Soil Test to Predict the Copper Availability in Pasture Soils

Abstract

The proportion of copper (Cu) that can be extracted by soil test extractants varied with the soil matrix. The plant‐available forms of Cu and the efficiency of various soil test extractants [(0.01 M Ca(NO₃)₂, 0.1 M NaNO₃, 0.01 M CaCl₂, 1.0 M NH₄NO₃, 0.1 M HCl, 0.02 M SrCl₂, Mehlich‐1 (M1), Mehlich‐3 (M3), and TEA‐DTPA.)] to predict the availability of Cu for two contrasting pasture soils were treated with two sources of Cu fertilizers (CuSO₄ and CuO). The efficiency of various chemical reagents in extracting the Cu from the soil followed this order: TEA‐DTPA>Mehlich‐3>Mehlich‐1>0.02 M SrCl₂>0.1 M HCl>1.0 M NH₄NO₃>0.01 M CaCl₂>0.1 M NaNO₃>0.01 M Ca(NO₃)₂. The ratios of exchangeable: organic: oxide bound: residual forms of Cu in M1, M3, and TEA‐DTPA for the Manawatu soil are 1:20:25:4, 1:14:8:2, and 1:56:35:8, respectively, and for the Ngamoka soil are 1:14:6:4, 1:9:5:2, and 1:55:26:17, respectively. The ratios of different forms of Cu suggest that the Cu is residing mainly in the organic form, and it decreases in the order: organic>oxide>residual>exchangeable. There was a highly significant relationship between the concentrations of Cu extracted by the three soil test extractants. The determination of the coefficients obtained from the regression relationship between the amounts of Cu extracted by M1, M3, and TEA‐DTPA reagents suggests that the behavior of extractants was similar. But M3 demonstrated a greater increase of Cu from the exchangeable form and organic complexes due to the dual activity of EDTA and acids for the different fractions and is best suited for predicting the available Cu in pasture soils.     

Phosphorus Availability in Lolium perenne L. in Acidic and Limed Soils

Soil liming may increase phosphorus (P) availability, but this increase may also be achieved with generous P applications. However, it is not well known which practice has longer-term effects. Thus, in a pot experiment, an acidic soil (pH 4.57), limed to pH 6.5, was added with P and sown with Lolium perenne L. We conducted three cuttings (on Days 40, 80, and 120) in order to evaluate P dynamics in each of the treatments. As expected, biomass increased significantly with liming. We also found that plant P concentration increased in the liming treatment, but not in the P-added treatment, although the difference was reduced on Day 120. This shows that in severely acidic soils, liming should be preferred over P addition, although the beneficial effects may not last for a very long time, since in this experiment, they only lasted for 4 months. Similar conclusions were drawn from soil P extraction results.     

Change of Zinc Forms in Rhizosphere and Nonrhizosphere Soils of Maize (Zea mays L.) Plants as Influenced by Soil Drought Condition

A rhizobox experiment was conducted to study the changes of various zinc (Zn) forms in rhizosphere and nonrhizosphere soils of maize (Zea mays L.) plants grown under well-watered and drought conditions. The tested soil was earth-cumulic orthic anthrosol sampled from the Shaanxi Province of China. The experiment was set at two levels of Zn, 0 and 5.0 mg Zn kg^?1 soil, and at two treatments of soil water content, 45%–50% (drought) and 70%–75% (well watered) of soil water-holding capacity. A completely randomized factorial design (2 Zn treatments × 2 water levels × 3 replicates) was set up. Adequate soil water supply enhanced growth and Zn accumulation of maize plants. Applying Zn increased plant biomass and Zn content more notably under well-watered conditions rather than drought conditions. Soil Zn was defined as water-soluble plus exchangeable (WSEXC) Zn, carbonate-bound Zn (CA), iron–manganese oxide–bound Zn (FeMnOX), organic matter–bound Zn (OM), and residual Zn (RES) forms using the sequential extraction procedure. Most of Zn was predominantly in the RES fraction. Zinc application increased the contents of WSEXC Zn, CA Zn, and FeMnOX Zn in soil. When Zn was added to the soil, the concentrations of CA Zn within 0–2 mm and 0–4 mm apart from the central root compartment (CC) were greater than other zones under the conditions of adequate and limited soil water supplies, respectively. Zinc application also resulted in an accumulation of FeMnOX fractions at a distance of 2 mm from CC. The FeMnOX Zn content in this compartment increased with soil drought. Under well-watered conditions, dry-matter weight and Zn concentration of shoots presented better correlations with CA Zn and FeMnOX Zn fractions in and near the rhizosphere as compared with drought conditions. It is suggested that in an earth-cumulic orthic anthrosol, soil moisture conditions affect the transformation of the added Zn into the CA and FeMnOX fractions near the rhizosphere and their bioavailability to maize plants.     

