Partitioning of photoassimilates by potato plants (Solanum tuberosum l.) as influenced by irradiance: II. Partitioning patterns by four clones grown under high and low irradiance1

This paper is the second in a three-part series describing the influence of varied irradiance on growth and photoassimilate partitioning by potato plants. Four clones (Russet Burbank, Lemhi Russet, A66107-51, and A6948-4) were grown under two light regimes: a) high light levels (HL) of 500 to 1200 μE m^-2 s^-1, varying with changes in natural sunlight and time of day, and b) low light levels (LL) at approximately one quarter of high light (21 to 28%). Three weeks after tuber initiation, the most recently-matured leaf was labelled with¹⁴CO₂, and plants were harvested: 1) one day after labelling, and 2) two weeks after labelling. Plants of all clones responded to the low light levels in a similar way by: 1) changing some morphological characteristics, 2) decreasing biomass accumulation and tuber yield, and 3) changing the sink-source relationship by promoting growth of leaves and stems at the expense of tubers. However, there were evident clonal differences in reactions to growth under low light; e.g., Lemhi Russet appeared to be most sensitive to light stress, while clones A66107-51 and A6848-4 were much less sensitive. No matter what the prior light history (HL or LL), clone A6948-4 was able to maintain higher rates of photosynthesis than the other clones at all light levels between 200 and 1200 μE m^-2 s^-1. This study showed that the potential exists to breed for cuttivars that can maintain higher rates of photosynthesis and higher tuber yield under low light levels.     

三相分离法提取胡椒油树脂的工艺研究

本文以黑胡椒粉为原料,采用三相分离法（TPP）提取胡椒油树脂,研究了胡椒粉添加量、硫酸铵质量浓度、提取液与叔丁醇体积比、pH、温度对胡椒油树脂得率及胡椒碱含量的影响,并通过响应面试验优化了胡椒油树脂的提取工艺。结果表明：最佳提取条件为胡椒粉添加量5%、硫酸铵质量浓度10%、提取液与叔丁醇的体积比1∶0.5、pH 4、温度20℃,在此条件下,黑胡椒油树脂得率为12.90%,黑胡椒油树脂中胡椒碱含量为30.46%,验证试验与模型预测值基本相符。研究结果为工业化提取胡椒油树脂提供参考。     

Stomatal resistance of three potato cultivars as influenced by soil water status, humidity and irradiance

Summary Leaf stomatal resistance varies considerably in response to changes in environmental conditions. Understanding cultivar differences in the response of stomata to these conditions is important for effectively simulating water-use and growth. In this study the stomatal resistance of three field grown potato (Solanum tuberosum L.) cultivars Atlantic. Monona and Norchip was observed in response to photosynthetic photon flux density, leaf to air vapour pressure difference and root zone available soil water. Substantial variation in stomatal resistance was accounted for by functions of the environmental variables for both Monona and Norchip. The explained variation for Atlantic was considerably less. Light saturation occurred near 500 μmol m⁻² s⁻¹. Increasing stomatal resistance above 1000 μmol m⁻²s⁻¹ was also observed but is likely an artifact of stomatal closure on days in which mid-day leaf water potentials dropped below critical levels. Although the leaf presumably insufficient to obtain substantial effects. The soil water status was partially linked to the average 1000 h to 1500 h stomatal resistance on clear, sunny days. Significant differences were observed among the cultivars in the response of stomata to changes in the available soil water.     

荔枝树体内P素的分布及积累特点

把采果后的9龄妃子笑和黑叶荔枝树植株,以及3龄未结果幼年妃子笑植株的根、茎、叶3个器官分成16～20个部位和组织,分别测定各个部位和组织的生物量及P含量,并计算其P累积量,研究荔枝树体内P素在各个部位、组织中的分布及积累特点.结果表明:(1)P含量因组织和部位而异,在末级侧枝木质部、新成熟小叶中最高,在根颈、主茎木质部中较低;随着荔枝枝干和根系粗度增加,其P含量基本上呈下降趋势;(2)9龄妃子笑植株的末级侧枝木质部和叶中的P含量高于3龄树相应部位的P含量;(3)9龄荔枝树体内P累积量以茎中为最多,其次为叶片,根系中的P累积量最少,其中茎中木质部P积累量远大于韧皮部;3龄妃子笑植株树体内叶和茎的P累积量差异不大;(4)9龄妃子笑植株末级侧枝(包括其叶)的P累积量占整株树P累积量的50%以上.     

