磷素水平对大豆氮素积累及产量的影响

利用砂培方法和15N示踪技术研究了磷素水平对大豆氮素积累、根瘤固氮和产量的影响。结果表明:大豆植株氮素积累、根瘤固氮和产量均随磷素营养水平的提高而呈单峰曲线变化,营养液磷素浓度31mg/L左右时达到峰值,当营养液磷素浓度达11mg/L时,再提高磷素浓度对大豆根瘤固氮率无明显促进作用;而对于大豆植株氮素积累、根瘤固氮量和产量,只有当营养液磷素浓度达到21mg/L时,再提高磷素浓度才无明显促进所用,表明满足根瘤固氮的磷素营养水平较产量形成的水平要求低。     

根系交互作用对等高绿篱—大豆间作系统N素吸收转移的影响

通过15N标记叶片和15N标记土壤的地下部分隔箱栽试验,探讨了根系交互作用对大豆/绿篱间作体系氮素吸收和转移的影响。结果表明,紫穗槐-大豆系统无隔处理大豆和紫穗槐生长被抑制,其生物量和吸氮量均低于网隔和板隔2种分隔方式;而香根草-大豆间作下,大豆与香根草的生物量和吸氮量都表现为根系无隔时最高。大豆植株体内15N丰度,香根草-大豆间作下,尼龙网分隔处理高于无隔处理,香根草则表现为无隔处理较高;紫穗槐-大豆间作下,紫穗槐和大豆体内15N丰度都表现为根系无隔处理较低。大豆和绿篱共生期内,2种绿篱都从大豆体内竞争了氮素,发生了大豆向绿篱的氮素转移。表明香根草与紫穗槐对肥料氮的竞争能力均强于大豆;紫穗槐和大豆间作表现为种间抑制作用,不利于大豆和紫穗槐生长;香根草和大豆间作表现为互补作用,营养竞争和促进同在,促进了大豆和香根草生长。     

GENOTYPIC DIFFERENCES IN ROOT MORPHOLOGY AND PHOSPHORUS UPTAKE KINETICS IN BRASSICA NAPUS UNDER LOW PHOSPHORUS SUPPLY

Application of phosphorus (P) fertilizer is important in crop production because of the low bioavailability of phosphorus to plants in both acidic and calcareous soils. Although rapeseed (Brassica napus) is generally sensitive to P deficiency, different cultivars differ widely in this respect. Differences in P uptake and utilization between two rapeseed cultivars, one P-efficient (‘97081’) and one P-inefficient (‘97009’), were evaluated in solution culture by studying the changes in root morphology and parameters of P uptake kinetics in response to low-P stress. The P-efficient cultivar had lower Km and Cmin values and higher Vmax and developed longer and denser lateral root hair with greater number of root tips and branches under low-P stress, which resulted in a better developed root system and more efficient uptake of P. That, in turn, led to higher concentration and accumulation of P in the plants, culminating in higher biomass production. However, P utilization efficiency (biomass production per unit P accumulated in plant) of the P-efficient ‘97081’ was lower than that of ‘97009’ when P was deficient. These results suggest that P efficiency in rapeseed is due to a better developed root system as well as efficient uptake of P.     

METABOLIC CHANGE,TILLERING AND ROOT SYSTEM OF BRACHIARIA BRIZANTHA IN RESPONSE TO PHOSPHORUS AND ZINC NUTRITION

Phosphorus (P) and zinc (Zn) availabilities are important to the nutrition of tropical forage grasses. In this manner, this study aimed to identify and quantify changes in metabolism, tillering, and root system of Brachiaria brizantha cv. ‘Marandu’ related to P and Zn availabilities. Plants of B. brizantha cv. ‘Marandu’ were grown in nutrient solution under five rates of P (0.1, 0.6, 1.1, 1.6, and 2.1 mmol L^?1) and five rates of Zn (0.00, 0.75, 1.5, 2.25, and 3.00 μmol L^?1), in a fractionated factorial. The interaction P x Zn rates and the Zn supply were not significant for the activity of acid phosphatase enzyme, P-use index, number of tillers, and root parameters. P-use index and enzyme activity decreased as P availability increased. The high efficiency in P use was a result of high acid phosphatase activity and P supply was essential to the development of ‘Marandu’ palisadegrass root system.     

