Uneven Distribution of Zinc in the Dorsal and Ventral Sections of Rice Grain

This study examined the distribution of zinc in dorsal and ventral grain sections of rice varieties with low (RD21), moderate (CNT1 and KDML105), and high (KPK and NR) zinc concentrations. Samples of unhusked rice grain were partitioned longitudinally and analyzed for zinc. The concentration of zinc was higher in the dorsal grain section than the ventral section, but to a different extent in different varieties. In unpolished rice, the zinc concentration in the dorsal section exceeded that in the ventral section by 14% in CNT1 to 63% in RD21. The higher zinc concentration in the dorsal section of unpolished rice might be explained by storage in the multiple cell layered aleurone and thicker pericarp. The higher concentration of dorsal zinc, however, was maintained after polishing, irrespective of the removal of grain surface by polishing that varied with variety and polishing time from 11 to 207 μm in depth. Zinc concentration of polished rice, ranging from 14 to 28 mg of zinc/kg, was strongly predicted by the zinc in unpolished rice (P < 0.01). This uneven distribution of zinc in the dorsal and ventral sections of rice grain suggests a specific pattern by which zinc is laid down. Whether the region of endosperm and aleurone proximal to the dorsal vascular bundle may have a greater concentration of zinc transporters and zinc storage structures than in more distal areas is yet to be investigated. Understanding this distribution may aid efforts in zinc biofortification and evaluation of rice varieties for other nutritive characteristics.     

Rapid Variety Identification of Pure Rough Rice by Fourier‐Transform Near‐Infrared Spectroscopy

Rice variety is considered as an important factor influencing cooking and processing quality because of variations in size, shape, and constitution. Difficulty in management of rough rice with lower varietal purity becomes a significant problem in rice production and can result in the reduction of rice quality. Fourier‐transform near‐infrared (FT‐NIR) spectroscopy was used to identify the variety of rough rice through whole‐grain techniques. Moist rough rice samples (n = 259) comprising five varieties (Khao Dawk Mali 105 [KDML105], Pathum Thani 1, Suphan Buri 60, Chainat 1, and Pitsanulok 2) were gathered from different locations around Thailand and scanned in the NIR region of 9088–4000 cm^–1 in reflectance mode. Soft independent modeling of class analogies (SIMCA) and partial least squares discriminant analysis (PLSDA) methods were used for identification by utilizing preprocessed spectra. The highest identification accuracy achieved was 74.42% by the SIMCA model and 99.22% by the PLSDA model. The best PLSDA model demonstrated approximately 97% correct identification for KDML105 samples and 100% for the others. This study raises the possibility of applying FT‐NIR spectroscopy as a nondestructive technique for rapidly identifying moist rough rice varieties in routine quality assurance testing.     

Influences of irrigation,nitrogen and zeolite management on the physicochemical properties of rice

The addition of zeolite (Z) to soils is increasingly being recognised as a way to enhance agricultural production and decrease fertilisation requirements and, hence, environmental costs. Meanwhile, the alternate wetting and drying irrigation (AWD) has become widely applied to reduce the water requirements of rice cultivation. However, limited information is available on their impacts on rice’s physicochemical properties. This study investigated an integrated irrigation, nitrogen (N) and Z rice production system and assessed its effects on the milling, appearance, nutrition, taste and cooking qualities of the rice grain produced. Compared with conventional flooding irrigation (CF), AWD-grown rice had slightly decreased milling and appearance qualities. Addition of Z increased rice protein content and slightly decreased eating quality without affecting milling, appearance and cooking qualities. The highest yields achieved under AWD (9.8 t ha^?1) and CF (8.9 t ha^?1) were achieved using 105 kg N and 10 t Z ha^?1, and 105 kg N and 5 t Z ha^?1, respectively. Compared with the flooding untreated control (using 157.5 kg N ha^?1 and no Z), these two treatment regimens required 27.8% and 8.1% less water, 33.3% less N fertiliser and increased yields by 10.6% and 0.6%, respectively, without measurably affecting rice grain quality.     

