长期施肥条件下西南黄壤旱地有效磷对磷盈亏的响应

以贵州黄壤肥力与肥效长期定位试验为平台,探究有效磷(Olsen-P)与土壤累积磷盈亏、磷肥用量的关系,确定西南黄壤旱地最佳磷肥施肥量,通过Mitscherlich方程模拟作物相对产量对土壤Olsen-P的响应关系,明确西南黄壤旱地的农学阈值.结果表明: 施用磷肥可显著提高土壤Olsen-P含量,不同施磷处理间提升幅度主要与磷肥施用量有关;不施磷处理土壤磷素一直处于亏缺状态,施磷处理土壤磷素有盈余,其中全量有机肥配施全量化肥处理(MNPK)作物吸磷量和磷素盈余量最高,同等施磷水平下,与单施化肥处理(NPK)相比,有机肥配施化肥处理(1/4 M +3/4 NPK、1/2 M +1/2 NPK)更能促进作物对磷素的吸收,提高磷素累积利用率.土壤累积磷盈亏与土壤Olsen-P增量呈显著直线相关关系(P<0.05),土壤中磷素每盈余100 kg·hm^-2,MNPK、1/4 M +3/4 NPK、1/2 M +1/2 NPK、NPK处理Olsen-P分别增加16.4、13.0、21.4、5.6 mg·kg^-1,有机肥与化肥配施能有效增加土壤Olsen-P含量.西南黄壤旱地Olsen-P的农学阈值为22.4 mg·kg^-1;土壤每年磷盈亏和Olsen-P含量与磷肥施用量呈极显著正相关关系(P<0.01),磷肥用量(纯P)为每年33.3 kg·hm^-2时,土壤磷盈亏呈持平状态,Olsen-P农学阈值对应的施肥量(纯P)为每年45.9 kg·hm^-2.西南黄壤旱地Olsen-P含量主要与施磷水平有关,当年施磷量为45.9 kg·hm^-2时可获得最佳的作物产量,磷肥利用率高;当年施磷量高于45.9 kg·hm^-2时,作物产量对磷肥用量无响应,大量磷素累积在土壤中,增加了磷素的环境流失风险.西南黄壤旱地长期施用有机肥处理单位累积磷盈余量提升土壤Olsen-P的速率大于单施化学磷肥处理.     

硫氮配施对持绿型小麦氮素运转及叶片衰老的影响

以持绿型小麦品种‘豫麦66号’、‘潍麦8号’及非持绿型品种‘小偃6号’为材料,采用以氮肥为主区硫肥为副区的田间裂区试验,研究了2个施氮水平[纯氮120kg/hm2(N120)、220kg/hm2(N220)]和3个施硫水平[纯硫0kg/hm2(S0)、20kg/hm2(S20)、60kg/hm2(S60)]下植株各部位的含氮量、叶片干鲜重及叶片叶绿素含量的变化,探讨硫氮配施对不同类型小麦氮吸收及衰老的影响。结果表明:在相同处理下,持绿型小麦植株的总含氮量、氮素转运量、叶绿素含量、叶片含水量及穗粒数和千粒重均高于非持绿型小麦。N120处理条件下,不同硫肥处理时持绿型小麦与非持绿型小麦变化趋势相同,开花期茎和叶含氮量及叶绿素含量在S60处理下均低于其他2个硫肥处理,生育后期叶片含水量下降幅度也明显高于其他处理;在N220处理条件下,3个品种开花期叶含氮量、收获期总氮累积量、氮收获指数、叶绿素含量及叶片含水量在S60处理下均高于其他2个处理,其中非持绿型小麦在高硫处理条件下灌浆期的叶绿素含量的增长率明显高于持绿型小麦,而灌浆中后期叶片含水量的下降幅度则明显低于持绿型小麦。研究发现,施用硫肥在氮肥不足时会对小麦植株氮素的吸收利用及叶片衰老等方面产生负面影响,但在氮肥充足时却在氮素的吸收利用、延缓叶片衰老及最终籽粒产量和总生物量等方面表现出正面效应;本实验条件下,220kg/hm2左右施氮量和60kg/hm2左右施硫量有利于各品种小麦生长发育和产量提高;高N和高S水平对于延缓小麦的衰老而言,非持绿性小麦比持绿型小麦更明显。     