Assessment of Suitable Extractants for Predicting Plant-available Potassium in Indian Coastal Soils

The suitability of seven chemical extractants was evaluated on 24 Indian coastal soils for prediction of plant-available potassium (K) to rice (Oryza sativa L. var. NC 492) grown in modified Neubauer technique. Average amounts of soil K extracted were in descending order: 0.5 M NaHCO₃ > neutral 1 N NH₄OAc > 0.02 M CaCl₂ > Bray and Kurtz No.1 > 1 N HNO₃ > 0.1 N HNO₃ > distilled water. The highest simple correlation with plant K uptake was obtained with 0.1 N HNO₃-K (r = 0.848) and lowest with CaCl₂-K (r = 0.805). Predictive models were developed using plant K uptake as the dependent variable and extractable soil K, sand, silt, soil pH, and electrical conductivity as the independent variables. Based on the final R² and ease of measurement, distilled water, 1 N NH₄OAc, and 0.1 N HNO₃ models were the best predictors of plant-available K in coastal soils when used along with sand or soil pH.     

Suitability of Different Soil Extractants for Determination of Available Cu and Mn Contents in Polish Soils

The aim of this study was to compare four micronutrient soil-test extractants currently in common use in Poland, Rinkis, Mehlich 3, modified Lindsay and Norvell, and Yanai, for ability to determine the plant-available concentration of copper (Cu) and manganese (Mn) in two acidic soils (pH 4.8–4.9) that had been amended with different doses of Cu and Mn fertilizers. The comparison was based on two pot experiments (each with a different soil) with corn (Zea mays), barley (Hordeum vulgare), spring wheat (Triticum aestivum), rape (Brassica napus), red clover (Trifolium pratense), and English ryegrass (Lolium perenne). The extractants were evaluated based on a correlation analysis of the microelement concentrations in plants at the end of the vegetative phase and micronutrient concentration in the fertilized soil determined by each extractant at the end of the experimental period. The largest extractable concentrations of Cu and Mn in soils were obtained with Rinkis. The modified Lindsay and Norvell soil test extracted the lowest amount of both microelements. For soil Cu, the results with the Mehlich 3 and Yanai extractants were highly correlated with the Rinkis procedure results (r = 0.98). The modified Lindsay and Norvell results were not as well correlated with Rinkis (r = 0.84). For soil Mn, the correlation of results of Yanai, Mehlich 3, and modified Lindsay and Norvell to Rinkis ranged from r = 0.80 to r = 0.86. Levels of Mn and Cu measured with each of the extractants were highly correlated with plant tissue concentrations of Mn and Cu in most of the six plant species. The exceptions to this were the following: The modified Lindsay and Norvell soil Cu levels were not correlated with ryegrass and wheat plant Cu levels; Mehlich 3 Cu was not correlated with red clover Cu; and the Rinkis-extractable Mn was not correlated with the wheat Mn. It is concluded that the Yanai and Mehlich 3 procedures are suitable alternatives to the Rinkis for Cu but not for Mn.     