Late nitrogen application increased protein concentration but not baking quality of wheat

Late application of nitrogen (N) fertilizers at heading or anthesis is usually performed to produce wheat (Triticum aestivum L.) with high bread‐making quality. However, increasing energy costs and ecological problems due to N losses call for efficient and simplified N fertilization strategies. This study aimed to investigate the effect of late N fertilization on grain protein quality and thus baking quality and to evaluate if similar wheat quality can be maintained without late N application. Field experiments with two winter wheat cultivars differing in quality groups were conducted. The fertilization treatments comprised a rate of 220 kg N ha^?1 applied in two or three doses (referred to as split N application), and 260 kg N ha^?1 applied in four doses (additional late N fertilization) with different N fertilizer types. The results show that although split N application had no effect on grain protein concentration (GPC), it affected N partitioning in the grain, increasing mainly the concentration and proportion of the glutenin fraction. As a result, baking quality was improved by split N application. Late N fertilization enhanced GPC and the relative abundance of certain high molecular weight glutenin subunits (HMW‐GS). However, it had no effect on N partitioning in the grain and did not further improve baking quality. No obvious differences were found between N fertilizer types on grain yield and quality. The N fertilization effect was more pronounced on the wheat cultivar whose baking quality was more dependent on protein concentration. In evaluating baking quality of wheat flour, gliadin and glutenin proportions were better correlated with loaf volume than the overall protein concentration.     

Physical characteristics of corn kernels as influenced by nitrogen fertilization

Abstract

Physical characteristics of corn (Zea mays L.) kernels influence end‐use. Agronomic practices including nitrogen (N) fertilization may influence kernel hardness. The objective of this study was to determine if com endosperm characteristics influence the effect of N fertilization on kernel hardness and breakage susceptibility. In 1988, six corn hybrids differing for endosperm were grown at two locations in Ohio and with two N rates (34 and 200 kg/ha). Kernels of the waxy hybrid were denser less susceptible to breakage than its near‐isogeneic normal counterpart. Soft kernels weighted less and were less dense than hard kernels, but these two hybrid classifications did not differ for breakage susceptibility. Hard kernels possessed a greater resistance to grinding than soft kernels. Increasing N fertilizer rate increased resistance to grinding and reduced susceptibility to breakage of both soft and hard endosperm types. Fertilization with N not only affects corn grain yield, but also affects physical characteristics that are important to end‐users.     

Genetic Variation and Association Mapping of Protein Concentration in Brown Rice Using a Diverse Rice Germplasm Collection

Protein is the second most abundant constituent in the rice grain next to starch. Association analysis for protein concentration in brown rice was performed using a “mini‐core” collection, which represents the germplasm diversity found in the USDA rice world collection. Protein concentration was determined in replicated trials conducted in two southern U.S. locations, and association mapping was performed by using 157 genomewide DNA markers. Protein concentration ranged from 5.4 to 11.9% among the 202 accessions. Protein variation owing to accession and accession × location interaction were highly significant. Ample variation was seen within each subpopulation by ancestry, as well as within the 14 geographic regions where the accessions originated. Accessions from Eastern Europe had the highest level of protein. Ten markers on eight chromosomes were significantly associated with protein concentration. Five of these markers occurred near known protein precursor genes or quantitative trait loci, and the other five markers were novel for the association with protein concentration in rice. The germplasm and genetic markers identified in this study will assist breeders in developing cultivars tailored for applications requiring specific protein concentration in the rice grain. The research results contribute to the potential discovery of novel rice storage protein pathways in the endosperm.     

不同生育期类型粳稻品种垩白性状对施氮水平的响应

以长江中下游地区5种生育类型中有代表性的56个粳稻品种为供试材料,研究了4种施氮水平下粳稻品种垩白性状的变化规律,并对其垩白变化的氮素敏感性及其品种类型特征进行了聚类分析和筛选评价。结果表明,在施N 0~300 kg/hm2范围内,随着氮肥水平的增加,各品种类型的垩白度呈现不同程度的上升趋势,但垩白米率的变化则因品种的生育期类型不同而异。其中,中粳品种在高氮水平下的垩白米率有所增加,而晚粳品种则有所下降。根据粳稻垩白度对氮肥响应的敏感程度,供试品种可分为迟钝型、中间型和敏感型3种;并据此推荐了利于生产实践中改善外观品质的两类品种:一类是垩白度较低且在各氮肥水平下表现比较稳定的品种,另一类在高氮肥水平下垩白度较高,但其对氮肥响应较为敏感,通过适当减少施氮量也能获得较好外观品质。     

