富钾植物籽粒苋(Amaranthus spp.)对土壤矿物钾的吸收利用研究

运用土培、石英砂培、有机酸释钾实验及矿物X衍射分析研究了不同基因型籽粒苋(Amaranthusspp.)对土壤矿物钾的吸收利用及其机制。结果表明,籽粒苋能有效地利用土壤和云母(黑云母和金云母)中的钾;籽粒苋品种R104、CX4对钾的吸收量高于一般型品种(CX77);籽粒苋根系能引起云母矿物向蛭石转化;籽粒苋根系分泌物中的草酸比一般有机酸具有更高的释放矿物中钾素的能力。     

籽粒苋不同富钾基因型根际钾营养与根系特性研究

在缺钾土培和水培条件下,研究了籽粒苋不同基因型根际和非根际土壤速效钾、缓效钾和全钾含量的变化,以及根际微生物数量、根系主要分泌物、根系质子分泌量和根系CEC的变化。结果表明,籽粒苋根际土壤速效钾和缓效钾含量明显高于非根际土壤,且在根际形成钾的相对富集区,富钾基因型R104和K12根际钾的富集能力明显高于一般基因型;籽粒苋根际土壤的全钾含量却低于非根际土壤,富钾基因型的降低幅度大于一般基因型。富钾基因型根际微生物数量和根系分泌能力显著高于一般基因型,且根际细菌和真菌数量与主要根系分泌物的分泌量变化基本保持一致。富钾基因型R104和K12根系CEC和H 分泌量高于一般基因型M9和Cr047,而相同基因型内各品种间的变化不显著。     

籽粒苋不同富钾基因型根系分泌物中有机酸和氨基酸的变化特点

采用溶液培养试验研究了籽粒苋(Amaranthus.spp.)不同富钾基因型在不同供钾水平条件下3个不同生长时期内根系分泌物中氨基酸和有机酸的种类及含量变化情况。结果表明,1)籽粒苋根系分泌物中氨基酸和有机酸含量随着供钾水平的升高而降低,且富钾基因型始终大于一般基因型。在低钾胁迫时,根系分泌物中有10种氨基酸和5种有机酸出现,而在供钾正常时则缺少谷氨酸、甘氨酸、苯丙氨酸、草酸和柠檬酸等;酪氨酸、-氨基丁酸和丝氨酸的含量约占氨基酸分泌总量的一半以上;苹果酸含量约占有机酸分泌总量的60%以上。2)籽粒苋生长50d时,一般基因型氨基酸和有机酸的分泌总量较生长40d时迅速降低,而富钾基因型降低速度则相对较为平稳。在3个生长期内,酪氨酸、-氨基丁酸和丝氨酸均为两类基因型根系分泌物中的主要氨基酸种类,苹果酸则是主要的有机酸类型,其在氨基酸和有机酸分泌总量中所占相对比例均随生长期的延长而升高。3)籽粒苋根系分泌物处理后的土壤速效钾含量均高于清水对照处理,富钾基因型在低钾胁迫时的根系分泌物对土壤钾的活化作用明显大于一般基因型。     

富钾绿肥籽粒苋的研究

通过对１１个籽粒苋品种的引种观测、综合主人选定Ｃｒ０７２为较理想的富钾绿肥;模拟试验结果表明生物甸肥的钾素释放与等钾量的化肥有相同的趋势的特点;盆栽试验按时了籽粒苋对土壤缓效钾和矿物钾具有较强的活化、吸收能力。富钾绿肥的开发利用对缓解我国钾肥资源不足将发挥重要作用。     