分蘖期冷水胁迫下施氮量对寒地粳稻氮代谢和籽粒蛋白质含量的影响

以寒地粳稻东农428、龙稻7和松粳10为试验材料,研究分蘖期冷水胁迫下不同施氮量处理对功能叶片氮代谢关键酶活性、籽粒蛋白质含量以及产量的影响,并探讨功能叶片氮代谢关键酶活性与籽粒蛋白质含量以及产量的关系。研究结果表明,分蘖期冷水胁迫使NR,GS活性及籽粒蛋白质含量升高,GOGAT和GDH活性下降。分蘖期冷水胁迫下,增加施氮量使各品种功能叶酶活性及籽粒蛋白质含量均缓慢升高,其中NR、GS和GOGAT活性在N150处理下最高,GDH活性和籽粒蛋白质含量在N175处理下最高,可知,高施氮量不利于寒地粳稻抗冷。不同品种在冷水胁迫下酶活性表现不一,其中耐冷型品种东农428在各处理下氮代谢关键酶保持较高生理活性,龙稻7次之,松粳10最弱。分蘖期冷水胁迫下,纯氮施用量为100 kg/hm2,其产量表现最佳,3个品种表现一致。     

氮磷肥配施对苦荞根系生理生态及产量的影响

以苦荞品种‘迪庆’为材料,在盆栽试验条件下,研究了氮(纯氮用量分别为0g/kg、0.1g/kg、0.2g/kg)、磷(P2O5用量分别为0.1g/kg和0.2g/kg)配施对苦荞根系生长、生理指标及其产量的影响,旨在为黄土高原苦荞高产优质栽培提供理论依据。结果表明:(1)在相同施磷量条件下,苦荞幼苗的株高、茎粗、茎叶干重、主根长、根表面积、根系体积、根系直径、根系干重以及壮苗指数等均随施氮量的增加而呈先升后降的趋势,但根冠比随施氮量的增加而呈先降后升的趋势;叶片叶绿素含量以及根系活力、酸性磷酸酶(Apase)活性、可溶性蛋白含量和植株氮积累量随施氮量的增加呈抛物线变化趋势,根系硝酸还原酶(NR)活性和植株氮含量随施氮量的增加而增加;而根系可溶性糖含量、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、丙二醛(MDA)含量和游离脯氨酸含量等指标均随施氮量的增加而呈先降后升的趋势,0.1g/kg施氮处理各指标均显著低于其他处理;成熟期单株粒重、百粒重随施氮量的增加呈先升后降的趋势,0.1g/kg施氮处理各指标均显著高于其他处理。(2)在相同施氮量条件下,随着施磷量的增加,苦荞根系酸性磷酸酶(Apase)活性、SOD活性、POD活性、MDA含量、可溶性糖含量、可溶性蛋白以及游离脯氨酸含量等指标均降低,其余各指标则呈增加趋势。(3)无论施磷量条件如何,0.1g/kg的施氮处理下苦荞产量最高,与其他施氮处理相比,在低磷和高磷处理下的增产幅度分别为7.04%~37.40%和14.73%~68.26%;在施氮量一定的情况下,高磷处理比低磷处理增产15.96%~42.00%。(4)在该试验条件下,适当的氮磷肥配施表现出了明显的正加和效应,但过量施肥也有可能导致增产幅度下降,中氮高磷(施纯N量0.1g/kg,施P2O5量0.2g/kg)配施效果最优。     

不同施肥灌水处理对不同小麦品种产量和品质的影响

在小麦生育期间降水47.9 mm的条件下,以3个小麦品种为试验材料,采用四因素三水平正交设计,研究了不同灌水和施肥处理对不同小麦品种子粒产量、蛋白质含量和沉降值的影响。结果表明,全生育期施氮量300 kg/hm2和225 kg/hm2的处理子粒产量和蛋白质含量差异不显著,但均显著高于150kg/hm2的处理。在中产条件下氮肥底施和追施比例以7∶3时产量最高。春季灌4水产量显著高于灌2水的处理,但与灌3水差异不显著,子粒蛋白质含量以灌2水时最高。供试品种中以京冬8号的产量、千粒重、容重最高,CA0206和核优1的蛋白质含量差异不显著,但均显著高于京冬8号。CA0206的沉降值显著高于另两个品种。以产量、品质和经济效益综合考虑,在本试验条件下,以春季灌3水、施氮量225 kg/hm2、底施和追施比例为7∶3的处理为宜,与超高产条件下氮素底施和追施比例5∶5的结果有明显的差异。     