Effects of Heat Treatments on the Milling,Physicochemical, and Cooking Properties of Two Long‐Grain Rice Cultivars During Storage

During storage, the milling, physicochemical properties, and eating quality of rice change, which is generally termed “aging.” Aged rice is preferred by processors because of better processing characteristics, and therefore there are attempts to develop accelerated aging processes. In this study, the effects of various heat treatments and their influences on the milling, physicochemical, and cooking properties of two long‐grain rice cultivars during storage were investigated with a randomized complete block design with an 8 × 5 × 2 full‐factorial treatment design. Two long‐grain rice cultivars, Wells and XP723, were treated with eight different heat treatments, including two levels of UV irradiation, two levels of autoclaving, three levels of convection oven heating, and one control, and then stored for 180 days at room temperature. The heat treatments significantly influenced all properties, including head rice yield (HRY), surface lipid content, peak gelatinization temperature, pasting properties, and cooked rice texture. All properties except HRY exhibited a significant two‐way interaction of cultivar and heat treatment. The severe autoclaving treatment resulted in rice of significantly different protein compositions when compared with the control. Storage impacted all properties except HRY and peak gelatinization temperature. Autoclaving (particularly severe autoclaving) produced samples with more distinct characteristics for most properties. Cooked rice hardness and stickiness exhibited not only significant main effects but also significant two‐ and three‐factor interactions.     

协调水稻产量和品质的植株临界氮浓度的确定

根据植株氮营养状况指导优质米生产具有重要意义。试验以五优稻4号为供试材料,以密度为主区（密度分别为每平方米18穴和25穴）,氮量为副区（氮量分别为0、75、105、135 kg hm?2）,测定水稻植株全氮、籽粒无机氮含量、水稻产量和品质等指标,以期为实现水稻丰产优质提供理论依据。结果表明:施氮量和水稻产量呈2次曲线关系,最高产量施氮量为113 ~ 119 kg hm?2,经济合理施氮量为110 ~ 116 kg hm?2;随着施氮量增加,各个时期水稻植株含氮量,收获期籽粒铵态氮和硝态氮含量显著提高,N105处理与N0处理间上述指标差异均显著（P < 0.05）,而 N105和N135处理间只有籽粒无机氮含量差异显著;施氮后籽粒蛋白质含量有增加趋势,随着施氮量增加稻米食味值下降,N135处理食味降低超过10%（P < 0.05）,其他处理间差异不显著。密度增加,水稻氮素积累量增加,产量提高了11.4%;稀植有利于提高地上部含氮量、籽粒铵态氮和硝态氮含量;稀植出米率提高了4.77个百分点（P < 0.05）,食味值有降低趋势。根据肥料效应函数以及施氮量和植株含氮量关系函数,拔节期和抽穗期,D1密度下植株临界氮浓度分别为15.26 ~ 16.18 g kg?1和22.65 ~ 25.98 g kg?1,D2密度下对应值分别为11.71 ~ 12.94 g kg?1和20.73 ~ 23.24 g kg?1。上述结果表明,合理密植有利于水稻高产,氮量过高不利于水稻高产和优质。在水稻丰产和优质的情况下,氮肥用量在91 ~ 105 kg hm?2比较合适,抽穗期叶片含氮量24.82 ~ 25.98 g kg?1（D1）和22.18 ~ 23.24 g kg?1（D2）可以作为协同实现水稻丰产优质的诊断指标。     

Protein quality of corn hybrids differing for endosperm characteristics and the effect of nitrogen fertilization 1

