A new sunflower high oleic mutation confers stable oil grain fatty acid composition across environments

The oil industry demands sunflower oils with high oleic acid content. New varieties producing high oleic oils independently of the growing environment are needed as growers could receive an extra prime for offering them. Oil fatty acid composition of high oleic sunflower hybrids currently available carrying the Pervenets mutation could however be affected by the temperature during the grain filling period. A new high oleic mutation has been obtained to attain oils with ultra-high oleic levels (>90%oleic acid content). This new structural mutation would be able to reduce the variation in oleic acid percentage to changes in the minimum night temperature (MNT). The aim of this work was to assess the response of oil fatty acid composition of the new high oleic mutation to MNT compared to traditional and Pervenets genotypes. Field experiments in different sowing dates and locations and one growth chambers experiment were performed to explore a wide range of temperatures (11.8–23.2 °C) during grain filling. The oleic acid percentage in traditional and high oleic Pervenets genotypes varied between 15.0–50.9% and 87.4–91.2%, respectively, while the new mutation genotype presented values of oleic acid between 91.3 and 92.5%. Moreover, the oleic acid percentage of traditional and Pervenets genotypes showed a linear and positive response to temperature (slopes 2.95 and 0.28%oleic acid °C⁻¹, respectively). No response to temperature was detected in the new mutation genotype. The ultra-high oleic quality from the new high oleic sunflower mutant could be obtained in a wide range of environments as the fatty acid composition was not affected by temperature during grain filling, representing an advantage over the high oleic Pervenets and traditional genotypes.     

Contribution of incident solar radiation on leaves and pods to soybean seed weight and composition

The weight and composition of soybean seeds (Glycine Max L. Merrill) depend on changes in carbon and nitrogen assimilate supply during grain filling. Soybean pods and seeds are green, evidencing their capacity to capture light. However, the current physiological knowledge does not consider any effect of incident solar radiation reaching the pods on seed weight and composition. The objective of this work was to investigate the response of seed weight and composition to changes in assimilate supply from leaves, to the incident solar radiation reaching the pods and to the combination of both, changes in assimilate supply from the leaves and incident solar radiation on pods of soybean plants. Field experiments were performed during two growing seasons at Balcarce, Argentina. Treatments modified the amount of assimilates supplied by the leaves (plant shading, defoliation), the solar radiation reaching the pods (pod shading) or both (defoliation and pod shading) during seed filling. Plant shading and defoliation reduced seed weight, oil concentration and oil and protein content and increased the concentration of saturated and poli-unsaturated fatty acids while reduced oleic acid percentage. Pod shading increased the concentration of stearic acid and reduced the concentration of linolenic acid. When pods were shaded on defoliated plants, seed weight and oil and protein content decreased while fatty acid composition was similar to values obtained under defoliation treatment. Based on these results, a conceptual model that considers photoheterotrophic nature of reproductive structures of soybean is proposed. Seed weight, oil and protein content and oil fatty acid composition depended on assimilate availability for the seeds. The response of oil and protein content to assimilate supply depended on whether leaves were present or not. The effect of solar radiation incident on pods depended on the amount of assimilates available for the seeds: (i) when carbon allocated was low (defoliation treatments), pods contributed to seed carbon economy but solar radiation incident on them did not affect fatty acid composition; (ii) when carbon allocated to the seeds was high (intact plants), contribution of pods to seed carbon economy was not significant, but the amount of solar radiation incident on pods produced significant changes in fatty acid composition.     

The accumulation pattern in developing seeds and its relation to fatty acid variation in soybean

Sixty soybean cultivars from Japan and the USA formed five maturity groups (IIb‐Vc) based on number of days from sowing to flowering and number of days from flowering to maturity. Highly significant intervarietal differences in fatty acid composition were found in all the maturity groups, especially in IIc. Stearic and oleic acids showed a larger variation than palmitic, linoleic and linolenic acids. Principal component analysis suggested that the total variation of fatty acid composition depended mainly on the desaturation levels from oleic to linoleic acid. Three cultivars exhibiting unique fatty acid composition, together with a standard cultivar, were examined for the contents of the five fatty acids, as well as crude oil at eight seed‐filling stages. For all four cultivars, it was found that crude oil content increased sigmoidally with advancing filling stage, and that the accumulation patterns of palmitic, linoleic and linolenic acids were similar to that of crude oil. However, the accumulation pattern of stearic acid was different from that of crude oil and divided the cultivars into two distinct groups. For oleic acid, only the cultivar ‘Aburamame’ showed a rapid increase in proportion with advancing filling stage, although not differing markedly in accumulated content from the other cultivars. These results indicate that analysing the accumulation patterns of fatty acids could explain the latent genetic variation in fatty acid composition of soybean seeds.     

