氟对茶树生长、叶片生理生化指标与茶叶品质的影响

以2个茶树品种为试验材料,通过土壤盆栽试验,研究了土壤添加氟浓度为0～200 mg/kg对茶树生长、叶片生理生化指标与茶叶品质的影响以及茶树的氟累积特性。结果表明,随氟处理浓度增加,茶树的生长、叶绿素合成和光合作用均受到明显抑制; 福鼎大白茶的SOD、CAT和POD活性均随氟处理浓度的增加呈先升高后降低趋势,名山白毫的3种酶活性则受到明显抑制。2个品种的新梢中游离氨基酸、儿茶素组分和咖啡碱含量也随施氟浓度的增加总体呈下降趋势,茶叶品质降低,表明氟可能抑制茶树儿茶素的合成代谢和氮素代谢。茶树的氟累积量也随着土壤氟水平的增加而增加,且各器官的氟含量(y)与土壤中添加的氟(x)呈显著或极显著线性正相关; 茶树的聚氟能力依次为叶片＞新梢＞枝条＞茎＞根,叶片是氟累积的主要器官。福鼎大白茶耐氟、抗氟的能力明显强于名山白毫,但氟积累能力则低于名山白毫。     

不同茶树品种吸收累积镉的差异研究

为了解不同品种茶树对镉的响应差异,比较了9个当前主栽茶树品种对Cd吸收累积的差异特征。采用盆栽试验方法研究了不同品种茶树在对照、Cd处理(土壤Cd含量1 mg·kg~(-1))条件下,茶树地上部分干物质质量、Cd在茶树各部位的含量、富集转运系数以及茶树根部镉相关转运蛋白基因的表达。结果表明,Cd处理下不同茶树品种地上部分干物质质量出现不同程度增加。两种处理下,Cd在茶树中的分布趋势均表现为根枝干成熟叶新梢,Cd处理下,这四个部位平均Cd含量分别为32.79、0.293、0.112、0.044 mg·kg~(-1)。Cd处理下,土-根的富集系数和根-枝干、根-成熟叶、根-新梢的转移系数范围依次为7.17～30.12、0.017～0.078、0.002～0.007、0.000 3～0.006 1。CsZIP1、CsZIP2、CsHMA2、CsCAX2在紫鹃中表达量最高,CsHMA1在中茶108、乌牛早、紫鹃、浙农117表达差异不显著。综上,当茶园土壤0.3≤Cd≤1.5 mg·kg~(-1)时,不同品种茶树的新梢Cd含量都远低于国家标准限值(Cd≤1mg·kg~(-1)),处于安全范围内。     

凤凰单枞茶树吸收土壤铬和锰的规律研究

[目的]探究凤凰单枞茶树对土壤中铬和锰的吸收规律,为综合防治茶园土壤Cr和Mn污染提供科学依据。[方法]对粤东揭阳市揭东县宝山茶园凤凰单枞茶树和土壤进行采样,运用原子吸收分光光度计法测定茶叶、茶茎和茶根中Cr和Mn的含量,并采用乙酸提取法和原子吸收分光光度计法测定土壤样品中酸可提取态Cr和Mn的含量。[结果]茶树各器官Cr含量由高到低分布情况依次为:茶根>茶茎>茶叶;而Mn含量分布情况依次为:茶叶>茶茎>茶根。茶叶中Cr和Mn含量与土壤中酸可提取态Cr和Mn呈显著正相关性,茶茎中Cr含量与土壤中酸可提取态Cr也呈显著正相关性;茶叶、茶茎和茶根中的Cr含量均与土壤中有机质含量呈显著正相关性,茶根中的Mn含量与土壤pH值呈显著负相关性,茶叶中的Mn与土壤有机质呈显著正相关性。[结论]通过调节土壤酸可溶解态Cr和Mn,土壤pH值和有机质含量,从而控制茶树吸收Cr和Mn的量,可以达到防治茶叶重金属污染,提高茶叶质量的目的。     

~(134)Cs在茶树上的行为

茶树喷洒~(134)Cs后,~(134)Cs在老茶叶上的残留和新茶叶上的吸收都遵循一级反应动力学模式。~(134)Cs叶面污染后危害性最大,水质污染和土壤污染具有潜在的危害性。茶树对~(134)Cs的富集能力低,K值为0.02;鲜茶叶经制茶加工后,~(134)Cs的损失率达13.3％;茶叶经4次浸泡后,~(134)Cs的总浸出率为83.6％。     

