显著提高鱼腥草叶片的碳代谢，这有利于其产量的形成；但施用人粪尿不利于提高鱼腥草叶片硝酸还原酶活性和蛋白质的形成与积累。     

不同基因型抗虫棉的光合生产与叶源特征

以33B为对照,对早发型常规Bt棉鲁棉研17、鲁棉研21,晚发型Bt棉鲁棉研22,杂交Bt棉鲁棉研15、鲁棉研20进行了2年的种植和比较。早发型品种中前期干物质积累和叶面积增长快,但后期干物质积累慢、叶面积下降快,表现出明显的早发早熟和干旱年份易早衰的特点;晚发型品种前期干物质积累和叶面积增长慢,但后期增长快,表现出明显的晚发甚至贪青晚熟的特点。两个杂交棉品种表现出与早发型品种基本相同的生育规律,但中前期叶面积系数和干物质积累量显著高于其它供试品种。盛铃期以前,未见品种间功能叶光合速率的显著差异,但在干旱年份,早发型品种在始絮期功能叶的光合速率显著低于晚发型品种。早发型品种中后期的根冠比和功能叶含K量显著低于晚发型品种,而叶面积载荷量却显著高于晚发型品种。不同品种干物质产量和熟相的差异可能分别与叶面积系数大小和库源比例不同有关。     

Associations between grain yield and carbon isotope discrimination in cowpea

Twenty cowpea (Vigna unguiculata L. Walp.) genotypes, comprising Kenyan cultivars and Kenyan and introduced breedings lines, were grown in 15 replicated field trials carried out at three locations in semi-arid eastern Kenya over four seasons. Grain and straw yields and the carbon isotope discrimination (Δ) of this material were determined, and days to flowering and maturity observed.None of the seasons in which the trials were conducted was appreciably drier than the long term average for the sites, and some trials received excessive rain. Averaging the data for the 15 trials, one genotype yielded much less grain (77 g m⁻²) than the 19 others, whose yield ranged from 125 to 177 g m⁻² (average 148 g m⁻²). Trial mean yield trials had a high straw Δ (r = +0.567) and had received more rain between flowering and maturity (r = +0.428) than lower yielding ones. Among genotypes, averaging over trials, the correlation coefficient (r) between grain yield and grain Δ was +0.394, and between grain yield and straw Δ, +0.460. Early genotypes had the highest grain Δ and straw Δ. The correlation among genotypes between date of flowering and grain Δ was −0.632 and with straw Δ, −0.502. When comparisons were made among trials, there was no clear relationship between the strength of the correlations among genotypes between grain yield and straw Δ or grain Δ and the degree of stress experienced by a trial (as indicated by the rainfall it had received). It appeared that this was because the variances of grain Δ and straw Δ were greater in the most droughted trials, whereas the variance of yield was greatest in the least droughted trials.It is concluded that the genetic correlation between grain yield and either grain Δ or straw Δ is unlikely to be strong enough to make either Δ a useful surrogate or adjunct in selecting for high yield in the segregating generations of a breeding programme for semi-arid eastern Kenya, but that Δ may be of value in the selection of parent genotypes.     

A high temperature/low oxygen pulse improves cold storage disinfestation

Short periods of elevated temperature under controlled atmospheres (CA) effectively control insect pests. Cold treatment is also an effective non-chemical disinfestation process. If synergistic effects can be found by combining treatments, these may provide opportunities for cost reduction. Tests were performed to evaluate the tolerance of Packham's Triumph pears (Pyrus communis L.) to a range of temperatures (30–40 °C) combined with low oxygen (O₂ < 1 kPa). Treatment duration was 16–48 h and was followed by 1 month storage at 0 °C under air. When held at 30 °C, pears withstood up to 30 h of hypoxia. After cold storage, pears ripened slightly faster than controls but were undamaged. A temperature of 35 °C induced slight skin browning, and 40 °C resulted in substantial skin blackening. Some treatments were also tested on survival of lightbrown apple moth (LBAM), Epiphyas postvittana (Walker). All developmental stages were subjected to either 16 h at 30 °C, or 16 h under hypoxia, or 1 month at 0 °C, or a combination of the three treatments. With all treatments combined, all eggs, larvae and adults were killed. Only 4% of the pupae produced adults and combined treatments led to an increase in pupa mortality of 38%. A combined treatment (tolerated by pears) consisting of 30 h at 30 °C under low O₂ plus 1 month cold storage under air, killed 100% of LBAM pupae, and 100% of 5th instar larvae of both codling moth, Cydia pomonella (L.), and oriental fruit moth, Grapholita molesta (Busck). Implementation of such treatments would not require substantial investments for fruit industries equipped with CA storage facilities.     