Genetic variability of tocopherol composition in sunflower seeds as a basis of breeding for improved oil quality

The variability of seed tocopherol content in wild sunflower species, the expressivity of tph1 and tph2 mutations in different lines and the oxidative stability of sunflower oil with altered tocopherol and fatty acid composition were objectives of this research. Near-isogenic lines for three genes, i.e. Tph1, Tph2, and Ol, were developed and investigated. Tocopherol content was determined with TLC and HPLC, as well as fatty acid composition with GC of methyl esters. Rancimat tests were used to estimate the oxidative stability of the oil. The seed tocopherol composition of wild sunflower species was shown to be uniform with a prevailing content of the α-homologue (90-99%). The genetic background of different near-isogenic lines was found to influence expressivity of mutations for tocopherol composition. High content of strong antioxidants, such as β-, γ-, and δ-tocopherols increased oil oxidative stability of linoleic and oleic types of oil by 1.2–3.0 times. The breeding model of sunflower hybrids should include antioxidant and vitamin parameters balanced for oils of different applications.     

Response of Some Quality Traits of Sunflower Seeds and Oil to Different Environments

Five sunflower hybrids and one open-pollinated variety were sown at two locations in West Germany and at two-sowings at Giza, Egypt (summer and winter seasons). Cultivars showed different response concerning oil and protein contents as well as fatty acid composition. Highest protein content was observed from Giza in winter season. Cultivars differed significantly with this respect under different environments. However, oil content was not significantly affected by environments X cultivars interaction.
Regarding fatty acid composition, palmitic and stearic acids were insignificantly affected. However, highest oleic acid percentage (57.5%) was observed at Giza in summer sowing by Nhy , hybrid, while at Giza in winter sowing the highest value (25.7%) was produced by Semu 209 hybrid. The differences between the two Germany locations were relatively low in range from 14.6–17.6%. Concerning linoleic acid, it showed an opposite trend.
Environments X cultivars interaction showed significant influence on total tocopherol content.     

Influence of leaf and silique photosynthesis on seeds yield and seeds oil quality of oilseed rape (Brassica napus L.)

With the purpose of enhancing oil production, the present work was carried out to elucidate relationships between photosynthesis of leaves, siliques and seeds yield and seeds oil accumulation of oilseed rape. Field trials, in which two repeated experiments was carried out during 2012–2014 growth season, a rape hybrids the “Qin You No.7” (Brassica napus L.) variety was taken into account. The results showed that, on rape plant the photosynthetic capacity and chlorophyll a, b, carotenoid contents of leaf were significantly higher than that of silique shell. Oil content of 94.7% was achieved in young seeds (sampled at 25th day after flowering ending stage of the tested rape plant) versus to mature seeds, saturated fatty acids percent was higher whereas oleic acid percent was lower of oil extracted from young seeds. During flowering period of the rape plants tested, area and dry weight of leaves attained maximum, treatments of removing leaves induced reduction in seeds number per silique, siliques number, seeds yield per plant and seeds oil content, these indexes were respectively decreased by 73.6%, 43.4%, 83.4% and 10.5% in maximum, and seeds oil composition was not significantly influenced; during seeds growing period of the tested plants, surface area and dry weight of siliques attained maximum, under shading siliques treatment, the 1000-seed weight, seeds yield per plant and seeds oil content were respectively reduced by 57.5%, 61.4% and 44.7% in maximum, and seeds oil oleic acid (C18:1) and linolenic acid (C18:3) percent was decreased, linolic acid (C18:2) and erucidic acid (C22:1) percent was increased. So for oilseed rape plant during flowering period, surface area and photosynthesis of leaves dramatically influenced siliques number, seeds number and seeds yield; while in seeds growth period, surface area and photosynthesis of siliques greatly influenced 1000-seed yield, seeds yield, seeds oil content and oil composition; oil accumulation in rape seeds initiated early since seeds commencing growth, seed mature degree influenced oil composition of seeds.     