水稻品种间吸收和转运硒特性差异机制研究

采用溶液培养试验比较了富硒水稻与非富硒水稻对硒的吸收和运输特征,期望揭示富硒水稻秀水48和非富硒水稻丙9652籽粒硒累积差异部分生理机制。结果表明,两品种水稻根部对硒吸收的Km值差异不大,但富硒水稻秀水48的Vmax是非富硒水稻的1.57倍,两品种水稻根系对硒的共质体吸收皆受载体调控。硒吸收时间动力学试验证实秀水48茎中硒的浓度和含量在各个处理时间段均要高于丙9652,富硒水稻秀水48的木质部汁液中硒的浓度大约是非富硒水稻丙9652的2倍,在相等蒸腾速率的条件下,秀水48地上部硒含量显著高于丙9652,说明两品种水稻向地上部转运硒的能力差异显著,秀水48更易将根中的硒转运到地上部,高效的转运体系是富硒品种地上部硒含量高的关键所在。富硒水稻具备很强的向地上部转运硒的能力,部分原因在于其根部木质部对硒的装载能力较强。     

茶苗对重金属Pb Cu Cd和Cr的吸收累积规律

通过盆栽实验,从动态角度研究了在不同培养期内,Pb、Cu、Cd和Cr4种重金属在茶树中的累积规律。结果表明,茶树不同部位对4种重金属的累积量存在很大差异,重金属的分布顺序为根〉茎〉叶;4种重金属大部分被茶树根系固定,在其体内的迁移性较低,在茶叶中积累的顺序为：Cr〉Cu〉Cd〉Pb。茶叶中重金属累积量和重金属添加量、培养时间都存在显著的正相关关系。4种重金属元素中,Cr的累积速率常数最大,Cd最小。茶树对重金属的吸收与土壤pH值和土壤有效态重金属含量显著相关。本研究可为人们科学认识茶叶中重金属的残留问题、健康风险及其污染控制提供理论依据。     

无性系良种茶种植推广技术分析

近年来,茶叶工作者一方面对茶树优质品种的选育和繁育十分重视,另一方面对无性系良种茶种植推广技术的研究工作也在不断推进。在此背景下,主要从无性系良种茶种植的推广意义和推广技术与实践展开讨论,并对具体的推广效果和评价进行概括性总结。     

氟胁迫对茶树氟吸收累积特性及生理生化指标的影响

以龙井43茶树为供试材料,采用水培法试验,研究了不同浓度的氟(F)胁迫对茶树叶片的抗氧化能力、膜脂过氧化以及茶树氟含量的影响。结果表明:氟胁迫促使茶树叶片的超氧化物歧化酶(SOD)活性先升高后保持相对稳定,过氧化氢酶(CAT)、过氧化物酶(POD)和抗坏血酸过氧化氢酶(APX)活性先升高后降低。氟胁迫下茶树的H202、丙二醛(MDA)以及脯氨酸(Pro)含量升高。茶树根部和地上部分氟含量均随着氟胁迫浓度的增加而增加,且各器官的氟含量(Y)与氟添加浓度(X)呈极显著正相关。富集系数和转运系数均大于1,说明茶树对氟有较强的富集能力。低浓度氟胁迫可以有效刺激茶树体内抗氧化酶活力,而高浓度氟胁迫下茶树叶片的抗氧化防御系统不能清除过多的活性氧化物。     

喷施硅肥对茶树生长及硅素分布的影响

【目的】研究喷施硅肥对茶树生长和茶叶品质的影响,以及硅在茶树中的累积和分布,为优质安全茶叶生产提供依据。【方法】采用室内盆栽与田间试验相结合的方法,供试硅肥为硅酸钠(Na2SiO3·9H2O)。室内盆栽试验设置7个硅喷施浓度：0、50、150、300、500、750、1500 mg/L,每7天喷施一次,共喷施3次。通过测定茶苗生物量、SPAD值、叶绿素荧光特性、植保素含量及气孔特性,以确定最佳喷施硅肥浓度。然后,以该最佳喷施浓度进行室内茶苗盆栽和田间试验,在室内试验中测定了茶苗不同部位和组织的硅含量,在田间试验中测定了茶园春、夏、秋季茶叶产量及新梢品质成分。【结果】喷施硅300、500 mg/L处理的茶苗地上部和根部生物量高于其他处理,幼苗叶绿素含量、叶片光化学猝灭系数(qP)、非光化学荧光淬灭系数(qNP)、表观电子传递速率(ETR)及植保素含量也高于Si0和其他处理,综合茶苗生长和生理指标结果,选用500 mg/L作为最佳硅喷施浓度。第一次喷施硅肥7天后,硅主要积累在叶部,从顶芽往下数的不同叶位硅含量分布为第3叶>第5叶>第1叶;第三次喷施7天后,第5叶硅含量显著高于第...     