自生固氮菌对土壤钾的活化作用

以土壤为钾源,通过液培试验研究了5株自生固氮菌(Azotobacter sp.)对土壤钾的活化作用。结果表明,自生固氮菌能分泌大量的氢离子,大幅度降低培养液p H,使氢离子浓度提高40倍以上。自生固氮菌分泌有机酸的种类与数量因菌株不同而异,这些有机酸包括甲酸、乙酸、草酸、丁二酸、柠檬酸、苹果酸和乳酸等。其中,全部供试菌株均能分泌草酸和苹果酸。在自生固氮菌的培养液中,钾浓度显著高于未接种的培养液,但土壤矿物结构钾则显著降低。由于土壤是培养液钾的唯一来源,说明自生固氮菌可促进土壤矿物钾溶解。相关分析表明,土壤矿物结构钾与自生固氮菌的有机酸分泌总量呈显著负相关(r=-0.845*,n=6),与培养液p H呈显著正相关(r=0.702*,n=6),说明自生固氮菌分泌的有机酸和氢离子可能溶解土壤矿物钾。考虑到自生固氮菌的草酸分泌量最大,络合钙、镁、铁、铝的能力最强,且与有机酸分泌总量呈极显著正相关(r=0.990**,n=6),推测草酸的分泌在活化土壤无效钾的过程中起重要作用。接种自生固氮菌显著降低土壤无效钾,活化能力因菌株不同而异,其原因可能与有机酸分泌的数量和种类有关。     

籽粒苋根际土壤及根系分泌物对矿物态钾的活化作用

通过大田和模拟试验等方法 ,研究了籽粒苋根际土壤及根系分泌物对矿物态钾的活化作用 ,研究结果表明 :(1)籽粒苋根际土壤的速效钾含量较非根际土增加了 1.7倍 ,缓效钾 (K)的含量也提高了 5 5 .9% ;(2 )用籽粒苋根际土壤处理后的花岗岩粉末 ,其速效钾和缓效钾含量均较对照有所增加 ,增幅分别为 2 .8%～ 2 4.7%和 15 .7%～ 44 .7% ;用籽粒苋根际土壤处理后的紫色土 ,其速效钾和缓效钾含量较对照分别增加了 18.5 %和 11.1% ;(3 )通过对y值的综合贡献率计算可知 ,不同籽粒苋模拟根系分泌物对花岗岩粉末中矿物态钾的活化能力大小依次为 :草酸 >蔗糖 >核酸 >乳酸 >柠檬酸。     

大豆和小麦对矿物钾的活化作用研究

大豆、春小麦均能有效地活化利用白云母、钾长石中的结构性钾,结构钾释放量为19.53mg kg-1~45.46mg kg-1。春小麦和大豆根系分泌的有机酸主要为草酸、酒石酸和柠檬酸,其次为乳酸、乙酸和苹果酸。草酸溶液酸性较强,络合能力也强,其活化钾的能力最强。苹果酸、酒石酸、柠檬酸、乙酸和乳酸亦可有效地促进白云母和钾长石的分解,但活化土壤钾的能力比较低。低分子量有机酸作用下矿物钾的释放是酸性水解和络合溶解双重作用的结果。草酸、酒石酸、柠檬酸是影响大豆、春小麦吸收利用矿物钾的主要低分子量有机酸。     

富钾绿肥籽粒苋的研究

通过对11个籽粒苋品种的引种观测、综合评价,选定Cr072为较理想的富钾绿肥;模拟试验结果表明生物钾肥的钾素释放与等钾量的化肥有相同的趋势和特点;盆栽试验探明了籽粒苋对土壤缓效钾和矿物钾具有较强的活化、吸收能力.富钾绿肥的开发利用对缓解我国钾肥资源不足将发挥重要作用.     