Corn (Zea mays L.) is an important source of protein for humans and animals. Because dent corn is highly responsive to nitrogen (N) fertilization, substantial amounts of N are used for corn production. Application of N fertilizer may reduce protein quality of corn kernels through an increase in zein content. The objective of this study was to determine if corn endosperm characteristics influence the effect of N fertilization on protein quality. In 1988, six corn hybrids differing for endosperm characteristics were grown at two locations in Ohio and with two N rates, 34 and 200 kg/ha. The waxy hybrid had a greater concentration of fraction I protein than the non‐wary hybrid. These two hybrids did not differ for other fractions except fraction III at Columbus. The soft endosperm hybrid had a higher concentration of fraction I protein than the hard endosperms hybrids. Soft and hard endosperm hybrids differed for fraction II protein for the 34 kg N/ha fertilizer rate but not the 200 kg N/ha fertilizer rate. These two classes of hybrids did not differ for fraction III protein. Increasing N fertilizer increased fraction II concentration for all hybrids. Concentrations of the other two protein fractions did not respond to fertilizer rate. The increase in fraction II concentration with N fertilization may result in a decrease of protem quality and feed value. Although all hybrids responded to N fertilizer, some hybrids had bigger increases in fraction II proteins than other hybrids.     

糙米机械破碎力学特性试验与分析

为了研究糙米机械破碎力学特性及其与籽粒结构特性的关系。采用物性测试仪对糙米的锥刺、三点弯曲、剪切、挤压4种机械破碎力学特性进行测试与分析,并对糙米和精米的破碎力学特性(三点弯曲)进行了比较。结果表明:糙米的断裂是由于内部胚乳组织不均匀,在外力作用下首先形成内部裂纹,裂纹尖端处的应力集中又进一步促进裂纹扩展,最终导致籽粒断裂;厚度为(1.0±0.5)mm的不同样品锥刺破碎力在10N左右,各样品籽粒内部的结合力相差较小,籽粒的断裂主要与厚度及胚乳特性有关,其中三点弯曲力更能反映籽粒的破碎特性,糙米的糠层对籽粒有一定的保护作用,糙米力学特性比精米好。该文为糙米储藏加工技术参数的确定提供依据。     

花后增温对双季优质稻产量和品质的影响

为明确未来气候变暖对双季优质稻产量和稻米品质的影响,采用开放式主动增温系统,早稻以金早47(常规籼稻)、两优287(杂交籼稻),晚稻以象牙香珍(常规籼稻)、万象优华占(杂交籼稻)和甬优5550(籼粳杂交稻)为试验材料,研究花后增温对双季优质稻产量和稻米品质的影响。结果表明,花后増温(早稻1.29℃,晚稻1.73℃)对早晚稻产量均无显著影响。增温条件下,早稻加工品质和垩白粒率均无显著变化,垩白度平均提高了16.0%;晚稻糙米率、整精米率、垩白粒率和垩白度分别平均提高了1.8%、3.5%、30.3%和27.2%;早晚稻蛋白质含量平均提高了6.27%,但直链淀粉含量平均降低了3.53%,淀粉颗粒的平均粒径提高了0.09 μm。增温对稻米RVA谱特征值的影响在季别和品种间存在较大变异。综上,花后增温对早晚稻产量无显著影响,有利于改善稻米的加工品质和营养品质,但降低了稻米的外观品质。本研究结果为未来气候变暖下双季优质稻的优质丰产栽培提供了理论依据。     