Carbon dioxide effects on potato growth under different photoperiods and irradiance

Carbon dioxide concentration can exert a strong influence on plant growth, but this influence can vary depending on irradiance. To study this, potato plants (Solanum tuberosum L.) cultivars Norland', Russet Burbank', and Denali' were grown in controlled-environment rooms at different levels of CO2 and irradiance. Carbon dioxide levels were maintained either at 350 or 1000 micromoles mol-1 and applied in combination with 12- or 24-h photoperiods at 400 or 800 micromoles m-2 s-1 photosynthetic photon flux. Air temperatures and relative humidity were held constant at 16 degrees C and 70%, respectively, and plants were harvested 90 d after planting. When averaged across all cultivars, CO2 enrichment increased tuber yield and total plant dry weight by 39 and 34%, respectively, under a 12-h photoperiod at 400 micromoles m-2 s-1; 27 and 19% under 12 h at 800 micromoles m-2 s-1; 9 and 9% under 24h at 400 micromoles m-2 s-1. It decreased dry weights by 9 and 9% under 24 h at 800 micromoles m-2 s-1. Tuber yield of Denali showed the greatest increase (21%) in response to increased CO2 across all irradiance treatments, while tuber yields of Russet Burbank and Norland were increased 18 and 9%, respectively. The results show a pattern of greater plant growth from CO2 enrichment under lower PPF and a short photoperiod.     

大麦植株干物质分配模型

为给建立大麦产量品质形成预测模型奠定基础,通过定量分析不同品种和氮肥处理大麦干物质分配和转移的变化过程,建立大麦植株干物质分配动态模型.模型采用Richards方程描述大麦干物质分配指数的动态变化,引入叶片潜在分配指数、茎鞘潜在分配指数、籽粒潜在分配指数3个品种遗传参数反映不同品种在器官间的干物质分配差异;采用两段Richards方程来描述大麦茎鞘在灌浆期前后的干物质分配动态,较好地解决了两段方程的衔接问题;运用氮素影响因子来校正不同氮素水平对大麦干物质分配的影响,引入潜在临界含氮量和潜在最小含氮量2个品种遗传参数来表达氮素对不同品种干物质分配影响的差异.利用不同品种、氮肥、播期和种植地域试验数据检验模型.结果表明,大麦干物质在叶片、茎鞘、穗和籽粒间分配模拟值与观测值的绝对预测误差为0.001～0.252 kg·m-4,RMSE为0.007～0.186 kg·m-2,精度良好.模型体现出较好的可靠性.     

小麦器官间干物质分配动态的定量模拟

干物质分配是作物生长模拟模型中的关键成分。本文根据对大量试验资料的分析与处理，建立了小麦一生中各器官分配指数随生育进程连续变化的动态关系，并以收获指数作为遗传参数调节不同品种穗部的分配比例，从而预测不同品种各器官的物质增长动态。模型的检验结果表明，模拟值与观察值之间具有较高的符合度，平均相对误差小于8%。     

Partitioning of glutenin flour of special wheat using aqueous two-phase systems

The partitioning behavior of the glutenin proteins was evaluated in aqueous two-phase systems (ATPSs) formed by sulfate salts (lithium or sodium) and poly(ethylene glycol) (PEG) with average molar mass of 1500 g mol⁻¹ or 4000 g mol⁻¹. The partition coefficients for the glutenin proteins in each ATPS were investigated as a function of the temperature (278.2 K–318.2 K), tie line length (TLL) and electrolyte nature. In all ATPS, the majority of glutenin proteins spontaneously concentrate in the polymer-rich phase (K_p > 1). The partition coefficient is very dependent on the salt nature and the ATPS formed by PEG + lithium sulfate presents higher K_p values as compared with the ATPS formed PEG + sodium sulfate. An increase of molar mass of polymer promotes a decrease of K_p. Thermodynamic parameters of transfer (Δ_trG, Δ_trH and Δ_trS) were obtained by the application of the Van’t Hoff equation (VHE). The values obtained by VHE indicate that the transfer of glutenin proteins to the polymer-rich phase has an enthalpic origin.     