树冠微域环境对茶树碳氮代谢的影响

【目的】树冠微域环境对植物的生长有着显著影响,改善植物树冠环境可提升收获对象的品质。因此茶树的生长特别是其碳氮代谢及茶叶品质可能会受到树冠微域环境影响,本文拟通过覆盖遮荫的方式人为改变茶树树冠微域环境,以探明树冠微域环境对茶树碳氮代谢等的影响。【方法】采用田间小区试验,通过在茶树树冠面上分别覆盖光热透过性能不同的三种遮荫材料,人为改变茶树树冠面的微域环境,以不覆盖为对照,比较不同树冠微域环境条件下树冠面空气温度、空气湿度、光照等环境因子的变化及光合速率等的差异,并通过氨基酸组分分析及高效液相色谱等方法对不同季节茶树新梢中碳氮初级代谢产物进行分析,以比较树冠微域环境变化对茶树碳氮代谢及茶鲜叶品质等的影响。【结果】茶树树冠面经三种光热透过性能不同的遮阳网在蓬面直接覆盖后,茶树新梢的生长小环境及碳氮代谢均发生了变化: 1）树冠面的光照强度、空气温度及叶片温度均得到了不同程度的降低,空气相对湿度得到了不同程度的提高。其中覆盖隔热网的降温效果最好,降温幅度最高可达3.1℃;覆盖银色网在早晚有较好的降温效果,降温幅度可达1.6℃,但在12时、14时和16时未有明显的降温效果。而覆盖黑网后早晨的树冠面空气温度与叶片温度却显著高于其他各处理,且随着外界温度的升高,黑网下的两种温度与不覆盖比表现出了波动现象。2）茶树被覆盖后,其净光合速率表现出显著的降低趋势,其中黑网覆盖处理与不覆盖处理均在中午12点左右出现一个低谷,出现了午睡现象,而银色网与隔热网覆盖处理没有表现出午睡现象;覆盖后茶树叶片胞间CO2浓度较不覆盖表现出升高趋势,其中以隔热网处理为最高。3）在高温强光季节对茶树进行适度遮荫覆盖,能在一定程度上促进茶树氮代谢,减弱茶树碳代谢,改善各季茶树新梢的品质。主要表现为茶新梢的叶绿素含量、氮磷钾等养分含量、游离氨基酸总量显著增加;氨基酸组分如茶氨酸、谷氨酸、天冬氨酸等也均表现出显著增加趋势;茶新梢中总碳含量及茶多酚等碳水化合物含量降低;总碳、C/N、茶多酚含量等显著降低,儿茶素组分降低但儿茶素品质指数增加、苦涩味指数降低;三种茶树微域环境中,隔热网覆盖的树冠环境对茶叶品质提升方面效果最明显。4）与不覆盖相比,茶树新梢产量表现出了降低的趋势。【结论】通过遮荫覆盖等方式调控茶树树冠微域环境会影响茶树碳氮代谢等生理活动、提高茶鲜叶品质,但茶鲜叶的产量表现出降低的趋势。     