Contrasting patterns of fatty acid composition and oil accumulation during fruit growth in several olive varieties and locations in a non-Mediterranean region

Olive growing has expanded considerably in the last few decades outside of the Mediterranean Basin to non-traditional regions in the Southern Hemisphere. When growing olive genotypes (i.e., varieties) outside of their area of origin, the importance of environmental factors such as temperature and genotype × environment interactions in determining olive oil production and oil quality has been suggested. In several Mediterranean varieties and one South American variety, we assessed the dynamics of fruit growth and oil accumulation along with the evolution of fatty acid composition at multiple locations over two growing seasons. Oleic acid content (%), the principal fatty acid present in olive oil, showed four contrasting patterns during fruit growth when modeled against thermal time from flowering using linear and bilinear regressions: (1) a sharp linear decrease for the varieties ‘Arauco’ and ‘Arbequina’; (2) a plateau followed by a late linear decrease of moderate slope for ‘Barnea’ and ‘Manzanilla Fina’; (3) a slow linear decrease for ‘Frantoio’; and (4) no decrease in ‘Coratina’. Linoleic acid (%) showed linear increases in ‘Arauco’ and ‘Arbequina’ that appear to be inversely related to the decreases in oleic acid, while bilinear patterns were found for many other varieties. Both the rates of fruit growth and of oil accumulation were more important in determining maximum fruit dry weight and oil concentration (%), respectively, than duration when expressed on a thermal time basis. Temperature during oil synthesis was negatively related to final oil concentration. Experiments under controlled conditions would greatly contribute to our understanding of how fruit growth as well as oil quantity and quality are influenced by environmental factors.     

Irrigation has Little Effect on Unsaturated Fatty Acid Content in Soya Bean Seed Oil within Genotypes Differing in Fatty Acid Profile

Soya bean [ Glycine max (L.) Merr.] genotypes with modified unsaturated fatty acid profiles in seed oil have been developed. Higher oleic (18:1) and lower linolenic (18:3) acids are desirable for increased use of soya bean oil in food and industrial applications. The environment affects levels of unsaturated fatty acids in soya bean and it is important that desired components of seed oil are produced across a range of growing conditions. Our objective was to determine whether irrigation affects fatty acid levels in soya bean with altered fatty acid profiles. Seven modified oil genotypes which included elevated oleic acids, and/or reduced linolenic acid, along with two common soya bean varieties were evaluated with and without irrigation (rain fed) in four environments in each of 2 years. Irrigation generally had no significant influence on unsaturated fatty acid accumulation in seed oil in soya bean genotypes with altered fatty acid profiles. However, irrigation tended to show desirable effects on 18:1 and 18:3 contents in the genotypes studied. Oleic acid tended to be higher in eight of the nine genotypes and linolenic acid was lower in six of the nine genotypes under irrigation vs. rain fed treatments.     

Dynamics of Dry Matter Accumulation in the Developing Grains of Three Wheat Genotypes with Contrasting Grain Weight

The accumulation of dry matter and its major components was studied in developing grains of two bold seeded (Selection-111 and IWP-5308) and one small seeded (kalyansona) wheat genotypes grown in pot culture condition. It was observed that in kalyansona, a sharp reduction in grain water content during the critical stage of grain enlargement limits its size resulting in compact filling of grains. In the developing grains of Selection-111 and IWP-5308, the high rate of dry matter accumulation was associated with their larger grain sink size. However, their lower grain density compared to kalyansona could be explained on the basis of non-complementation between synthetic component and grain size (structural component). This non-complementation may be due to relatively higher thermosensitive synthetic mechanism in the bold seeded genotypes.     

起垄栽培对不同基因型冬小麦生理特性及子粒蛋白质含量的影响

以3个不同基因型冬小麦品种为材料，研究了起垄栽培对冬小麦生理特性及子粒蛋白质含量的影响，结果表明，起垄栽培可以提高灌浆初期小麦旗叶及子粒中游离氨基酸含量，提高灌浆后期旗叶硝酸还原酶活性和子粒蛋白质含量，但不同基因型品种之间存在差异。起垄栽培可以显著提高藁麦8901和郑麦975子粒蛋白质含量，而对弱筋品种豫麦50号影响不显著。     

植物生长营养液对燕麦生长和产量的影响

为明确植物生长营养液对燕麦生长及产量的影响,研究了燕麦拔节期、抽穗期和灌浆期喷施相同量不同稀释倍数的植物营养液后燕麦株高、干物质积累量、产量及产量构成因素的变化。结果表明:不同稀释倍数的营养液均可以缩短燕麦生育期,其中500倍稀释液与对照相比可提前7d成熟;各营养液处理的燕麦株高、干物质积累量和叶面积在抽穗期、灌浆期和成熟期均高于对照,各指标均随着稀释倍数的增加先升高后降低;喷施植物营养液后燕麦穗数、穗粒数、千粒重和产量均增加,喷施500倍稀释液后,燕麦穗数、生物产量和子粒产量与其他处理间差异均达显著水平,子粒增产达15.9%。     