旱地高产小麦品种籽粒锌含量差异与氮磷钾吸收利用的关系

【目的】明确旱地条件下高产小麦品种籽粒锌含量差异与氮磷钾吸收利用的关系,为品种选育和科学施肥提供依据。【方法】于2013—2016年连续三年在黄土高原旱地进行田间试验,试验采用裂区设计,主处理为不施肥(CK)和施肥(NP),副处理为来自我国主要麦区的123个品种。施肥处理为N 150 kg/hm^2 (尿素,含N46%)、P_2O_5 100 kg/hm^2 (过磷酸钙,含P_2O_5 16%)。成熟期在每个品种中间2行随机抽取30穗小麦,连根拔起后,从根茎结合处剪断弃去根系,分为茎、叶、颖壳(含穗轴)和籽粒,称风干重。分析了样品中氮、磷、钾、锌含量,计算了养分的吸收量及转移量。【结果】施肥条件下高产小麦品种籽粒锌含量存在显著差异,高锌品种比低锌品种显著高54%。高锌品种的籽粒氮、磷含量分别比低锌品种显著高9%、7%,钾含量无显著差异,施肥使两组品种的氮含量显著提高,磷钾含量降低。高产高锌品种具有更高的籽粒和地上部氮、磷吸收能力,钾吸收能力与低锌品种相比无显著差异,施肥可使高锌品种的氮磷钾吸收量增幅高于低锌品种;两组品种间的氮、磷转移能力无显著差异,而高锌品种的钾转移能力较低,且两组品种的氮磷钾转移能力因施肥降低幅度一致。【结论】旱地条件下土壤养分供应充足时,高产高锌小麦品种的氮磷吸收能力强,钾转移能力弱,籽粒氮磷含量高,与低锌品种相比钾含量无显著差异。通过品种选育可同时提高旱地高产小麦籽粒锌和蛋白质含量,并提高磷含量。考虑到磷含量高时会降低籽粒锌的生物有效性,生产中通过施肥措施,适当调控磷肥,增加氮肥,在提高小麦籽粒氮锌含量的同时提高籽粒锌的生物有效性。     

优质小麦子粒淀粉组成与糊化特性对氮素水平的响应

在大田条件下,选用3个不同类型优质小麦品种: 豫麦47（强筋品种）、山农8355（中筋品种）和豫麦50（弱筋品种）,设置3个氮肥水平: 施N 0、15和30 g/m2,研究了小麦子粒淀粉的粒度分布、直支链淀粉组成、糊化特性及其对氮素水平的响应。结果表明,优质小麦子粒中淀粉粒的粒径分布范围为1～45 μm,其数目分布呈单峰或双峰曲线变化,体积和表面积分布均呈双峰曲线变化,峰谷位于10 μm处; 据此可将淀粉粒分为两种类型: A型大淀粉粒（10～45 μm）和B型小淀粉粒（1～10 μm）。优质小麦子粒淀粉粒组成存在显著的基因型差异。强筋品种豫麦47子粒中B型淀粉粒的比例较高,弱筋品种豫麦50子粒中A型淀粉粒的比例较高,中筋品种山农8355居中。施氮水平对优质小麦子粒中淀粉的粒度分布存在显著影响。在本试验条件下,随氮素水平的提高,强筋品种豫麦47子粒中A型淀粉粒的比例提高,而B型淀粉粒的比例下降; 增施氮肥后弱筋品种豫麦50和中筋品种山农8355子粒中B型淀粉粒的比例增大,而A型淀粉粒的比例降低,且前者变化的幅度较大。适量增施氮肥提高优质小麦子粒中的淀粉含量,氮肥用量进一步增大后,淀粉含量降低; 增施氮肥后优质小麦子粒中直链淀粉含量降低。增施氮肥对优质小麦子粒淀粉的糊化特性存在较大影响,且此影响的趋势因基因型和施氮量而异。其中强筋品种豫麦47表现为低谷粘度、最终粘度、反弹值、糊化温度和峰值时间提高,而高峰粘度和稀懈值降低; 当氮肥用量增大至30 g/m2时,糊化温度和峰值时间降低,而以粘度为单位的参数均提高。弱筋品种豫麦50表现为增施氮肥后,RVA参数呈下降趋势,与之相对应中筋品种山农8355的呈上升趋势。相关性分析表明,B型淀粉粒的数目、体积和表面积比例与高峰粘度和稀懈值存在显著正相关; 与低谷粘度、最终粘度和反弹值存在显著负相关。子粒中直链淀粉含量、支链淀粉含量和总淀粉含量与高峰粘度和稀懈值呈显著负相关,与低谷粘度、最终粘度、反弹值和峰值时间呈一定程度正相关; 直链淀粉相对含量与RVA特征参数之间的相关趋势与子粒中直链淀粉含量的趋势一致,但均未达显著水平。由此可以认为,氮肥通过调控小麦子粒中淀粉的直、支链组成和粒度分布而影响其糊化特性。     