旱地小麦休闲期覆盖增磷对籽粒蛋白质积累的影响

为探索旱地小麦休闲期覆盖保水配施磷肥高产、优质的技术途径,在山西农业大学闻喜试验基地采用大田试验研究了休闲期覆盖或不覆盖条件下低(75 kg/hm2)、中(112.5 kg/hm2)、高(150 kg/hm2)施磷水平对土壤水分、籽粒蛋白质形成的影响及其生理机制。结果表明:休闲期覆盖后,播种期0-100 cm土壤蓄水量显著提高,达39-42 mm,而开花期60-100 cm土层降低。覆盖后,花后旗叶和籽粒GS和GOGAT活性提高,籽粒游离氨基酸和灌浆后期GMP含量提高,籽粒蛋白质及其组分含量、谷/醇均提高。增加施磷量,开花期20-60 cm、80-100 cm土层蓄水量降低,而花后旗叶和籽粒GS活性提高,且覆盖条件下花后0-15 d、20 d旗叶GOGAT活性,花后5 d、15 d、25-30 d籽粒GOGAT活性,籽粒游离氨基酸含量、籽粒GMP含量提高,籽粒蛋白质及其组分含量、谷/醇、蛋白质产量显著提高,产量提高940-1452 kg/hm2。此外,休闲期覆盖配施磷肥条件下,开花期深层土壤水分与旗叶GS和GOGAT活性密切相关,旗叶和籽粒GS和GOGAT活性均与游离氨基酸含量、谷/醇、蛋白质产量关系密切。总之,旱地小麦休闲期覆盖有利于提高底墒,且配合施磷量150 kg/hm2可促进根系吸收深层土壤水分,提高产量的同时也提高了籽粒蛋白质含量、GMP含量和谷/醇。     

施N对不同水稻品种N肥利用率及根际硝化作用和硝化微生物的影响

发生在水稻根际的硝化作用对水稻的氮素（N）营养受到人们越来越大的关注。在田间条件下研究了不同N效率粳稻品种（4007、武运粳7号和Elio）在无肥（0kgN/hm^2）、中肥（180kgN/hm^2）和高肥（300kgN/hm^2）水平下籽粒产量、吸N量、N肥利用率、根际土壤铵态氮（NH4^＋-N）和硝态氮（NO3^--N）含量、硝化强度和氨氧化细菌（AOB）数量。结果表明不同水稻品种的籽粒产量在3个N处理中差异极显著,4007在中肥处理中获得最高产量11117kg/hm^2,而Eilo在所有处理中籽粒产量均最低。各品种地上部吸N量随施N量增加而增加,但各品种之间差异不显著。不同水稻品种N肥利用率差异显著,4007显著高于武运粳7号和Elio。本试验根据不同品种水稻在不施N肥水平下的籽粒产量与N肥利用率的大小,将3个品种分为N肥高效敏感型（4007）、N肥高效不敏感型（武运粳7号）和N肥低效不敏感型（Elio）。在水稻中后期干湿交替的水分管理条件下,无肥和中肥区的水稻根际土壤以NO3^--N为主;而在高肥区则以NH4^＋-N为主。随着施N量增加,水稻根际土壤铵、硝态N含量也随之增加。NH4^＋-N含量在无肥、中肥和高肥水平下分别为0.88、0.94mg/kg和13.5mg/kg,而NO3^--N含量分别为1.61、1.73mg/kg和2.33mg/kg。不同水稻品种根际土壤硝化强度之间差异极显著,在3个施N水平下均表现为4007〉武运粳7号〉Elio。其平均值分别为6.94、5.46μg/（kg·h）和2.42μg/（kg·h）。在3个施N水平下,Elio根际土壤AOB数量均显著低于4007和武运粳7号。4007根际土壤AOB数量在高肥水平下达最大值2.02×106个/g土,而最小值为中肥水平下Elio的根际土壤（1.89×105个/g土）。相关性分析表明,水稻根际土壤硝化强度在无肥、中肥和高肥条件下与产量呈极显著正相关关系（r=0.799,0.877,0.934）,而且在中肥条件下与水稻N肥利用率显著相关（r=0.735）。水稻根际土壤AOB数量分别和硝化强度以及水稻籽粒产量呈极显著正相关关系。试验结果表明,水稻根际的硝化作用较大程度上决定着水稻籽粒产量或水稻N肥利用率。     