Stomatal conductance and gross photosynthesis of potato (Solanum tuberosum L.) as influenced by irradiance,temperature, and growth stage

Summary Stomatal conductance (SC) and gross photosynthesis (P_G) of two potato clones were measured simultaneously with a dual-isotope porometer. Maximum P_G rates by Russet Burbank in the field were at intermediate levels early in the season, nearly doubled during mid-season, and declined during August. Maximum SC and P_G rates by Russet Burbank in the field occurred about 11h00, although leaf temperature did not reach its maximum unit¹ about 16h00. P_G rates by Russet Burbank in the glasshouse were maximum at about 24–30°C; SC was maximum by about 24°C and remained relatively constant at higher temperatures even though P_G declined. Clone A6948-4 had higher P_G rates in the field than Russet Burbank under all conditions and did not reach maximum levels until 1350 μE. The P_G response by Russet Burbank to varied irradiance in the glasshouse was similar to its response in the field.

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Zusammenfassung Die stomatale Leitf?higkeit (SC) und die Bruttophotosynthese (P_G) von zwei Kartoffelklonen (Solanum tuberosum L. — Russet Burbank und A6948-4) wurden gleichzeitig mit einem Dual-Isotop-Porometer gemessen. Die maximalen P_G-Raten von Russet Burbank im Feld waren anfangs Saison mittleren Grades, w?hrend der Saisonmitte fast doppelt und im Lauf des Augustes nahmen sie ab (Abb. 1). Die maximalen SC- und P_G-Raten von Russet Burbank im Feld wurden um etwa 11 Uhr vormittags erreicht, obwohl die Blattemperatur ihr Maximum erst ungef?hr um 4 Uhr nachmittags erzielte (Tabelle 1). Die P_G-Raten von Russet Burbank im Glashaus waren bei ca. 24–30°C maximal; das Maximum von SC war ungef?hr bei 24°C und blieb bei h?heren Temperaturen relativ konstant, selbst wenn P_G abnahm (Abb. 2). Offenbar kann die Abnahme von P_G nicht Aenderungen in SC zugeschrieben werden, sondern muss auf eine direkte Temperaturhemmung von P_G zurückgeführt werden. Die P_G-Reaktion von Russet Burbank auf unterschiedliche Einstrahlung im Glashaus war gleich wie ihre Reaktion im Feld. Im Gegensatz zu manchen C₃-Spezies nahm die SC von Russet Burbank mit steigender Einstrahlung von 400 auf 1700 μE m² s¹ zu (Abb. 3). Vergleichende SC-Messungen mit Kartoffeln müssen offenbar bei konstanten und bekannten Lichtstufen vorgenommen werden. Die SC- und P_G-Reaktionen auf die Einstrahlungsstufen (Abb. 3) deuten darauf hin, dass Russet-Burbank-Pflanzen einen überm?ssigen stomatalen Wasserverlust haben und dass SC unter Feldbedingungen vielleicht ohne jede Reduktion in P_G reduziert werden k?nnte. Der Klon A6948-4 hatte h?here P_G-Raten im Feld als Russet Burbank unter allen Bedingungen und erreichte die maximalen Grade nicht bis 1,350 μE (Abb. 4). Diese Vergleiche illustrieren die natürliche Variabilit?t, die in Kartoffelzüchtungsprogrammen vorhanden ist, und best?tigen den Wert des Screenings, um jene auszulesen, die als Elternmaterial für Kreuzungen am nützlichsten sind.