Accumulation of Biomass and Nitrogen During Plant Growth in Highly Diverging Genotypes of Winter Wheat

Data are presented on the accumulation of nitrogen and total biomass into wheat plants at different stages in their ontogeny. Five genotypes of highly diverging origin and with widely deviating grain protein contents were cultivated at different nitrogen regimes (ranging between 0 and 150 kg N ha^-1). Growth curves as polynomials were calculated from representative subsamples of plant material collected from each plot at weekly intervals, commencing early in the vegetative stage and ending at complete maturity. Dry weights and nitrogen contents were determined for above-ground plant parts and for grains, when present, and were expressed per nr ground area. During the first 2 years total green areas were estimated as well and leaf area indices (LAIs) calculated and fitted to polynomials. The results from these trials revealed that the two American high-protein genotypes Goertzen 5559 and Frontiersman produced distinctly less biomass (mainly carbohydrates) than the Swedish genotypes Folke, Solid, and Lantvete during the later phases of growth. The lower biomass production of the American types after anthesis appeared to be more due to a decreased photosynthetic activity and less to a decrease in green area. It was also found that the American genotypes had a higher efficiency in remobilizing previously produced and stored assimilates than the modern Swedish cultivars Folke and Solid, which were more dependent on current photosynthesis. With respect to uptake of nitrogen into biomass there was very little variation between the genotypes at the early stages of plant life, but later on clear differences developed between the American and Swedish genotypes. Thus the former accumulated considerably less nitrogen than the latter, but since the differences between the two groups were still more pronounced regarding accumulation of biomass the American types exhibited higher concentrations of nitrogen in total biomass towards the end of the growing season. This higher concentration of N seems to indicate an increased relative ability for the American types to take up nitrogen from the soil during the grain filling phase but it is uncertain whether a causal relationship actually exists with the ability to accumulate protein in the grains. Estimates of the efficiency to redistribute nitrogen to the grain did not show any significant differences between the five genotypes and the most probable explanation for the high grain protein values of the American genotypes therefore seems to be their relatively low production of carbohydrates (and biomass). In a subsequent paper results horn a comprehensive field trial concerning grain and straw yields, structural yield components, soil analyses, etc. will be presented which further corroborate these conclusions.     

穗分化期外施24-表油菜素内酯(EBR)促进水稻源、库及籽粒灌浆的生理机制

水稻产量高低与其籽粒灌浆能力的强弱密切相关, 而籽粒灌浆能力的强弱受源和库的影响。已有研究表明, 油菜素甾醇类化合物(brassinosteroids, BRs)对水稻生长发育和产量具有正向调节作用。为进一步阐明BRs调控水稻源强、库容和库活性的生理机制及其相互关系, 本研究在大田条件下, 以粳稻日本晴为试验材料, 在穗分化期喷施24-表油菜素内酯(24-epibrassinolid, EBR), 分析其相关影响。首先, 两种不同浓度的EBR处理通过促进光合产物的合成及其在灌浆过程中的转运提高了水稻的源强。其次, 两种浓度EBR处理均增大了水稻的库容, 但两种处理的影响方式存在差异, 低浓度处理(T1) 显著提高水稻籽粒的千粒重, 对穗粒数的影响较小; 高浓度处理(T2)则显著增加单位面积的穗数和穗粒数, 对千粒重的影响较小。再次, 两处理同时提高了水稻强、弱势粒的蔗糖裂解酶活性, 尤其对弱势粒酸性转化酶(acid invertase, AI)活性的影响较大, 有助于光合产物向弱势粒分配, 进而促进弱势粒淀粉合成和籽粒灌浆, 提高其充实度和结实率。最后, 两处理均显著增加了水稻的产量, T1和T2分别平均增加5.6%和15.2%, T2比T1平均增产9.1%。因此, 与低浓度EBR处理下的千粒重增大相比, 高浓度处理下穗粒数的增加对产量影响更大。综上所述, 穗分化期进行EBR处理能够增大水稻的源强、库容和库活性, 进而促进光合物质的积累和分配, 有利于籽粒灌浆; 在光合物质供应充足和库活性显著提高的基础上, 库容的增大有助于产量的明显提高。     