施磷对棉花根系形态及其对磷吸收的影响

通过盆栽试验，研究了不同施磷量和相同磷量及不同磷量施在不同比例的土体中对棉花根系形态及其对磷素吸收的影响。结果表明，磷对棉花根系具有刺激作用，施磷后使棉花根系长度、根表面积和根密度增大，吸磷量增多，从而促进了棉花的生长。当磷肥施入部分土体时，其对棉花根系生长的促进作用可以用Y=X0.72来表示。     

VARIATION IN PHOSPHORUS EFFICIENCY AMONG BRASSICA CULTIVARS II: CHANGES IN ROOT MORPHOLOGY AND CARBOXYLATE EXUDATION

Increased phosphorus (P) efficiency is needed to sustain agriculture productivity on soils with low available P. Significant differences were found among Brassica cultivars for growth, P utilization, and remobilization under P deficiency (see our companion paper, Aziz et al., 2011a). To identify the possible mechanisms of P acquisition from low soluble P compounds, four cultivars (‘Rainbow’, ‘CON-1’, ‘Dunkeld’, and ‘Peela Raya’) were selected to ascertain the relationship of their differential P acquisition and growth with their root length in soil and with organic acid release pattern in solution culture experiments. For this purpose their growth and P acquisition from phosphate rock (PR) was compared with calcium di-hydrogen phosphate (Ca-P) when adding uniform dose of 100 mg P kg^?1 soil separately from the two sources. Biomass accumulation, root length, root fineness, plant P uptake and ash alkalinity was significantly (P < 0.01) different in plants of all the four cultivars when supplied with PR or Ca-P in soil. Minimum biomass produced by ‘Peela Raya’ grown with either P source was followed by ‘CON-1’, ‘Dunkeld’, and ‘Rainbow’ in ascending order. Shoot dry matter production had a significant positive correlation with root dry matter production (r = 0.85, P < 0.01), root length (r = 0.59, P < 0.05) and root P uptake (r = 0.95, P < 0.01). Cultivars varied significantly for organic acid secretion in solution culture experiment. Higher quantities of secreted citric acid, malic acid and tartaric acid in solution culture experiment were measured for ‘Rainbow’ and ‘Dunkeld’ cultivars. Efficient performance of these two cultivars for growth and P uptake was associated with their longer roots and more secretion of organic acids especially citric acid.     

水稻无侧根突变体RM109冠根的解剖学观察

对水稻无侧根突变体RM1 0 9与原品种大力 (OryzasativaL .,cv .Oochikara)的冠根组织形态进行比较 ,结果表明 ,大力品种可观察到侧根原基及侧根 ,而RM1 0 9均无 ;RM1 0 9的原生木质部间中柱鞘细胞数目减少 ,为大力的 77% ;后生木质部导管数增加 ,其导管I的数量为大力的 1 4 9% ,其导管Ⅱ的数量为大力的 3 2 1 % ,且导管排列散乱。推测其原因在于根尖生长点细胞分化异常和IAA合成能力低下     

细质沙土增施磷肥对小麦生长及氮素吸收的影响

本文应用￣（１５）Ｎ示踪技术，在黄河故道细质沙土上研究小麦增施磷肥的效应。结果表明，增施磷肥，显著提高了小麦的根量、分蘖数、单位面积穗数和籽粒产量，促进小麦对肥料Ｎ和土壤Ｎ的吸收，减少肥料Ｎ损失，提高小麦对肥料Ｎ利用率。在该中低产沙地上，磷的施用量１８０～２７０ｋｇＰ２Ｏ５／ｈｍ２效益最佳。     