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Résumé La conductance des stomates (SC) et la photosynthèse brute (P_G) de deux clones de pommes de terre (Solanum tuberosum L. —Russet Burbank et A6948-4) ont été mesurées simultanément en utilisant un poromètre à isotope dual. Les intensités maxima de P_G pour Russet Burbank, au champ, se situaient à des niveaux intermédiaires en début de saison, étaient pratiquement doubles en milieu de saison, puis déclinaient en ao?t (fig. 1). SC et P_G atteignaient leur maxima au champ vers 11 heures du matin, alors que la température des feuilles ne parvenait à son maximum que vers 4 heures de l’après-midi (tableau 1). En serre, pour Russet Burbank, P_G était maximum vers 24–30°C; SC était maximum vers 24°C puis restait constant aux températures supérieures, tandis que P_G diminuait (fig. 2). Apparemment, la diminution de P_G ne pouvait être attribuée à des variations de SC mais devait être d?e à une inhibition directe de P_G par la température. Pour Russet Burbank, la réponse de PG en serre à une variation de l’irradiation était identique à la réponse au champ. Contrastant avec de nombreuses espèces C₃, chez Russet Burbank, SC a augmenté avec l’irradiation de 400 à 1700 μEm² sec¹ (fig. 3). Pour les pommes de terre, les mesures comparatives de SC doivent de toute évidence être effectuées à des niveaux constants et connus d’éclairement. Les réponses de SC et P_G aux différents niveaux d’irradiation (fig. 3). suggèrent que les plantes de Russet Burbank perdraient trop d’eau par les stomates et que l’on pourrait peut être réduire SC dans les conditions du champ sans réduire P_G d’aucune fa?on. Quelles que soient les conditions, le cone A6948-4 avait des niveaux de P_G plus élevés au champ que Russet Burbank et n’atteignait un maximum que pour 1,350 μE (fig. 4). Ces comparaisons illustrent la variabilité naturelle que l’on rencontre dans les programmes d’hybridation des pommes de terre, et qui établit la valeur discriminante pour choisir quels seront les matériels parentaux les plus utiles pour les croisements.

     

碳水化合物的分配在玉米杂交种耐低氮中的作用

探明玉米耐低氮的生理机制有利于促进氮高效遗传改良的进度.本试验选用对氮反应有典型差异的两个玉米杂交种西玉3号和高光效1号,采用盆栽试验,设3个氮水平,探讨了苗期玉米对低氮环境的适应性机制,结果表明:两品种在高低氮条件下的地上部干物重差异都不显著,但冠/根比存在显著差异.在低氮下西玉3号的根长、根表面积及根重增加幅度大,超过高光效1号,因而它具有较强的截获氮素养分的能力,以适应低氮环境.低氮下西玉3号有较大的叶面积,可产生大量的光合产物.其叶片光合产生的可溶性糖向根系的大量运输,即有利于根系生长,又可以为氮的吸收同化提供充足的能量和碳架。     

供锌水平对水稻生长和锌积累和分配的影响

通过对3个不同水稻品种（碧玉早糯、26715和浙农921）5个供锌水平（0.0、0.5、2.0、8.0、32.0 μmol/L ZnSO[sub]4[/sub]）处理的水培试验,研究供锌水平对水稻生长和锌积累的影响。结果表明,水稻地上部锌含量随供锌水平的提高而提高,不同的供试品种在不同的生育期地上部锌含量的变化趋势存在差别。不同的供试品种之间籽粒锌的积累差异极显著,精米中的锌含量随供锌水平的提高而提高;在8.0、32.0 μmol/L Zn水平下,籽粒锌含量差异不大,颖壳锌含量则随供锌水平的提高而提高;在≤8.0 μmol/L时,精米锌含量比颖壳高,而在高锌水平（32.0 μmol/L）下,颖壳的锌含量比精米高。     

Effects of photoperiod,night temperature,and irradiance on flower production in the potato

Summary The influence of three environmental factors on the incidence of arrested floral development (bud abortion) in different potato clones was studied. The first experiment measured flower production in growth chambers when a 12-h photoperiod was extended by 4 h dim light. The second experiment, also in growth chambers, contrasted flower production under night temperatures of 10°C and 20°C (day temperature 30°C, photoperiod 12 h). A third experiment examined bud abortion in plants grown in the greenhouse under shade cloths which reduced incoming irradiance to ca. 50% of normal. Both the longer photoperiod and warmer night temperature promoted flower production, in some of the clones tested, by reducing bud abortion. Reduced irradiance completely suppressed flower development (but not bud formation) in all clones. In all experiments, the number of flowers developing to anthesis was significantly correlated with shoot dry weight, indicating that treatments which promote shoot growth reduce the incidence of bud abortion. Paper No. 854, Department of Vegetable Crops, Cornell University.     