大穗型小麦品种强、弱势籽粒淀粉积累和相关酶活性的比较

在大田条件下, 以两个大穗型小麦品种山农12和PH01-35为材料, 对籽粒发育过程中强、弱势籽粒淀粉积累及其相关酶活性变化进行了比较研究。结果表明, 两品种强势粒直链淀粉积累量和支链淀粉积累量均高于弱势粒。Logistic方程模拟淀粉积累过程, 强势粒淀粉积累起始势(C₀)高, 活跃持续期长, 平均积累速率(R_mean)高, 最终淀粉积累量高。 籽粒蔗糖合酶(SS)、ADPG焦磷酸化酶(AGPase)、UDPG焦磷酸化酶(UGPase)、可溶性淀粉合酶(SSS)和束缚态淀粉合酶(GBSS)活性均呈单峰曲线变化, 强势粒上述酶活性均高于弱势粒。花后7~21 d, 弱势粒蔗糖含量明显高于强势粒, 表明弱势粒淀粉积累量低, 并不以其淀粉合成底物的供给为限制因子, 而主要与淀粉合成能力低有关, 同时与籽粒灌浆前期胚乳细胞的数量关系密切。     

不同小麦品种粒重和蛋白质含量的穗粒位效应分析

小麦籽粒的发育存在时空差异,不同穗粒位的粒重和蛋白质产量也存在差异,剖析粒重和籽粒蛋白质含量的穗粒位效应,有助于深入了解小麦产量和品质的形成机制。于2009—2010和2010—2011小麦生长季进行大田试验,选用3种类型4个品种,分析了不同穗粒位的粒重、蛋白质积累和蛋白质含量的动态变化。结果表明,粒重和蛋白质积累量的穗粒位间变异大于年份(环境)间变异和基因型间变异;蛋白质含量的年份间变异大于基因型间变异和穗粒位间变异,而成熟期穗粒位间变异最大。大粒品种易受环境影响,小粒品种比较稳定。优质面包小麦品种开花后各时期的籽粒蛋白质含量普遍高于中筋小麦,但不同时期、不同年份差异较大。开花后各时期,强势粒的粒重、蛋白质积累量和蛋白质含量显著大于弱势粒,中部籽粒显著大于上部和下部籽粒;随着灌浆进程穗中部与下部籽粒的差异变小,至开花后36 d时,中部和下部籽粒的蛋白质含量无显著差异。随籽粒灌浆进程,不同品种各穗粒位的粒重和蛋白质积累均呈"慢–快–慢"的"S"型曲线变化,蛋白质含量均呈"高–低–高"的"V"型曲线变化,灌浆后期,中部和下部强势粒以及下部弱势粒的蛋白质含量增长速度明显快于其他穗粒位籽粒。粒重最大生长速率出现在开花后18~21 d,快速增重时期为开花后12~26 d;籽粒蛋白质最大积累速率出现在开花后21~24 d,快速积累时期为开花后13~32 d。根据本研究结果,我们认为高产优质小麦品种的特征是籽粒不宜过大,小花位粒数不宜过多,且中、下部籽粒较多,开花后13~26 d灌浆速率快。     

不同穗型超级稻品种籽粒灌浆特性

为探明不同穗粒型超级稻产量构成特点、籽粒灌浆特性及其与后期生理指标的关系。以不同生育期品种准两优527、两优培九、Y两优1号、玉香油占、黄花占为试验材料,在大田栽培条件下分期播种以确保不同生育期品种在相似的温光条件下灌浆结实。结果表明,不同播期平均产量及其构成因子的品种间差异显著,以两优培九产量最高(9.47 t hm^-2),玉香油占产量最低(8.39 t hm^-2)。依据每穗粒数和千粒重系统聚类分析,可将品种分为大粒型(准两优527)、中粒型(两优培九、Y两优1号)和小粒型(玉香油占、黄花占)。籽粒灌浆强度及持续时间的品种间差异明显。其中,大粒型品种籽粒灌浆起步快、强度大、峰值持续时间短,上、中、下部枝梗籽粒均为一段式灌浆;中粒型品种籽粒灌浆起步快、强度较小、峰值持续时间长,其上部枝梗籽粒为一段式灌浆,中、下部枝梗籽粒为两段式灌浆,高峰值分别在抽穗后12~18 d和24~30 d;小粒型品种籽粒灌浆起步慢、强度小、峰值持续时间长,其上、中部枝梗籽粒为一段式灌浆,下部枝梗籽粒为两段式灌浆。平均籽粒灌浆速率与品种的穗粒类型密切相关,其中,大粒型品种为0.68 mg d^-1,中粒型品种为0.48~0.51 mg d^-1,小粒型品种为0.41~0.47 mg d^-1。籽粒灌浆强度及持续时间与后期剑叶、根系生理指标有关,籽粒灌浆启动后,叶绿素含量、叶绿素a/b值、类胡萝卜素含量逐渐降低,剑叶可溶性糖含量、MDA含量逐渐上升,POD活性、CAT活性及根系活力先后出现2次升降过程。可见,不同穗粒型超级稻品种产量构成及籽粒灌浆特点的差异明显,籽粒灌浆强度及持续时间与品种的穗粒型及枝梗着生的部位有关,也与后期剑叶及根系衰老生理指标的变化趋势一致。     