不同氮效率水稻生育后期氮代谢酶活性的变化特征

以不同氮效率水稻基因型为供试材料,研究了两个供氮水平下水稻生育后期功能叶和茎秆的氮、可溶性蛋白浓度和氮转运量以及氮代谢关键酶的变化。结果表明:与对照相比,施氮处理能显著增加不同氮效率水稻功能叶和茎秆的氮、可溶性蛋白的浓度和氮转运量。在不同的施氮水平下,水稻从齐穗至成熟顶三叶的氮浓度降低了60%～67%;而茎秆氮在生育后期对籽粒氮的贡献取决于环境供氮水平,与对照相比施氮处理水稻从茎秆转运出的氮大幅提高,在不同的供氮水平下南光的叶片和茎秆氮转运量显著高于Elio。与对照相比,施氮处理增加齐穗期时硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、谷氨酸合成酶(GOGAT)和谷氨酸脱氢酶(GDH)的活性。随生育期的推进,四种氮代谢酶活性随之降低。南光的NR和GS酶活性显著高于Elio,但NR活性受水稻生育期和环境供氮水平的影响较大;南光的GOGAT和GDH的活性显著低于Elio。相关分析表明,NR和GS活性与功能叶和茎秆的氮转运量呈显著正相关。这就意味着水稻生育后期功能叶和茎秆的NR和GS活性高,尤其是GS活性高是筛选水稻氮高效的重要指标。     

Splitting nitrogen applications improves wheat storage protein composition under low N supply

For the baking quality of wheat flours, the composition and concentration of grain protein are crucial. It is common practice to use late nitrogen (N) application to increase grain protein concentration (GPC) and hence, improve baking quality. However, the use of N fertilizer—particularly shortly before harvest—involves environmental risks. With the suitability of GPC as a parameter for baking quality predictions being more and more questioned, there are further investigations needed considering not only the GPC but also the composition of grain protein. Gluten protein composition varies depending on genotype and environmental factors, such as weather conditions and fertilization rate. To examine whether the effect of a split N application varies under different amounts of total N supply, this study investigates the effects of split nitrogen application on grain protein concentration and composition of wheat (Triticum aestivum L. cv. JB Asano) at four different N fertilization levels (0.8; 1.0; 1.2, and 1.4 g N pot^?1) in a pot experiment. The GPC was affected by both, N fertilization level and split N application. In this experiment, the minimum GPC of 13%, which is required for class A wheat varieties, was only achieved when N supply was moderate (at least 1.2 g N per pot). Considering the storage protein composition, the split N application influenced the proportion of α‐/β‐gliadins and γ‐gliadins, the alterations being inconsistent. The ratio of high molecular weight (HMW) to low molecular weight (LMW) glutenin subunits was increased by the split N application only at the lowest N fertilization level. It is concluded that splitting N fertilization into three doses and hence applying one dose of N late in the season can still be a useful approach to improve GPC as well as protein composition – especially when the total N supply is low.     

Distribution of Protein Bodies and Phytate‐Rich Inclusions in Grain Tissues of Low and High Iron Rice Genotypes

The present study aims to understand whether genotypic differences in grain iron (Fe) concentration in four rice genotypes are related to its association with protein bodies containing phytate‐rich inclusions. Rice genotypes with high and low grain Fe concentrations in unpolished brown rice were grown in a greenhouse at Chiang Mai, Thailand, and grains were harvested at maturity. The presence of protein bodies and phytate‐rich inclusions in rice grain tissues were examined by means of light and transmission electron microscopy (TEM). The composition of mineral elements in different grain tissues was examined using energy dispersive X‐ray microanalysis (EDX) and chemical analysis. The relative distribution pattern of protein bodies in the tissues was similar among the four rice genotypes, which resembled the pattern of grain N concentrations in these tissues. The high grain Fe genotypes (based on brown rice Fe concentration) had more protein bodies containing phytate‐rich inclusions in the embryo and aleurone layer tissues than the low Fe genotypes. Phytate‐rich inclusions were not detected in the endosperm tissues in all genotypes. In conclusion, the presence of protein bodies with phytate‐rich inclusions predominantly in the embryo and aleurone regions of the grain is an important parameter contributing to the variation in brown rice Fe concentration among the genotypes, but not in the white rice (the endosperm). Iron associated with the phytate‐rich inclusions present in the embryo and aleurone layer tissues are largely lost during the polishing process to produce white rice.     