向日葵芽苗期离子对复合盐胁迫的响应

研究向日葵耐盐的离子响应机制,可为快速筛选耐盐向日葵品种提供科学依据。本试验以油用向日葵盐敏感品种‘YK18’、中度耐盐品种‘YK06’和耐盐品种‘GF01’为试验材料,研究0 mmol·L~(–1)、50 mmol·L~(–1)、100 mmol·L~(–1)、150 mmol·L~(–1)、200 mmol·L~(–1)和250 mmol·L~(–1)复合盐(NaCl和Na_2SO_4按9∶1摩尔比混合)浓度下的种子萌发和离子在萌发幼苗中积累分布情况,并利用离子流检测技术,动态监测了复合盐胁迫24 h后植株根系的K~+、Na~+、Ca~(2+)等离子的流速流向。结果表明,复合盐胁迫抑制向日葵种子萌发,导致发芽率下降,平均发芽时间延长。盐胁迫后向日葵根系K~+大量外排,流速为‘YK18’‘YK06’‘GF01’;随着盐胁迫浓度升高,根系Na~+流速由内吸转为外排,内吸时‘YK18’速度最大,‘YK06’次之,‘GF01’最小,外排时‘GF01’流速最大,其"排盐"现象明显。复合盐胁迫后,整株的Na~+积累量增加,K~+减少,K~+/Na~+随着盐浓度升高而下降;低盐浓度(150 mmol·L~(–1))下‘GF01’和‘YK06’茎秆中K~+/Na~+低于‘YK18’;高盐胁迫(≥150 mmol·L~(–1))下,‘GF01’整株Na~+积累最少,叶片K~+/Na~+最高。另外,盐胁迫下向日葵幼苗根系Ca~(2+)的吸收速率加快,‘GF01’是‘YK18’的2倍。由此可见,不同耐盐性的油用向日葵植株在盐胁迫下可通过调节Na~+、K~+和Ca~(2+)的吸收与外排来适应盐胁迫环境,耐盐性强的品种具有更强的保K~+能力,并通过区域化Na~+(低盐胁迫)和拒盐机制(高盐胁迫)来提高其对盐胁迫的耐受性,维持植株叶片中合理的K~+/Na~+值。本研究结果可为盐碱地耐盐品种筛选和栽培提供理论依据。     

Higher ROS scavenging ability and plasma membrane H+‐ATPase activity are associated with potassium retention in drought tolerant tea plants

Drought is one of the main limiting factors resulting in the reduction of yield and quality of tea production. Our previous studies indicated that K⁺ retention was a key factor associated with alleviating drought‐induced damage in tea plants. However, the underlying mechanisms are still unclear. In the present study, drought tolerant tea plant (variety Zhongcha108) exhibited higher plasma membrane (PM) H⁺‐ATPase activity and lower negative membrane potential compared with the drought sensitive tea plant (variety Ruanzhiwulong). In addition to superior mesophyll K⁺ retention ability and higher PM H⁺‐ATPase activity, the drought tolerant tea plant exhibited lower accumulation of reactive oxygen species (ROS) than the sensitive one. Moreover, exogenous supply of Na₃VO₄ (plasma membrane H⁺‐ATPase inhibitor) and H₂O₂ (mimicking apoplastic ROS) resulted in a significantly higher K⁺ efflux in the mesophyll of the drought sensitive tea plant than the non‐treated one. Taken together, the higher ROS scavenging ability and plasma membrane H⁺‐ATPase activity were major factors contributing to the higher K⁺ retention in drought tolerant tea plants.     

Screening of Basmati Rice Varieties for their Arsenic Accumulation in Punjab,North-West India

A pot study was conducted to screen different basmati rice varieties for their accumulation of arsenic (As). Different amounts of arsenic (0–800 µg/L) were applied through irrigation water to four basmati rice varieties (Pusa basmati-1121, Pusa Punjab basmati-1509, Punjab basmati-2, and Punjab basmati-3). Highest arsenic concentration was found in the grains of Punjab basmati-3 and lowest in the grains of Pusa Punjab basmati-1509. In all varieties, grain As concentration ranged from 0.038 to 0.288 mg/kg, which was within the permissible limit of 1.0 mg/kg in rice grain recommended by World Health Organization (WHO). In husk, highest As concentration was found in Pusa basmati-1121 and lowest in Punjab basmati-2. Among the four varieties, highest content of As was accumulated in roots and straw of Pusa Punjab basmati-1509, whereas least was accumulated in Punjab basmati-2. The distribution of arsenic among plant parts was found in the order: roots > straw > husk > grain. The mean arsenic concentrations in grain, husk, straw, and root of basmati rice varieties increased with increasing concentration of arsenic in irrigation water. Highest grain yield was obtained in Pusa Punjab basmati-1509 variety due to lesser accumulation of arsenic compared with other varieties. Rice yield, plant height, root weight, straw weight, test weight, effective tiller, and filled grain per panicle decreased with increase in arsenic concentration in irrigated water.     

Effect of zinc application on the dry matter yield uptake and distribution of zinc and other micronutrients in cocoa (Theobroma cacao. L.)

Abstract

The effects of application of zinc fertilizer on dry matter yield, uptake and distribution of zinc and other nutrients by Amazon and Amelonado cocoa cultivars grown in a soil of low zinc content in the greenhouse were investigated.

