Improving Rice to Meet Food and Nutritional Needs: Biotechnological Approaches

SUMMARY

The livelihood and calorie needs of large populations based in developing countries is dependent on rice cultivation. More than three billion people consume rice as a staple food. To meet the future demands of the human population, innovative tools such as genomics are being used to improve rice yield increase, for the incorporation of stress resistance/tolerance in rice varieties, and for the improvement of the nutritional quality of rice. These new tools include: sequencing, large-scale analysis of expressed sequence tags, high throughout microarray analysis and genetic transformation. Rice now serves as a model for a science based crop design for the agronomic, nutritional, and economic benefit of farmers. This article discusses the use of biotechnology as a tool to improve the rice plant for the benefit of mankind.     

Domoic Acid Improves the Competitive Ability of Pseudo-nitzschia delicatissima against the Diatom Skeletonema marinoi

Because domoic acid, a neurotoxic secondary metabolite produced by marine diatoms in the genus Pseudo-nitzschia, is hypothesized to be part of a high affinity iron uptake system, we investigated whether domoic acid could improve the competitive ability of Pseudo-nitzschia delicatissima, and whether the availability of iron changed the outcome of competition experiments. We found that domoic acid had a slight negative effect on growth of the diatom Skeletonema marinoi when it was grown in monocultures. However, when S. marinoi was cultured with P. delicatissima the presence of domoic acid resulted in a reduction of S. marinoi cells by up to 38% and an increase in P. delicatissima cell numbers by up to 17% under iron replete conditions. Similar effects were not observed in low iron treatments. Domoic acid was not taken up by P. delicatissima cells. Overall, our results indicate that domoic acid can improve the competitive ability of Pseudo-nitzschia spp. and that iron is likely to be involved. This study provides an unusual example of indirect inhibition of competitor growth mediated by a secondary metabolite.     

Effect of ammonium‐iron‐hexa‐cyanoferrate and of the covariates age,gender, weight,season and calendar time on radiocaesium contamination of wild boars living in the wild in Bavaria

Feed with Ammonium‐iron‐hexa‐cyanoferrate (AFCF; 1250 mg AFCF/kg) was fed between March 2009 and March 2011 to wild boars in a territory of 4.5 km² (experimental group, EXP). One hundred and forty similar territories in the same county (500 km², spruce forest, agriculture) served as control (CON). Data for comparison from all territories were available from March 2005 to March 2011. Wild boars could move between, into and from the territories. Lean skeletal muscle meat (500 g) of all wild boars that were killed by humans (hunting and traffic accidents) was investigated for gamma‐radiation from ¹³⁷Cs with a becquerel monitor with a sodium iodide scintillator crystal (range of detection 20–9999 Bq/kg). The wild boars were weighed, and gender and age were determined. For the analyses of effects, multivariable regression models were fitted with the ¹³⁷Cs concentration as response variable. There was a significant difference between the ¹³⁷Cs contamination of wild boars from CON (563 ± 932 Bq/kg meat, n = 1253) and EXP (236 ± 276 Bq/kg meat; n = 45). ¹³⁷Cs contamination decreased with increasing body weight by ?5 Bq/kg meat/kg body weight increase (p < 0.05). Females had higher Bq measurements than males (by +80 Bq/kg meat, p < 0.05). Piglets were lower than adults, but turn‐coats higher. From November to May, contamination was higher (by +500 to +600 Bq/kg meat, p < 0.05) than during the rest of the year. In 2010, contamination was higher (by +200 to + 300 Bq/kg meat, p < 0.05) in comparison with the other years under observation. When all covariates were controlled for, the effect of AFCF was highly significant. Interaction analyses showed that the intervention decreased ¹³⁷Cs contamination by ?500 Bq/kg meat during November to May and by ?200 Bq/kg meat during the rest of the year. In summary, AFCF feeding reduces ¹³⁷Cs contamination of wild boars living in the wild significantly, particularly during the season from November to May.     

铁盐对海带雌配子体生长发育的影响

为探明铁盐对不同品种(系)以及相同品种(系)在不同生长条件下海带雌配子体的影响,通过添加不同质量浓度的Fe3+,对培养在低温弱光[(10.0±1.0)℃、2μmol/(m2·s),L]和高温强光[(15.0±1.0)℃、80μmol/(m2·s),H]条件下的"901"、韩国海带和"连杂1号"3个品种(系)海带雌配子体...     

施钙与覆膜栽培对缺钙红壤花生Mg、Fe、Zn吸收,积累及分配的影响

为探究施钙与覆膜栽培对花生植株Mg、Fe、Zn营养改善状况,以大籽品种湘花2008和南方典型第四纪红土发育的缺钙酸性红壤为试验材料,设置3个基施钙肥梯度[不施钙(Ca0)、施钙375 kg·hm^-2(Ca375)、施钙750 kg·hm^-2(Ca750)]和2种栽培方式[露地(OF)、覆膜栽培(PF)],采用土柱栽培,研究施钙与覆膜栽培对植株Mg、Fe、Zn含量,积累及籽仁分配系数的影响。结果表明,增施钙肥明显提高了花生茎秆、根系、果针、籽仁中Mg和Fe含量,其中,Ca750-OF处理较Ca0-OF分别提高19.2%、10.4%、38.6%、3.1%和21.5%、30.9%、27.5%、20.0%,但显著降低了叶、茎秆、果壳及籽仁中Zn含量。覆膜栽培提高了茎秆、果针、籽仁Mg含量及果壳、籽仁Zn含量,较露地栽培分别提高10.8%、12.2%,但降低了花生叶、茎秆、根系Fe和Zn含量。施钙与覆膜栽培增加了花生植株、生殖体(针壳、籽仁)Mg积累量、籽仁Mg分配系数。施钙实现花生整个植株体Fe积累量的富集,其籽仁Fe分配系数显著提高68.8%,而覆膜栽培籽仁Fe和Zn积累量显著高于露地栽培。增施钙肥降低了花生营养体Zn积累量,显著提高了籽仁Zn积累量及籽仁Zn分配系数,提高效果表现为Ca750>Ca375。年份、施钙处理、栽培措施三者间对籽仁积累量及分配系数存在正交互作用。植株Ca积累量与Mg、Fe积累量呈极显著正相关,存在协同吸收关系。综上,施钙与覆膜栽培促进了土壤活化,有利于花生植株中Mg、Fe的吸收,加快Mg、Fe、Zn向籽仁的富集,进一步扩大“库容”。本研究结果为南方酸性缺钙红壤旱地改良及花生高产高效栽培提供了理论依据。     