Influence of irradiance on branch growth of white clover stolons in rejected areas within grazed swards

Development of white clover stolons ( Trifolium repens ) was compared when grown in rejected areas and in adjacent defoliated areas over 28 days in May - June in continuously stocked grass/white clover swards. In the cut areas more branches were borne on stolons with more but shorter internodes and shorter petioles than in the rejected areas. Red (R)/far red (FR) ratio at the base of the cut sward was significantly higher than in the rejected sward.
Five experiments were carried out in which red light-emitting diodes (LEDs) supplied supplementary irradiation at the node of the youngest fully expanded leaf on white clover stolons growing in association with dense canopies of perennial ryegrass. Axillary bud/branch length was the only significantly affected aspect of development that was measured, irradiation enrichment increasing length by about three-fold over a 2–4 week period. One of the experiments involved identification of the site of perception of the R/FR effect. Natural and supplementary light were excluded from the stolon (by covering with a 2-cm layer of black beads), petiole (by wrapping in aluminium foil), both or neither and showed that exposure of the stolon/ petiole base to supplementary light was necessary to stimulate axillary bud growth.
It is concluded that the relative content of red light, and possibly absolute level, in irradiance at the base of the canopy in rejected areas is implicated in the young branch growth and that release of the buds can be achieved by defoliation, presumably due to increasing the red light content; however, the effect of increased photosynthetically active radiation (PAR) reaching stolons and young leaves cannot be discounted as an additional factor.     

Different Nitrogen Sources Affect Biomass Partitioning and Quality of Potato Production in a Hydroponic System

Crop production systems should reduce nitrogen application costs and assure that the appropriate form of nitrogen is used. Thus, three potato cultivars in a hydroponic system were supplied with two different nitrogen sources to determine the effect on biomass accumulation and partitioning, and total plant nitrogen content. Cultivars Agata, Atlantic and Bintje received, on alternate days, nutritive solutions differing only in either calcium nitrate or urea. Urea stimulated biomass accumulation and total nitrogen in shoots. Moreover, urea reduced the ratios tuber:shoot and tuber:root, and increased the ratio shoot:root, indicating competition for biomass partitioning between shoots and tubers. Urea stimulated greater tuber volume in the Atlantic cultivar, and increased tuber protein content, which is undesirable for industry. These results suggested that salts containing nitrate could be more appropriate for hydroponic potato cultivation, since urea compromised tuber quality and biomass partitioning in all cultivars studied.     

Dry Matter Partitioning to Stem at Full Maturity Affects Stem Desiccation and Combine Harvest Maturity in Soybeans

Abstract

Days from full maturity to combine harvest maturity (DFC) is a major concern in combine harvesting of soybeans (Glycine max (L.)), especially in northern Japan, which has a short harvesting period. The combine harvest maturity, which was defined as the day at which the moisture content of the stem reached 30%, was analyzed using 7 soybean varieties for 3 yr in Hokkaido. There were significant differences in DFC among varieties (12 to 31 d) and among the 3 yr (16 to 25 d). DFC was closely associated with dry matter partitioning to stem (DMPS) at full maturity, that is, high DMPS increased DFC. The relationship between DMPS and DFC was examined by pod removal experiments conducted for 2 yr. In the soybean plants with high DMPS pod removal increased the stem desiccation period and DFC. These results indicated that DMPS at full maturity is an informative indicator for predicting the harvest maturity in the combine harvesting system.     

Dry Matter Partitioning and Harvest Index Differ in Rice Genotypes with Variable Rates of Phosphorus and Zinc Nutrition