减少蔬菜碳足迹的主要肥料合理用量分析——以浏阳蔬菜生产合作社为例

肥料是影响作物产量和农业碳排放的主要因子之一。研究基于减少单位产量碳足迹,探讨主要肥料的合理用量。对浏阳4个合作社中黄瓜、苦瓜、豆角、莴笋、苋菜、茄子等8种蔬菜生产进行3年定点调查,并对相关数据进行统计分析。结果表明:每季蔬菜生产氮肥、磷肥、钾肥、厩肥施用量依次为:0、327.2、0、48936 kg/hm2,可使单位产量碳足迹减少85.85%,产量提高24.11%。因此,浏阳发展高效低碳蔬菜种植产业关键施肥技术在于减少氮肥与钾肥的使用,控制磷肥的用量,增施厩肥。     

初花期源库比变化对棉花下部"铃-叶系统"生理特征的影响

对棉花初花期进行去叶和去蕾处理,研究改变棉花源库比对早期"铃-叶"系统生理状态的影响.结果表明,源库比改变明显地影响着棉叶和棉铃中蛋白质、可溶性糖和淀粉的含量,但蛋白质、可溶性糖、淀粉的含量对源库比变化的反应程度不同.减库处理可以提高叶片中蛋白质、可溶性糖和淀粉的含量,促进子棉中碳水化合物的积累,提高单铃重,并促进后期果枝叶中叶绿素的合成,延长叶片功能期,但是不利于棉子中蛋白质的合成;减源处理促进前期果枝叶中叶绿素含量,但是使后期果枝叶中叶绿素含量快速下降,表现出早衰迹象;并且减源处理不利于叶片中蛋白质的合成.     

Grain weight responses to post-anthesis spikelet-trimming in an old and a modern wheat under Mediterranean conditions

Average grain weight is a major yield component contributing to its variation, especially in Mediterranean regions where grain weight is frequently exposed to terminal stresses affecting grain growth. Most of the literature agrees that wheat grain growth is hardly limited by the source. However, no source–sink ratios studies seem to have been conducted in the Mediterranean region to determine to what degree wheat grain growth is actually limited by the source in these particular regions. We conducted two field experiments in Catalonia (north-eastern Spain), where an old cultivar (Anza) and a more recently released one (Soissons) were sown in a range of different nitrogen and water availabilities and sowing dates. This was to analyse the degree of source limitation for grain growth. Sink size was modified by removing half of the spikelets c. 10 days after anthesis, virtually doubling the availability of assimilates per grain effectively growing.

Trimming the spikes did not produce significant changes in grain growth rate or duration of grain filling. Consequently, grain weight did not respond noticeably to the reduction in sink demand and any eventual response has been far from representing a strong competition among grains during grain filling.     

旱种水稻结实期茎中碳同化物的运转及其生理机制

以杂交水稻汕优63和籼稻扬稻6号为材料，研究了旱种(地膜覆盖栽培)水稻结实期茎中碳同化物的运转及其生理机制。结果表明，抽穗至成熟期旱种水稻标记14C从茎中向籽粒的再分配、茎中非结构性碳水化合物(NSC)的运转率及其对籽粒的贡献率均显著高于水种(常规栽培)水稻。水稻旱种后籽粒中的蔗糖合成酶和酸性转化酶活性、茎中α-淀