施肥对农田氮磷污染物径流输出的影响研究

施肥不当是造成农田地表径流 N、P 污染的主要原因。本文采用实地调查与模拟实验相结合的方法,研究了不同肥料品种、不同施肥强度、不同施肥时间与方式对土壤地表径流 N、P 流失的影响。结果表明,农田径流 N、P 的流失量与肥料投入水平有一定的正相关性,施肥后土壤地表径流中总 P 浓度比未施肥前成倍增加。不同肥料品种以硝酸铵最易增加径流中 N 的含量;通过经济与环境协调分析,相对于其他处理而言,一定量的尿素与普钙配合施用可减少 N、P 流失,同时获得较高的白菜产量;就施肥方式而言,深施或穴施比表施可显著降低径流中 N、P 的流失量。     

METABOLITE PROFILING OF SHOOT EXTRACTS,ROOT EXTRACTS,AND ROOT EXUDATES OF RICE PLANT UNDER PHOSPHORUS DEFICIENCY

We applied a metabolite profiling technique to investigate root exudates under phosphorus (P) deficiency. Oryza sativa was grown in culture solution containing three P levels (0, 1, and 8 mg P L^?1). Shoot extracts, root extracts, and root exudates were obtained from 18 and 23-day-old plants and their metabolites were determined by capillary electrophoresis/time-of-flight mass spectrometry. Eighty, 90, and 65 metabolites were identified in shoot extracts, root extracts, and root exudates, respectively. Sixty-three to eighty-four percent of the metabolites were exuded to the rhizosphere. More than 33% of the metabolites in the root exudates showed higher concentration at low P than at high P. On the other hand, only 14% of the metabolites in the root extracts showed lower concentration at low P than at high P. These results suggest that rice roots actively release many metabolites in response to P deficiency.     

膨润土和磷肥对石灰性土壤无机磷形态转化及有效性的影响

对山西石灰性土壤无机磷的形态、加入外源磷后无机磷形态的转化及施加膨润土后对提高磷素的有效性进行了初步探讨 ,结果表明 :山西石灰性土壤中磷素以无机磷为主 ,而无机磷中以Ca P为主 ,Ca10 P和Ca8 P占无机磷总量的 85 % ,Ca2 P仅占 4 42 %。土壤加入外源磷后 ,Ca2 P有所增加 ,其次是Ca8 P、Ca10 P、Fe P ,Al P和O P增加很少。施加膨润土后使加入外源磷的土壤无机磷都有所增加 ,其中Ca2 P增加最明显 ,Ca8 P、Al P、Fe P增加较多 ,而Ca10 P和O P增加最少 ,说明施用膨润土是实现土壤无机磷释放的主要途径     

钼、锰营养对大豆碳氮代谢的影响

钼、锰是植物生长所必需的微量元素,对作物的生长发育、产量和品质都有明显影响。钼在植物氮代谢中起着关键作用,主要与钼是硝酸还原酶和固氮酶等含钼酶类的重要组成成分有关[1]。同时钼对维持叶绿体的正常结构也是必不可少的,缺钼会导致植物叶绿素含量减少,光合强度降低[2]。锰对作物的光合作用、氮、碳和脂类代谢有密切关系,并是多种酶的组分与活化剂,锰营养的丰缺对大豆的生长发育、产量及抗逆性有显著影响[3]。在钼或锰营养方面,目前研究较多是钼或锰对大豆的产量、品质和生理活性的影响,例如施钼能提高豆科植物根瘤菌数量,促进植株生长,增加生物量和产量[4~6]。锰浸种会影响大豆种子萌发和幼苗的生理特性[7],施锰     

两系亚种杂交稻根系活力和磷素分配与籽粒充实度的研究

应用放射性＾３２Ｐ示踪技术对两系亚种间杂交稻根系活力，磷素分配与籽粒充实度进行了研究，结果表明：杂交组合２２６４Ｓ／ＤＴ７１３与汕优６３相比，在抽穗期、灌浆期和成熟期根系吸收＾３２Ｐ总量较少，各生育期根系吸收＾３２Ｐ总量下降幅度大，根系活力下降快，根系出现早衰；     