Phosphorus(P) and zinc(Zn) deficiencies are the major problems that decrease crop productivity under rice-wheat cropping system. Field experiments were conducted to investigate impacts of P(0, 40, 80 and 120 kg/hm~2) and Zn levels(0, 5, 10 and 15 kg/hm~2) on dry matter(DM) accumulation and partitioning, and harvest index of three rice genotypes ‘fine(Bamati-385) vs. coarse(F-Malakand and Pukhraj)' at various growth stages(tillering, heading and physiological maturity). The experiments were conducted at farmers' field at Batkhela in Northwestern Pakistan for two years in summer 2011 and 2012. The two year pooled data reveled that there were no differences in percent of DM partitioning into leaves and culms with application of different P and Zn levels, and genotypes at tillering. The highest P level(120 kg/hm~2) partitioned more DM into panicles than leaves and culms at heading and physiological maturity stages. The highest Zn level(15 kg/hm~2) accumulated more DM and partitioned more DM into panicles than leaves and culms at heading and physiological maturity stages. The hybrid rice(Pukhraj) produced and partitioned more DM into panicles than F-Malakand and Bamati-385 at heading and physiological maturity stages. Higher DM accumulation and greater amounts of partitioning into panicles at heading and physiological maturity stages was noticed with increase in P and Zn levels, and the increase was significantly higher in the coarse rice genotypes than fine. We concluded that the growing hybrid rice with application of 120 kg/hm~2 P + 15 kg/hm~2 Zn not only increases total DM accumulation and partitioned greater amounts into the reproductive plant parts(panicles) but also results in higher harvest index.     

Partitioning and conversion of 14C-photoassimilates in developing grains of wheat plants grown under field conditions in Cuba

Understanding the patterns of source–sink relationships in wheat under field conditions is crucial to determine the physiological factors limiting grain filling. The aim of this investigation was to assess the time-course of source–sink interactions in wheat after anthesis under Cuban field conditions. For this purpose, plants of wheat, cultivar Cuba C-204, were sown in the field at six dates with contrasting temperature conditions. The duration of grain filling, patterns of partitioning of ¹⁴C-photoassimilates between organs and incorporation of the label into starch in the kernels 24 h after feeding the flag leaf blade with ¹⁴CO₂, were investigated to evaluate source–sink balance. The proportion of ¹⁴C converted into starch in the kernels increased during the first 10 days of grain filling. Throughout the grain filling phase the proportion of total ¹⁴C fixed partitioned to the grains increased, whereas that allocated to the internodes decreased. At the beginning of grain filling, the patterns of ¹⁴C-photoassimilate partitioning differed among sowing dates. Additionally, the proportion of ¹⁴C incorporated into starch in the kernels correlated positively with the proportion of the label partitioned to the grains, but negatively with ¹⁴C accumulation in the internodes. This supports that the accumulation of ¹⁴C in the stem was closely related to the uptake capacity of the grains. The lack of such a relationship at later stages in grain development indicates a change from sink-limited to source-limited situation early after anthesis. In conclusion, the supply of photoassimilates under field conditions in Cuba limits grain filling, except the first days after anthesis, when it was sink-limited.     

Correlation of Nitrogen Concentration with Dry-Matter Partitioning to Spikelets and Total Husk Volume on the Panicle in Japonica Rice

Summary

A rice husk restricts the grain development physically. We examined the correlation of the total husk volume on a panicle, a parameter of yield capacity, with the nitrogen concentration (per dry weight) and the dry weight of the above-ground part of the plant, using single-stem-trained japonica rice (cv. Nipponbare) plants. The growth of rice plants was regulated by shading at two levels and nitrogen application at three levels from about 40 days before the heading (about 10 days before the panicle initiation). The number of spikelets per dry weight of the above-ground part of the plant at the end of the spikelet differentiation stage was linearly correlated with the nitrogen concentration at that time. The ratio of the spikelet dry weight at heading to the dry weight of the above-ground part of the plant at the end of the spikelet differentiation stage increased as the nitrogen concentration increased at a low nitrogen concentration, but the increase of the ratio slowed down at a nitrogen concentration of 2%. Decrease in dry weight of the spikelet resulted in a decrease of lemma size. Therefore, the ratio of the total husk volume on a panicle to the plant dry weight at the end of spikelet differentiation stage also increased as the nitrogen concentration increased at a low nitrogen concentration, but the increase stopped at a nitrogen concentration of 2% in contrast to the ratio of the spikelet number to the dry weight of the plant. These results suggest that, to increase the total husk volume on a panicle by nitrogen application, dry-matter production must be increased by the nitrogen application.     

Effect of Phosphorus Deficiency on Leaf Photosynthesis and Carbohydrates Partitioning in Two Rice Genotypes with Contrasting Low Phosphorus Susceptibility

Phosphorus (P) deficiency is one of the major limiting factors to the crop production in most of the soils throughout the world [1]. The traditional way to alleviate P deficiency is the application of P fertilizer. However, the scarcity of P mineral resou…