There was a differential response to zinc fertilization by the two cocoa cultivars. Maximum dry matter yields of Amazon and Amelonado were attained with 10 ppm Zn and 50 ppm Zn, respectively. Under similar experimental conditions Amelonado seedlings expressed zinc deficiency symptoms whereas Amazon did not.

Zinc concentrations in the leaves, stem and roots of both cuitivars did not give a good index of the zinc status of the crops. This was because of the existence of the “Piper‐Steenbjerg”; effect in that nil zinc rates often gave higher leaf concentration of the zinc than next higher rate. In general, the relative content of zinc followed the pattern; leaves > roots > stem with the Amazon cultivar containing more zinc than the Amelonado.

The distribution of absorbed Cu in the leaves, stem and roots did not differ in both varieties. Whereas Fe uptake was mostly concentrated in the roots, Mn absorbed was largely concentrated in the leaves of both varieties and only Mn uptake in the leaves of Amazon consistently increased with Zn application.

The differences in the uptake and distribution of nutrients between the two cocoa cultivars was attributed to differences in their ability to extract nutrients from the soil and in their requirements for metabolic processes.     

Spacing and Plant Density in the Yield Components,Nutritional Status,and Soil Fertility of Guarana Varieties Grown in Humid Tropical Amazon

In agriculture there is a tendency to reduce spacing between plant rows, both for perennial and annual plants. Yield gains have been associated with the use of this technique. However, in the case of perennial plants, this technique was found to reduce productivity in older orchards because of the greater competition between plants caused by the increased volume of the crown and root system, resulting in lower photosynthetic efficiency, increased infestation with fungal diseases, and greater competition in nutrient uptake. In addition to yield, efficient management should consider soil fertility, nutritional status, and the growth of the guarana variety. The present study aimed to assess the effects of spacing and plant density on grain yield, soil fertility, and nutritional status of two guarana varieties (BRS Amazonas and BRS Maués). The plant density studied were 625 (4 m × 4 m), 833 (4 m × 3 m), 1,111 (3 m × 3 m), 1,666 (3 m × 2 m), 2,500 (2 m × 2 m), and 5,000 (2 m × 1 m) plants per hectare distributed in randomized block design with three replicates. The high plant density has significantly increased grain yield in the guarana varieties, with changes in launch number, trunk diameter, and crown diameter. Regarding macronutrients, in the average of the varieties, the mean foliar concentration had the following sequence: nitrogen (N) > potassium (K) > calcium (Ca) > phosphorus (P) > sulfur (S) > magnesium (Mg), whereas for micronutrients it was manganese (Mn) > iron (Fe) > boron (B) > zinc (Zn) > copper (Cu). The differences in the foliar concentrations of the varieties and in soil fertility are important tools for the selection of materials with better capacity of uptake and/or translocation of nutrients, resulting in greater grain yield.     

Effects of arbuscular mycorrhizal inoculation on cadmium accumulation by different tobacco (Nicotiana tabacum L.) types

The effect of arbuscular mycorrhiza (AM) on cadmium (Cd) uptake by tobacco (Nicotiana tabacum L.) was studied in a pot experiment. Three commercial varieties, Basma BEK, K326 and TN90, representing three distinct tobacco types, were each grown in a different soil with nutritional conditions matching as closely as possible their requirements for field production. Cd concentrations in these soils were within the background range. Each variety was either non-mycorrhizal or inoculated with one of five AM fungal isolates. Cd concentration in leaves was decreased by inoculation with selected isolates in the K326 and TN90 variety grown in acidic soils. In contrast, it was increased by inoculation with most isolates in the Basma BEK variety grown in a basic soil with low Cd availability. Besides, plants of all three varieties had significantly higher leaf concentrations of phosphorus and nitrogen in some inoculated treatments. The percentage of root colonisation was mostly low in the inoculated treatments. In the Basma BEK and TN90 variety, the tested AM fungal isolates differed in their ability to colonise roots, but no correlation was found between the root colonisation of an isolate and its effects on the Cd concentrations in tobacco leaves. One isolate influenced most pronouncedly Cd concentrations and improved mineral nutrition in all the three combinations of variety and soil despite its low colonisation levels. AM symbiosis probably affected Cd uptake of tobacco by indirect mechanisms such as stimulation of root growth or mycorrhizal plant mediated changes in chemical or biological soil properties.     