籽粒苋不同富钾基因型矿质营养元素含量的研究

采用水培试验,研究了在两种供钾水平(K,0.5mmolL-1和5.0mmolL-1)条件下4个不同籽粒苋品种植株体内矿质营养元素的含量及其变化。同时,还在低钾条件下,测定了不同籽粒苋品种根、茎、叶中矿质营养成分的含量和构成情况,结果表明:(1)籽粒苋各品种氮、钾含量随着供钾水平降低而减少,一般基因型氮钾含量降幅大于富钾基因型;在相同供钾水平条件下,富钾基因型的氮钾含量均高于一般基因型,而相同基因型的不同品种间氮钾含量则相近。籽粒苋各品种氮主要分布在根和叶中,其次是茎;磷大量分布在根,其次是叶,再次是茎;钾主要存在于茎中,根和叶次之。(2)籽粒苋钙、镁、硫含量随着供钾水平的升高而降低,富钾基因型镁、硫含量低于一般基因型。籽粒苋不同品种的钙、镁主要分布在叶片中,其次是茎和根;硫在根中的分布最少,叶中最多。(3)不同品种B、Cu、Fe、Mn、Zn等微量元素含量随着供钾水平的降低而升高,灰分含量则降低。富钾基因型B、Fe、Zn及灰分含量都高于一般基因型,而Cu的含量则是一般基因型高于富钾基因型。4个籽粒苋品种的硼、铜主要存在于叶片中,其次是根,茎含量相对前两者要小;铁、锰、锌在根的含量最高,叶片次之,茎最低,根系中铁的含量分别是叶和茎的7倍左右和10倍以上。     

利用~（14）C示踪法研究杉木光合产物分配和杉木根系分泌物

用￣（１４）Ｃ示踪法研究了杉木光合产物的分配和杉木根系的分泌物。结果表明，杉木饲喂￣（１４）ＣＯ２后１天，光合产物大部分滞留在叶中，只有２７．３８％从叶中输送到新梢、主枝、根和侧枝中，标记后３天，光合产物分配率仍以叶为最高，但所占百分比下降，而主枝、新梢、根和侧枝的分配率相应地有了增加，至标记后２２天，光合产物的分配率以新梢为最高，其次为根，叶退居其后。杉木光合产物输送到根部后，可很快转化为分泌物并排出体外，其分泌量在标记后第４天出现峰值，此后￣（１４）Ｃ分泌物量不断下降。杉木根系分泌物中的有机小分子物质，以糖类为最多，其次是有机酸，氨基酸居第三。     

苋菜对钾素吸收和利用上的基因型差异

The kinetics of K^ absorption and the utilization of both applied K and K in a calcareous alluvisol with low available K by different genotypes of grain amaranth(Amaranthus spp.),an ancient pseudo-cereal that produces a large biomass and a rich source of health nutrients and mineral elements,were studied by means of ion depletion technique and pot experiments.Grain amaranth had a high affinity for K^ absorption comparison with corn and cotton.However,there were differences among Amaranthus spp.in Kabsorption and utilization.Some cultivars such as R104,CX-4,Du001,Hy015 and Hr029 which had a higher rate of K absorption and stronger affinity for K^ were typical varieties with high K-use efficiency(KUE).The results showed that high KUE cultivars grew quickly,possessed stronger ability to take up soil slowly available K and Mineral K,and did not respond to K fertilization in the soil with low available K.Correspondingly,grain amaranth cultivars CX-77,Cr024,Vd001,Re003 and Sn003 were relatively low in KUE,Compared with high KUE cultivars,they took up more soil available K and both of their dry matter accumulation and K uptake responded to K applied significalty.     

Multielemental analysis and classification of amaranth seeds according to their botanical origin

The characterization of amaranth seeds (Amaranthus spp.) was developed for Amaranthus hypochondriacus, Amaranthus cruentus, and Amaranthus dubius. The elemental concentrations were determined by inductively coupled plasma optic atomic spectroscopy. Pattern recognition methods were used for the characterization of seed samples: nonsupervised methods included principal components analysis and cluster analysis; supervised methods were linear discriminant analysis and partial least squares discriminant analysis (PLS-DA). Informed are the concentrations of the following elements: Ag, Al, Ba, Ca, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Mo, Na, Ni, P, S, Sr, V, Zn, and Zr. The lowest mineral content was found in A. hypochondriacus, and the highest one was found in A. dubius. For the classification, selected variables for all multivariate methods were Ba, Cr, Li, Mn, Ni, S, and Sr. Nonsupervised methods allowed us to distinguish between the three species of amaranth; however, PLS-DA supervised methods showed the best prediction ability.     