黄淮海平原玉米施氮量对后茬小麦土壤剖面硝态氮和产量的影响

在冬小麦-夏玉米一年两熟模式下,玉米品种“郑单958”（植株密度9株/m^2）和小麦品种“93-9”（基本苗704株/m^2）,冬小麦基施144kg N/hm^2,研究了玉米5个施N量（0、90、180、270和360kg/hm^2）对后茬小麦期间土壤剖面硝态氮含量、无机氮总量,以及小麦氮素吸收利用和产量的影响.结果表明：（1）与不施氮相比,玉米施氮显著增加小麦季0～200cm土壤硝态氮含量;自拔节起,0～40cm、0～130cm和0～200cm硝态氮含量均随施氮量增加而递增,在硝态氮含量较高的小区增幅也大.（2）轮作一周期后,不施氮和施氮360kg/hm^2显著影响0～130cm和0～200cm无机氮总量,但在90～270 kg/hm^2之间,施氮量的影响不明显.（3）施氮小于180kg/hm^2时,成熟期小麦植株氮素和籽粒氮素积累量、氮肥利用率均随施氮量增加而递增,但不明显.（4）与不施氮相比,施氮90kg/hm^2的小麦产量和麦玉轮作总产均增加但不明显,施氮180 kg/hm^2均显著增加,施氮270kg/hm^2与180kg/hm^2无明显差异.本试验条件下,夏玉米施氮90～180 kg/hm^2是适宜的.     

延安市日光温室蔬菜施肥现状与环境效应

调查分析延安市日光温室蔬菜目前的施肥现状和存在问题,结果表明蔬菜主要施肥问题是偏施氮磷肥,而且用量超过蔬菜的需肥量,忽视钾肥和微量元素的施用。过量施肥造成土壤NO3^-—N累积和地下水NO3^-—N含量超标,地下水NO3^-—N含量达142mg／L。根据西红柿和黄瓜的需肥要求,提出了黄瓜和西红柿合理的N、P、K肥和有机肥用量。日光温室黄瓜产量150000kg／hm^2的施用量为N750—840kg／hm^2,P2O5 450—540kg／hm^2,K2O 450—750kg/hm^2,有机肥60-80t/hm^2较为合理。日光温室西红柿180 000kg/hm^2产量的施用量为N810-960kg/hm^2,P2O5 420-510kg／hm^2,K2O 540-690kg／hm^2,有机肥50-80t/hm^2较为合理。分析了施肥对土壤环境和地下水NO3^-—N含量的影响,并提出了日光温室蔬菜施肥的改进措施。     

外源甜菜碱对盐胁迫下颠茄生理特性及托品烷类生物碱含量的影响

以颠茄(Atropa belladonna L.)幼苗为材料,通过人工模拟盐胁迫条件,探讨在100 mmol/L盐胁迫下喷施不同浓度(20 mmol/L和40 mmol/L)的甜菜碱(GB)溶液对颠茄幼苗生理特性及托品烷类生物碱含量的影响。结果显示,外源甜菜碱增强了颠茄叶片的光合作用,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性均有不同程度的提高;丙二醛(MDA)含量显著下降,硝态氮、可溶性蛋白、游离氨基酸含量及硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、谷氨酸脱氢酶(GDH)活性显著升高。颠茄次生代谢途径中的前体氨基酸(鸟氨酸和精氨酸)的含量以及托品烷类生物碱(莨菪碱和东莨菪碱)的含量也明显升高。研究结果表明100 mmol/L盐胁迫处理对颠茄的生长产生了抑制作用,而20 mmol/L甜菜碱处理能较好地缓解这种伤害。     

Deoxyribonucleic Acid, Ribonucleic Acid, Protein and Uncombined Amino Acid Content of Legume Seeds During Embryogeny