苯甲酰胺对大豆辐射诱变效应的影响

本试验用苯甲酰胺、￣（６０）Ｃｏγ射线、电子束单因子及苯甲酰胺与￣（６０）Ｃｏγ射线、电子束复因子处埋大豆风干种子。结果表明，苯甲酰胺单因子处理，对大豆Ｍ１的苗高、成株率、孕性和根尖细胞染色体均无明显的影响，对其Ｍ２也无诱变效应。￣（６０）Ｃｏγ射线、电子束单因子处理，对大豆具有明显的损伤效应和诱变效应。苯甲酰胺与￣（６０）Ｃｏγ射线或电子束复因子处理，能明显增强Ｍ１的损伤效应，并能提高Ｍ２的诱变效应。苯甲酰胺具有抑制辐射损伤修复、提高诱发突变频率的作用。     

有机肥处理对小麦根系生长、活力和磷吸收的影响

通过温室砂培、室内分析，研究了有机肥、无机肥和有机无机配合对小麦根系活力、根系酸性磷酶活性、根尖呼吸作用、根系ATP酶活性，以及磷的吸收动力学参数的影响。结果表明，有机与无机肥配合施用，增加了小麦根系的活力。单施有机肥在培养初期能显著提高根系活力，培养时间增长，效果明显下降，而有机无机肥配施处理能较长时间保持根系有较高的活力。有机无机肥配合，使小麦磷吸收动力学参数发生变化，有机肥和有机无机肥配合处理使Imax增加，Km减小。结果说明，有机肥除提供小麦营养外，对其根系活力、生理代谢和吸收能力都有影响，从而直接促进了小麦对磷的吸收。     

长期施用不同肥料对土壤磷素形态转化的影响

土壤中磷素形态及其转化的研究,一直受到国内外学者的高度重视,张守敬和Jaokson⁷建议的无机磷分级体系尽管应用在酸性土壤上说明了许多理论和生产上的问题,但未能将石灰性土壤的钙磷从易溶的二钙盐到难溶的磷灰石加以区分,从而难于对其进行有效性评价,使石灰性土壤无机磷的形态形态分级研究受到限制。     

施肥深度对大豆氮磷钾吸收及产量的影响

采用分层施肥和15N示踪方法,研究施肥深度对大豆氮磷钾吸收及产量的影响,为大豆合理施肥深度的确定提供理论依据。研究表明,施肥深度对大豆前、中期植株干物质、氮磷钾的积累影响较大,而对植株成熟期影响较小;大豆苗期(V3)与种子同层施肥处理植株干物质和氮磷钾的积累量最大;盛花期(R2)以种下6cm处理效果最明显。施肥深度对大豆产量的影响也表现为种下6cm处理最高,但与种子同层施肥、种下12、18和24cm施肥处理差异不显著;施于种子同层至种下6cm最有利于大豆苗期氮肥吸收,表层施肥、种下24cm施肥处理氮肥吸收效果不好。     

MET对大豆群体发育及光合产物分配的影响

MET(Multi-Effect Triazole,多效唑)是一种新型植物生长延缓物质,在大豆始花期喷施200ppmMET,使植株个体矮壮紧凑,群体封行推迟,并提高了株间的透光率;同时,MET处理,使单株同化~(14)CO_2量显著增加,越接近成熟期喂饲~(14)CO_2,同化物向籽粒中运输的越多。MET处理对~(14)C同化物运砖的调节作用,主要表现在增加~(14)C同化物向根系及籽粒的运转。     

钾素营养对水稻根系生长和养分吸收的影响

本文研究了大田和盆栽试验中钾素营养对水稻根系形态、活力及其对养分吸收的影响。试验结果表明：（１）在氮磷肥的基础上施钾能促进稻根的生长；（２）土壤供钾潜力、钾肥种类和水稻品种的吸Ｋ特性均影响根系的生长；（３）在缺钾的酸性土壤上，吸钾强的品种，施钾的促根效应最为明显；（４）施钾能增加小于０．２ｍｍ的细根量，提高稻根的再生能力，影响Ｎ、Ｐ、Ｋ、Ｃａ、Ｍｇ等营养元素的吸收及其在地上和地下部分间的分配；（５