Zinc nutrition affects alfalfa responses to water stress and excessive moisture

The interactive effect of applied zinc (Zn) and soil moisture on early vegetative growth of three alfalfa (lucerne) (Medicago sativa L.) varieties was investigated in a sand‐culture pot experiment to test whether there is link between Zn nutrition and soil moisture stress or excessive moisture tolerance in alfalfa plants. Three varieties (Sceptre, Pioneer L 69, and Hunterfield) with differential Zn efficiency (ability of a variety to grow and yield well in a Zn deficient soil is called a Zn‐efficient variety) were grown at two Zn levels (low Zn supply: 0.05 mg Zn kg^‐1 of soil, adequate Zn supply: 2.0 mg Zn kg^‐1 of soil) and three levels of soil moisture (soil moisture stress: 3% soil moisture on soil dry weight basis; adequate soil moisture: 12% soil moisture on soil dry weight basis; excessive soil moisture: 18% soil moisture on soil dry weight basis) in a Zn deficient (DTPA Zn: 0.06 mg kg^‐1 soil) siliceous sand. Zinc treatments were applied at planting, while soil moisture treatments were applied three weeks after planting and continued for two weeks. Plants were grown in pots under controlled temperature conditions (20°C, 12 h day length; 15°C, 12 h night cycle) in a glasshouse. Plants grown at low Zn supply developed Zn deficiency symptoms, and there was a severe solute leakage from the leaves of Zn‐deficient plants. Adequate Zn supply significantly enhanced the leaf area, leaf to stem ratio, biomass production of shoots, and roots, succulence of plants and Zn concentration in leaves. At low Zn supply, soil moisture stress and excessive moisture treatments significantly depressed the shoot dry matter, leaf area and leaf to stem ratio of alfalfa plants, while there was little impact of soil moisture treatments when supplied Zn concentration was high. The detrimental effects of soil moisture stress and excessive soil moisture under low Zn supply were less pronounced in Sceptre, a Zn‐efficient alfalfa variety compared with Hunterfield, a Zn‐inefficient variety. Results suggest that the ability of alfalfa plants to cope with water stress and excessive soil moisture during early vegetative stage was enhanced with adequate Zn nutrition.     

Nutrient indexing of peanut in some selected villages of the Punjab

Abstract

Samples of peanut plants from 5 selected villages of Ludhiana and Kapurthala (Punjab, India) were analysed for P, K, Ca, Mg, S, Zn, Cu, Mn and B. The dominant nutrient deficiencies were of B > K > S > Zn> P >Mn> Cu. Potassium and magnesium seem to interact antagonistically for their absorption. The inherent low status of nutrients in these soils appears to be the reason for their wide‐spread deficiency and consequent low yield of peanut crop.     

Arsenic Accumulation in Rice (Oryza sativa L.) Varieties of Bangladesh: A Glass House Study

A glass house study was conducted to investigate the accumulation of arsenic in tissues of five widely cultivated rice (Oryza sativa L.) varieties of Bangladesh namely BRRI dhan 28, BRRI dhan 29, BRRI dhan 35, BRRI dhan 36, BRRI hybrid dhan 1. Arsenic concentrations were measured in straw, husk and brown and polish rice grain to see the differential accumulation of arsenic among the rice varieties. The results showed that the concentrations of arsenic in different parts of all rice varieties increased significantly (p?<?0.05) with the increase of its concentrations in soil. The rice varieties did not showed significant differences in arsenic accumulation in straw, husk, brown and polish grain when the concentrations of arsenic in soil was low. However, at higher concentrations of arsenic in soil, different rice varieties showed significant differences in the accumulations of arsenic in straw, husk and grain. Significantly higher concentrations of arsenic in straw and husk of rice were observed in BRRI hybrid dhan 1 compared to those of other verities. The BRRI dhan 28 and 35 concentrated significantly higher amount of arsenic in brown and polish rice grain compared to those of other rice varieties. The results imply that arsenic translocation from root to shoot (straw) and husk was higher in hybrid variety compared to those of non-hybrid varieties. Arsenic concentrations in brown and polish rice grain of five rice varieties were found to follow the trend: BRRI dhan 28 > BRRI dhan 35 > BRRI dhan 36 > BRRI dhan 29 > BRRI hybrid dhan 1. The order of arsenic contents in tissues of rice was: straw > husk > brown rice grain > polish rice grain.