Fractions of Manganese in Soil under Long-Term Experiment and Their Contribution to Manganese Availability and Uptake by Maize-Wheat Cropping Sequence

Manganese (Mn) is an essential micronutrient needed for plant growth and development, but it can be toxic to plants in excess amounts. Long-term fertilizer experiment and intensive cropping alter the soil properties and also affect its plant-available Mn contents. To understand the dynamics of Mn under long-term fertilizer experiment the present study was initiated during 1972 at the experimental farm of College of Agriculture, CSK HPKV, Palampur (32° 6′ N latitude and 76° 3′ E longitude) in a randomized block design with 11 treatments replicated three times with a maize-wheat cropping sequence. The soils of the experimental area in the beginning of the experiment were acidic in reaction and taxonomically classified as Typic Hapludalfs. Surface (0.0–20 cm) and subsurface (20–40 cm) soil samples taken after the harvest of maize (kharif, 2008) were analyzed for pools of Mn and chemical indices of soil quality using standard analytical methods. Besides, the pools of Mn were also determined in the composite soil samples drawn from adjacent fallow plots. Results showed that all the pools of Mn were noticeably greater in farmyard manure (FYM)–amended plots compared to zero-fertilized plots. Although the residual fraction was found to be the most dominant fraction, organically bound and exchangeable forms were found to play major roles in the nutrient supply, crop productivity, and nutrient uptake. The greatest productivity of maize (2008) and wheat (2008–09) was recorded under the 100% nitrogen, phosphorus, and potassium (NPK) + FYM treatment. FYM and lime treatments resulted in significantly greater uptake of all the nutrients by both the crops compared to other treatments. The organically bound fraction was found to have the greatest significant and positive correlation with yield and nutrient uptake of maize and wheat crops. Further regression analysis studies revealed that the organic form was the most important pool contributing towards the variation in the parameters. Exchangeable and organically bound forms contributed significantly towards diethylene triamine pentaacetic acid (DTPA)–extractable Mn.     

Influence of Drought Applied at Different Growth Stages on Kernel Yield and Quality in Maize (Zea Mays L.)

Drought severely affects yield and its quality in different plants. In a field experiment, maize was exposed to drought stress at vegetative, silking, and kernel-filling growth stages to determine the drought-induced changes in kernel yield and quality traits. The experiment was laid-out in a randomized complete block design with four replications. Withholding water at the vegetative stage was very effective in increasing protein, total amino acids, total soluble sugars, glucose, and sucrose contents in maize kernels. In contrast, drought applied at the kernel-filling stage increased the total free amino acids, total phenolics, and activities of catalase (CAT) and ascorbate peroxidase (APX) in maize kernels. Drought at the vegetative stage improved the kernel quality while at the silking stage severely affected kernel yield in maize. Taken together, the results suggested that incidence of drought should be avoided at the silking stage to minimize kernel yield losses and decrease in kernel quality in maize.     

Evaluation of a Suitable Extractant and Determination of Critical Limit of Boron in Soil and Mustard (Brassica Juncea L.) Plant by Various Extractants in Inceptisols of Varanasi

Pot culture experiment was conducted to evaluate the suitability of extractants and to determine the critical limit of boron (B) in soil and mustard plant in Inceptisols of Varanasi. Twenty-one bulk soil collected from different locations were used for growing mustard. Five extractants, namely hot water, hot 0.01molar (M) calcium chloride (CaCl₂), 0.01M CaCl₂ + 0.05 M mannitol, 1.0 M ammonium acetate (NH₄OAC) and 0.05 M hydrochloric acid (HCl), were assessed by correlating the amount of extractable B in untreated and B fertilizer-treated soil with Bray’s per cent yield, plant tissue B concentration and B uptake by mustard. Similarly, correlation coefficients of the B extracted by different extractants and soil properties were calculated. The suitability of B extracted by different extractants was in the order of hot 0.01M CaCl₂ (HCC-B) > hot water (HW-B) > 1.0 M NH₄OAC (AA-B) > 0.05M HCl (HA-B) > 0.01M CaCl₂ + 0.05M mannitol (CCM-B). The critical limits of extractable B in soil as determined by the graphical procedure were 0.54, 0.60, 0.36, 0.45 and 0.45 mg kg^?1 and the statistical procedures were 0.54, 0.60, 0.38, 0.46 and 0.48 mg kg^?1 with HW-B, HCC-B, CCM-B, AA-B and HA-B, respectively. Soil containing available B below the critical limit responded to B fertilization.     