Cesium uptake of field-grown Amaranthus species in Fukushima focusing on Cs concentration in xylem exudate and root distribution

ABSTRACT

Radiocesium (RCs) discharged by the Fukushima Daiichi Nuclear Power Plant (Tokyo Electric Power Co., Inc.) accident has extensively contaminated agricultural land in Fukushima Prefecture and its neighboring areas. Many studies have demonstrated that Cs (RCs and ¹³³Cs) uptake of plants is affected by the exchangeable K (Ex-K) concentration in soil. However, the precise plant–soil interaction in relation to Cs uptake is still unclear. The aim of this study was to investigate Cs uptake of plant in field by focusing on xylem exudate and roots because nutrients in xylem exudate reflect medium (soil) conditions and affect nutrient accumulation in shoots. Two varieties of amaranth, K4 (Amaranthus caudatus L.) and Mexico type (A. hypochondriacus L.), which have different Cs uptake abilities, were grown in four fields and in pots (750 to 3440 Bq kg^?1 of RCs) in Fukushima Prefecture. Cs concentrations in xylem exudate, shoot, and soil; Ex-K concentration in soil; and root distribution in soil were determined. RCs concentration in xylem exudate varied from 0.04 to 164 Bq kg^?1 and ¹³³Cs concentration in xylem exudate ranged from 0.01 to 33.7 μg kg^?1. The Cs concentrations were decreased by the high Ex-K concentration and the large amount of 2:1 type clay minerals in soil. The average of the ratios of Cs concentration in shoot to Cs concentration in xylem exudate for all samples was 127 ± 112 (mean ± standard deviation), although no clear correlation was found between them. The correlations betwee\n RCs and ¹³³Cs concentrations in xylem exudate and shoot were strong in pot and in the field with low Ex-K concentration. Eighty-five percent of the total root length was distributed in the topsoil (0–20 cm soil layer). The positions where roots take up Cs were estimated from the differences in the vertical distribution of RCs and ¹³³Cs concentrations in soil. The estimated Cs uptake ratios of topsoil to total soil layer ranged from 7% to 91% and varied with the concentration and the vertical distribution of Ex-K in soil.     

Extraction and purification of squalene from amaranthus grain.

Grain amaranth has been suggested as an alternative to marine animals as a natural source of squalene. Oil contents, squalene contents, and fatty acid profiles were determined in 11 genotypes of four grain amaranth species. Although the oil contents of grain amaranth were low (from 5.1% in Amaranthus tricolor to 7.7% in Amaranthus cruentus) as compared to other oil-containing grains, high concentrations of squalene were found in total lipids, ranging from 3.6% in Amaranthus hypochondriacus to 6.1% in A. tricolor. The major fatty acids in Amaranthus oil consisted of palmitic acid (19.1-23.4%), oleic acid (18.7-38.9%), and linoleic acid (36.7-55.9%). A high degree of unsaturation was observed in Amaranthus oils, with S/U ratios of 0.26-0.32. A method to isolate and purify the squalene from Amaranthus oil was developed. After the saponification of K112, the squalene content increased from 4.2% in the crude oil to 43.3% in the unsaponifiables by the removal of the saponifiables. The unsaponifiables were fractionated by silica gel column chromatography to get highly purified squalene. The squalene purity in certain fractions was as high as 98%. Combining the fractions rich in squalene gave a 94% squalene concentrate, with a yield of 90%. The structure of squalene in the purified sample was confirmed by comparison of its ultraviolet spectrum with a standard and from its nuclear magnetic resonance spectra.     

麦饭石矿物肥施用效果试验

通过盆栽种植小白菜及后茬作物苋菜,测定其农艺性状、产量及植株中矿质营养成分含量来研究麦饭石矿物肥肥效。结果表明,麦饭石矿物肥对小白菜和苋菜的茎长、根长、鲜重和矿质元素的积累均有显著影响;当矿物肥的施用量在0～0.87 g.kg-1时,随着矿物肥施用量的增加其作用明显增强,当大于0.87 g.kg-1时,其增效减缓。