铁、锌配施对藿香生长、产量及有效成分的影响

为探究铁、锌不同浓度配施对藿香生长、产量及有效成分的影响,以藿香为试验材料,采用双因素随机区组设计,研究铁锌配施对藿香生长、产量、各部位铁锌分配及挥发油含量的影响。结果表明,叶面喷施铁锌肥能显著影响藿香的生长发育、产量和挥发油成分,显著影响藿香的抗氧化酶活性,显著提高淀粉、还原糖、可溶性糖和可溶性蛋白含量,通过影响氮代谢相关酶活性间接影响植株氮代谢过程。叶面施铁对藿香产量的影响大于叶面施锌,铁锌配施的增产效果优于单独施用铁、锌肥;综合考虑藿香的生长和产量指标,认为Fe₁Zn₁(0.2%铁,0.1%锌)为铁锌配施的最优处理组合。施用锌铁肥能够增加藿香各部位的铁锌含量,锌在不同部位的含量呈叶>根>茎的变化趋势,铁在不同部位的含量呈根>叶>茎的变化趋势,锌主要集中在藿香叶片,而铁则主要集中在藿香根部。高浓度的叶面施铁有助于叶片Ca含量的累积。铁锌配施能显著提高藿香挥发油含量,并影响挥发油成分,其中D-柠檬烯含量最高,在Fe₁Zn₂处理时达到最大值(22.99%)。综上,合理配施铁锌肥能提高藿香主要化学成分的含量,但过高浓度的施用增产效果并不明显。本研究结果为铁锌肥在藿香生产中的应用提供了理论依据。     

Effect of supplied phytosiderophore on 59Fe absorption and translocation in Fe-deficient barley grown hydroponically in low phosphorus media

Hydroponically grown barley plants ( Hordeum vulgare L. cv. Minorimugi) under iron-deficient (–Fe) and high phosphorus (P) conditions (500 µmol L⁻¹) showed Fe chlorosis and lower growth compared with plants grown in –Fe and low P conditions (50, 5 and 0.5 µmol L⁻¹). To understand the physiological role of P in regulating the growth of plants in –Fe medium, we carried out an Fe feeding experiment using four P levels (500, 50, 5 and 0.5 µmol L⁻¹) and phytosiderophores (PS), mugineic acid. Our results suggest that plants grown in a high P medium had higher absorption activity of ⁵⁹Fe compared with plants grown in low P media, irrespective of the presence or absence of added PS. Translocation of ⁵⁹Fe from roots to shoots was not affected by the P level. The relative translocation rate of ⁵⁹Fe increased with decreasing levels of P in the medium. In general, the addition of PS enhanced the absorption of ⁵⁹Fe and its translocation. Taken together these results suggest that the lower relative translocation rate of Fe in high P plants may be induced by the physiological inactivation of Fe in the roots, and the higher absorption activity of Fe in high P conditions possibly results from the response of barley plants to Fe deficiency.     

柠檬酸对三种人工合成氧化铁磷吸附特性的影响

试验采用了3种人工合成的氧化铁为材料,研究了氧化铁对磷的吸附以及柠檬酸对氧化铁磷吸附特性的影响。结果表明:3种人工合成的氧化铁对磷的吸附特性及柠檬酸对氧化铁吸附磷的影响都可用Langumir方程来描述,都达到了极显著水平。从磷的最大吸附量(Sm)、吸附反应常数(K)和最大缓冲容量(MBC)来看,未加入柠檬酸时,水铁矿对磷的吸附在容量和强度方面均为最高;而在加入柠檬酸时,3种人工合成的氧化铁对磷的吸附能力的顺序并无差别,水铁矿和针铁矿的磷Sm和MBC要比赤铁矿大很多。     

玉米生理年龄的差异对N缺乏诊断的影响

Many studies have shown that chlorophyll meter readings （CMRs） can be used to diagnose deficiencies of nitrogen （N） during the growth of corn （Zea mays L.） in small-plot trials, but there is need to address additional problems encountered when diagnoses are made in fields of the size managed in production agriculture. A noteworthy difference between smallplot trials and production agriculture is the extent to which the effects of N are confounded with the effects of other factors such as tillage, landscape, soil organic matter and moisture content. We illustrate how some of these factors can cause differences in the physiological age of plants and introduce errors in the diagnoses of N deficiencies. We suggest methods （measuring the height to the youngest leaf collar and assigning leaf numbers by using the first leaf with pubescence and the ear leaf as references to identify growth stages） for minimizing these errors. The simplified method of growth stage identification can be used to select appropriate plants and leaves for making diagnoses in fields and to distinguish the effects of N from the effects of other factors that influence plant growth.