The nucleic acid, protein and uncombined amino acid contentof seeds of soya-bean (Glycine max L. Merr.), garden pea (Pisumsativum L.), kidney bean (Phaseolus vulgaris L.) and peanut(Arachis hypogaea L.) were measured at various times duringseed formation in an effort to understand why the soya-beanhas nearly twice as much protein as the other legume seeds.In all these species the concentration of deoxyribonucleic acid,ribonucleic acid and uncombined amino acids decreased duringseed formation. The protein level of kidney bean was relativelyconstant during development whereas the protein levels of pea,peanut and soya-bean increased during development. The proteincontent of the soya-bean increased throughout development whereasthe protein increase in peanut took place early and that inpea took place later in development. The ratio of protein toribonucleic acid was highest in peanut, less in soya-bean, andlowest in pea and kidney bean. Similarly, the ratio of proteinto deoxyribonucleic acid was higher in kidney bean than in soya-bean.Soya-beans had a lower amino acid content than any of the otherseeds at all stages of development. These results indicate thatneither total deoxyribonucleic acid, ribonucleic acid nor uncombinedamino acid content is responsible for the higher protein contentof soya-beans.     

施氮水平对小麦籽粒发育过程中氨基酸含量的影响

施氮能提高小麦籽粒蛋白质氨基酸的含量,并与施氮水平呈正相关;但对普通小麦必需氨基酸与蛋白质氨基酸的比值没有影响,而硬粒小麦4286随施氮水平的提高,该比值下降。在开花后32d以前,籽粒发育过程中游离氨基酸与施氮水平呈正相关,以后,籽粒中游离氨基酸趋于相近,表明施氮增加了游离氨基酸的库源,不同基因型小麦对施氮水平的反应不同,在同等施氮水平和栽培条件下,籽粒中蛋白质氨基酸和游离氨基酸含量为硬粒小麦4286＞小偃6号＞小偃107,不同施氮水平下,籽粒中氨基酸含量为高氮＞中氮＞低氮。     

Oligosaccharides in Five Different Vicia faba L. Cultivars

The oligosaccharide composition in seeds of some bean cultivars (two of Vicia faba L. and three of V. faba minor) have been examined. The sugars were isolated by solvent extraction and the concentrated extracts were analysed by PC and HPLC analyses. Characterization was also performed by thin-layer chromatography, enzymatic hydrolysis assays, GC determination of alditol acetate derivatives obtained after complete acid hydrolysis and FAB-MS of individual sucrose - galactosides. Although sucrose, raffinose, stachyose and verbascose were always identified, great differences in the total sugar content were found among the five cultivars. Sucrose and verbascose were the major components. Their contents were highest in the Muchamiel cv. (2.30 and 3.05 g/100g of dry bean, respectively). The selection of cultivars is the best way to improve the V. faba quality     

Age-stage,two-sex life table of the tomato looper,Chrysodeixis chalcites (Lepidoptera: Noctuidae), on different bean cultivars

The tomato looper, Chrysodeixis chalcites (Esper), is one of the polyphagous pests of several economically crops worldwide. Two-sex life table parameters of C. chalcites reared on eight bean cultivars including white kidney bean (cultivars Daneshkadeh and Dehghan), red kidney bean (cultivars Goli and Naz), common bean (cultivars Khomein, Talash and Sadra) and cowpea (cultivar Mashhad) were studied under laboratory conditions (25 ± 1 °C, 65 ± 5 % RH, a 16:8-h light–dark photoperiod). The shortest larval period of C. chalcites was 14.15 days on common bean Sadra. The longest and shortest development time of total preadult was on white kidney bean Daneshkadeh and common bean Sadra (25.77 and 23.42 days, respectively). The highest total fecundity was on common bean Sadra (674.4 eggs), and the lowest was observed on white kidney bean Daneshkadeh (136.7 eggs). The intrinsic rate of increase (r _m ) ranged from 0.0976 to 0.1599 female/female/day, which was lowest on white kidney bean Daneshkadeh and highest on common bean Sadra. The net reproductive rate (R ₀) was highest on common bean Sadra (265.82 offspring) and lowest on white kidney bean Daneshkadeh (46.88 offspring). The results revealed that the cultivar Daneshkadeh was unsuitable host to C. chalcites in comparison to the other cultivars tested.     