不同品种水稻的产量构成因素及其对氮磷吸收的差异研究

为筛选出适合江苏地区种植的高产、高效水稻品种,采用盆栽试验,测定了江苏地区常见的11个水稻品种的株高、产量、结实率、总干物质量以及不同部位N、P含量,分析了水稻产量与其构成因素、氮磷积累量、氮磷收获指数间的相关关系。结果表明,水稻平均产量为16.85 g pot~(-1),变化幅度为8.28~25.18 g pot~(-1),品种间产量差异显著(P0.05),其中泰瑞丰5产量最高。水稻各部位氮素含量从大到小依次为:籽粒叶≈根茎谷壳,其中苏秀9籽粒中氮含量显著高于其他品种。磷素在水稻各部位中的含量分布为:籽粒根≈茎叶≈谷壳,籽粒中的磷含量最多的是南粳5055。相关分析表明,水稻的产量与总干物质量、穗粒数、氮磷积累量及氮磷收获指数均存在显著的相关性。不同品种水稻的产量、籽粒氮磷含量存在显著差异,这为高产、高效水稻品种的筛选提供了重要的科学依据。     

Grain yield and mineral composition of corn as influenced by endosperm type and nitrogen

Abstract

Corn (Zea mays L.) is a major source of nutrition for humans and animals. Chemical and physical properties of corn endosperm vary among hybrids, are influenced by genotype and environment, and may affect the crop's response to nitrogen (N) fertilization. The objective of the study was to measure the responses of grain yield and grain N, phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn), iron (Fe), boron (B), zinc (Zn,) and copper (Cu) concentration of different endosperm types to N fertilization. The study was conducted at two Ohio locations in 1988, where six endosperm types and two N rates (34 and 200 kg N/ha) were combined in a split plot arrangement. Nitrogen rate (main plots) had little effect on yield at either location, and the soft endosperm hybrid was the only hybrid to respond to N fertilizer. Within fertilizer level, hybrids differed in grain yield with the waxy hybrid out yielding the normal endosperm hybrid, and the hard endosperm hybrid out yielding the soft one at the 200 kg N/ha rate. Application of N fertilizer increased the grain N concentration of all hybrids. Grain of the waxy hybrid contained an equal or greater N concentration than the normal hybrid. In contrast, no difference in N level was found between hard and soft endosperm hybrids at either fertilizer level. Climatic conditions and soil fertility differences might have been partly responsible for location effects. Genetic make‐up could have been a factor in differing hybrid response since grain concentration of nutrients Varied by location, endosperm type, and N treatment.     

Site of Origin of Volatile Compounds in Cooked Rice

Volatile compounds emanating from three cultivars of cooked rice milled to different degrees (0, 8, and 30% by weight) were compared to ascertain their site of origin and the effect of pigmentation on synthesis. The cultivars tested were Ilpumbyeo (traditional white rice), Heugjinjubyeo (black pigmented), and Jeogjinjubyeo (red pigmented). In total, 29, 38, and 27 volatile compounds were identified in dehulled, unmilled Ilpumbyeo, Heugjinjubyeo, and Jeogjinjubyeo, respectively. Significant quantitative and qualitative differences were found among the cultivars in their volatile profiles. 2‐Acetyl‐1‐pyrroline, guaiacol, 1‐nonanol, 3‐octen‐2‐one, 1,2‐dimethoxybenzene, pyridine, and pyrrole were found only in Heugjinjubyeo and phenylacetaldehyde only in Jeogjinjubyeo. Removal of the bran, partial endosperm, and pigment qualitatively and quantitatively affected the volatile compounds formed, with certain volatiles higher in unmilled rice (0% milling), indicating the pericarp and aleurone layer (bran) as their primary site of origin. Volatiles emanating from the 8 and 30% milled samples indicated the outer and middle endosperm (8%) and core endosperm (30%) as the primary sites of origin. Therefore, differences in chemical composition with location within the grain appear to account for the quantitative and qualitative variation in volatile synthesis.