不同氮收获指数水稻基因型的氮代谢特征

采用土培盆栽试验,以3个氮收获指数(NHI)有显著差异的水稻基因型4434(低NHI)、滇瑞302(中NHI)和余赤23(高NHI)为材料,研究了灌浆期叶片、穗颈和籽粒的氮代谢特点及与NHI的关系。结果表明,各基因型的籽粒产量、收获指数和籽粒氮积累量与NHI的变化一致,均以余赤231最大。花后植株氮素转运量表现为4434<滇瑞302<余赤231,基因型间差异极显著,而氮素转运率和转运氮的贡献率差异较小。成熟期水稻茎叶和籽粒的全氮含量、蛋白氮和非蛋白氮含量均表现为4434<滇瑞302<余赤231,全氮含量和蛋白氮含量存在显著差异,而非蛋白氮无显著差异;余赤231茎叶蛋白氮积累量显著低于4434和滇瑞302,而籽粒蛋白氮积累量显著升高,是高NHI水稻氮积累的主要特征。余赤231灌浆期叶片和籽粒谷氨酰胺合成酶(GS)和谷氨酸合成酶(GOGAT)活性显著高于4434和滇瑞302,有利于叶片游离氨基酸合成及外运,使得穗颈节伤流强度和游离氨基酸含量升高,为籽粒氮素积累提供了物质基础;同时,较高的籽粒GS和GOGAT活性促进了籽粒蛋白质合成,提高了NHI。逐步回归表明,灌浆期较高的穗颈伤流游离氨基酸含量是高NHI水稻氮代谢的主要生理特征,与较高的花后氮转运量和籽粒蛋白氮积累量可共同作为水稻氮素高效管理和遗传改良的可靠指标。     

不同穗型粳稻品种米质形成的生理生化特性差异

对不同穗型粳稻品种的籽粒干物质积累动态和淀粉磷酸化酶及Q酶的活性进行了研究，同时分析了供试品种在4个氮素水平下叶绿素含量变化及与稻米品质性状的关系。结果表明，籽粒干物质积累动态在品种间存在差异，直立穗型品种，由于每穗粒数多，着粒较密，在籽粒灌浆前期，起始生长势低(GR0)，全穗籽粒平均灌浆速率较低，而后期     

水稻品种源库特性与胚乳细胞增殖和充实的关系

选用不同源库类型品种,人为改变其源库比例,观察不同粒位籽粒胚乳细胞增殖和产的反应。结果表明,强势粒胚乳的细胞增殖品种间差别不大,弱势粒胚乳的细胞增殖和充实具明显的源库类型特征。剪叶、疏花和抽穗前用氮素肥料对强势粒的影响甚小,对弱热粒影响较大。其影响首要表现在弱势粒的胚乳细胞增殖上,单细胞物质量的调节幅度较小。弱势粒粒重的提高主要通过增强胚乳的细胞增殖实现。     

春小麦籽粒灌浆过程淀粉和蛋白质积累规律的初步研究

利用蛋白质含量和产量各异的３个春小麦品种，Ｒｏｂｌｉｎ、东农７７４２和新克旱９号，研究了灌浆过程中可溶性性糖、淀粉和蛋白质积累规律，结果表明：籽粒灌浆过程中可溶性糖含量由开花１４天开始逐渐减少，成熟期达最低值，品种间的差异仅表现以１４天和２０天两个时期：淀粉积累动态与可溶性糖变化规律相反，随灌浆成熟而逐渐增加，品种间差异达显著水平；蛋白质积累动态年际间稍有差异，总的趋势是随灌浆成熟而逐渐增加，开花