氮磷钾硫对冬小麦产量及加工品质的调节效应

试验在中国农业科学院作物科学研究所试验基地进行,以强筋小麦品种为试验材料,研究不同氮磷钾硫肥料处理对小麦产量和品质的影响.结果表明,在高产的条件下以120kg/hm2施氮的处理,产量、千粒重和容重最高,过度施氮使产量、千粒重和容重呈逐渐降低的趋势,子粒硬度随施氮量增加而提高.蛋白质含量、湿面筋含量、形成时间和稳定时间均有随施氮量增加而提高的趋势,增加施氮量显著增加了面包体积.蛋白质含量、湿面筋含量和稳定时间有随施钾量增加而提高的趋势.施磷和硫处理对产量和品质的影响不显著.     

Levels of copper and zinc in diets for growing and finishing pigs can be reduced without detrimental effects on production and mineral status

One hundred and sixty pigs were used to evaluate dietary copper (Cu) and zinc (Zn) supplementation on performance, fecal mineral levels, body mineral status and carcass and meat quality. Diets differed in mineral form (MF) (Cu and Zn in the form of proteinate amino acid chelate (organic) or sulfate (inorganic)) and inclusion level (IL) (27 mg/kg of total Cu and 65 mg/kg of total Zn ('low') or 156 mg/kg of total Cu and 170 mg/kg of total Zn ('high')) according to a 2 × 2 factorial arrangement of treatments. Pigs were used from 25 to 107 kg body weight (BW) and fed their respective diets ad libitum. Blood and fecal samples were collected on days 14 and 77 of the experiment. Blood was analyzed for concentration of Cu and Zn, hemoglobin (Hb), Cu content of red blood cells (RBC Cu) and alkaline phosphatase (ALP) and feces for Cu and Zn concentration. Hot carcass weight (HCW) and backfat depth were measured at slaughter and indices of meat quality were assessed on a section of longissimus thoracis. Liver, kidney and bone samples were collected immediately after slaughter and liver and kidney were tested for Cu and Zn content, while bone was only tested for Zn. Over the entire experimental period (25 to 107 kg BW) no significant treatment differences in average daily gain (ADG) or average daily feed intake (ADFI) occurred; however, feed conversion ratio (FCR) was improved by the inclusion of proteinate amino acid chelate (P = 0.012). Copper and Zn concentrations in feces were in direct proportion to the IL in the diet. Blood mineral levels were within normal physiological ranges in all treatments and tissue Cu and Zn concentrations increased with dietary IL (P < 0.05). Results indicate that Cu and Zn fecal concentrations were reduced by approximately 6-fold for Cu and by 2.5-fold for Zn by feeding 27 mg/kg Cu and 65 mg/kg Zn, in either the proteinate amino acid chelate or the sulfate form, compared with a diet containing 156 mg/kg Cu and 170 mg/kg Zn. This decrease in total dietary Cu and Zn did not reduce performance or mineral status of pigs.     

Compositional studies and biological activities of some mash bean (Vigna mungo (L.) Hepper) cultivars commonly consumed in Pakistan

Background

In recent years, the desire to adopt a healthy diet has drawn attention to legume seeds and food products derived from them. Mash bean is an important legume crop used in Pakistan however a systematic mapping of the chemical composition of mash bean seeds is lacking. Therefore seeds of four mash bean (Vigna mungo (L.) Hepper, family Leguminoseae) cultivars (NARC-Mash-1, NARC-Mash-2, NARC-Mash-3, NARC-Mash-97) commonly consumed in Pakistan have been analyzed for their chemical composition, antioxidant potential and biological activities like inhibition of formation of advanced glycation end products (AGE) activity and tyrosinase inhibition activity.

Results

The investigated cultivars varied in terms of biochemical composition to various extents. Mineral composition indicated potassium and zinc in highest and lowest amounts respectively, in all cultivars. The amino acid profile in protein of these cultivars suggested cysteine is present in lowest quantity in all cultivars while fatty acid distribution pattern indicated unsaturated fatty acids as major fatty acids in all cultivars. All cultivars were found to be rich source of tocopherols and sterols. Fourier transform infrared spectroscopy (FTIR) fingerprints of seed flour and extracts indicated major functional groups such as polysaccharides, lipids, amides, amines and amino acids. Results indicated that all investigated cultivars possessed appreciable antioxidant potential.

Conclusions

All cultivars are rich source of protein and possess sufficient content of dietary fiber, a balanced amino acid profile, low saturated fatty acids and antioxidant capacity that rationalizes many traditional uses of seeds of this crop besides its nutritional importance. The collected data will be useful for academic and corporate researchers, nutritionists and clinical dieticians as well as consumers. If proper attention is paid, it may become an important export commodity and may fetch considerable foreign exchange for Pakistan.     

Effects of storage temperature on the contents of sugars and free amino acids in tubers from different potato cultivars and acrylamide in chips

To clarify the effects of storage temperature on potato components and acrylamide in chips, tubers from five cultivars were stored at various temperatures (2, 6, 8, 10, and 18 degrees C) for 18 weeks, and the contents of sugars, free amino acids in tubers, and acrylamide in chips after frying were analyzed. At temperatures lower than 8 degrees C, the contents of reducing sugars increased markedly in all cultivars, with similar increases in the acrylamide level and dark brown chip color. Free amino acids showed little change at the storage temperatures tested and varied within certain ranges characteristic of each cultivar. The contents of reducing sugars correlated well with the acrylamide level when the fructose/asparagine molar ratio in the tubers was <2. When the fructose/asparagine ratio was >2 by low-temperature storage, the asparagine content, rather than the reducing sugar content, was found to be the limiting factor for acrylamide formation.     

不同磷水平下小麦-蚕豆间作根系形态的变化及其与内源激素的关系

采用水培方法,研究了不同磷水平下小麦-蚕豆间作体系根系形态变化及其与内源激素的相关关系。结果表明: 与单作小麦相比,在低磷(1/2P)水平下,小麦-蚕豆间作能显著增加小麦的根长,显著减少小麦根系的平均直径,显著增加根系的表面积;在常规磷(P)水平下,间作能显著降低小麦根系的平均直径,有增加小麦根长和根表面积的趋势;与单作蚕豆相比,间作能明显促进蚕豆根系的增长,同时增加蚕豆根表面积。在1/2P水平下,间作能显著提高小麦和蚕豆根系中的生长素(IAA)、脱落酸(ABA)、水杨酸(SA)和茉莉酸(JA)含量;在P水平下,间作能显著提高小麦根系中的IAA、ABA和JA含量,单、间作小麦根系中的SA含量没有显著差异,间作显著增加了蚕豆根系中ABA和SA含量,单、间作蚕豆根系中的IAA和JA含量无显著差异。单作条件下,小麦和蚕豆根系中的内源激素(IAA、ABA、SA和JA)含量与其根系形态(根长、根平均直径和根表面积)无显著相关性;间作条件下,小麦和蚕豆根系中的IAA含量与根长和根表面积之间存在明显的正相关关系。由此可见,小麦-蚕豆间作能够诱导小麦和蚕豆根系IAA的增加。这种变化可能是驱动间作系统根系形态变化的重要因子。     

耕作方式及施氮量对砂姜黑土区小麦氮代谢及籽粒产量和蛋白质含量的影响

为明确砂姜黑土区小麦(Triticum aestivum)产量和品质形成的耕作方式及施氮量最优组合, 在大田试验条件下, 以深松、旋耕和常规耕作3种耕作方式为主区, 0、120、225、330 kg·hm^-2 4个施氮量为副区, 研究了不同耕作方式及施氮量组合对小麦拔节后氮代谢、籽粒产量和蛋白质含量的影响。结果表明, 随着生育期的推进, 叶片谷氨酰胺合成酶活性、游离氨基酸含量和可溶性蛋白含量均呈先升后降的趋势, 深松方式配合中高氮处理的峰值在花后10天, 而常规耕作和旋耕的4个施氮处理以及深松的低氮处理峰值多在开花期。与常规耕作和旋耕相比, 深松耕作显著降低了10-40 cm的土壤容重, 提高了土壤总空隙度和根干质量, 有利于中后期根系氮素吸收。耕作方式和施氮量对籽粒产量和蛋白质含量影响显著, 均以深松方式最高。3种耕作方式下小麦产量和蛋白质含量均随施氮量增加而增加, 籽粒产量以深松方式配合330 kg·hm^-2施氮量最高, 而常规耕作和旋耕方式的产量在施氮量为225 kg·hm^-2时达到最大。3种耕作方式下籽粒蛋白质含量均以施氮225 kg·hm^-2最高。因此, 在砂姜黑土区宜采用深松耕作方式配合适宜的施氮量, 以改善土壤条件, 促进根系氮素吸收, 延长叶片功能期, 达到产量与蛋白品质提升之目的。