石灰性土壤施用不同磷肥对玉米苗期生长和土壤无机磷组分的影响

研究旨在探讨不同磷肥品种对玉米生长发育和土壤无机磷组分的影响,以期为磷肥高效利用提供参考.采用盆栽试验,设置6个处理:磷酸一铵(MAP)、过磷酸钙(SSP)、聚磷酸铵(APP)、氮磷复合肥硝酸磷肥(NiP)、硫酸铵+过磷酸钙混施(SA+P),试验60天后测定了玉米的生物学指标和玉米植株磷素含量,同时测定了土壤有效磷与土...     

Evaluation of Extractants for Boron under the Influence of Organic Matter and Applied Boron in Rhizosphere and Nonrhizosphere Soils Growing Rape (Brassica campestris L.)

Field experiments during 2006–07 and 2007–08 were conducted in an Aeric Endoaquept to evaluate extractants suitable for boron (B) under the influence of organic matter and B in both rhizosphere (R) and nonrhizosphere (NR) soils with rape (Brassica campestris L.) as a test crop. The results reveal that the average B content in Mehlich 3 (MH-3) B was greatest (0.791 mg kg^?1) in NR soil, while that of the same in R soil was greatest (0.785 mg kg^?1) with Mannitol–calcium chloride (CaCl₂) (MCC) followed by hot -CaCl₂ (HCC, 0.750 mg kg^?1) in the treatment T₄ where NPK (80:40:40), B at 0.5 kg ha^?1, and farmyard manure (FYM) at 5 t ha^?1 were applied together. Based on linear regressions and correlations between different extractants and yield responses, the MH-3 extractant gave the greatest value of co-efficient of determination (R² = 0.36**, r = 0.598**) and has proved to be a superior extracting solution for B in NR in an Aeric Endoaquept. The results further suggested that the extractability of B with these three extractants did not have any control over rhizosphere soil zone.     

Assessing the Feasibility of Olsen P and P Sorption Parameters in Acidic Soils

Plant-available phosphorus (P) and P adsorption capacities are important for crop growth in acidic soils. Olsen P test, which is based on extraction with bicarbonate for predicting the amount of soil P available to plants, was used in this work. Soil P-adsorption capacities were determined by Langmuir line equation. The purpose of this work was to examine the suitability of Olsen P for predicting phytoavailable P and P sorption parameters in acid soil. To this end, we (i) assessed the phytoavailable P by successively pot-cropping rice and (ii) P adsorption characteristics of soil and their relation with Olsen P. Plant-available P, estimated by Olsen P in tested soil, was correlated to labile P. Qm (phosphorus sorption maximum) was negatively correlated with K (P sorption strength). P buffering capacity of soils was P3 (the highest P rate) >P2 (the second highest P rate) >P1 (the lowest P rate) >P0 (no P adding) after 75 day’s rice growth, which indicated P replenishment capacity was different among P treatments. This also suggested that P of plant uptake may decrease soil buffering capacity, especially for soils that contained relatively lower amounts of P. Qm and K were not significantly correlated to Olsen P. Degree of P saturation and Olsen P shared the similar trend with the change of P application rates and sampling dates. We concluded P status in soil can be characterized by degree of P saturation and Olsen P in tested soil. They were able to explain P status from both agronomic and environmental aspects.

Abbreviations: Qm, P sorption maximum; K, P sorption strength; P3, highest P rate in soil; P2, second highest P rate in soil; P1, lowest P rate in soil; P0, P adding in soil.     

Effects of Soil Fertility Management on Growth,Yield, and Water-Use Efficiency of Maize (Zea mays L.) and Selected Soil Properties

Maize was grown for two cropping years to investigate the supplementary effect of inorganic fertilizer with cow dung on growth, yield, water-use efficiency, and soil properties. Five treatments were imposed: unfertilized control and four different fertilization packages comprising two different levels of inorganic fertilization with cow dung as supplements, sole inorganic fertilizer, and sole cow dung. Results analyzed after the two cropping years showed significant differences in growth and yield. A reduction in yield was observed for the unfertilized plots, whereas yields in the plots of supplemented inorganic fertilizer with cow dung increased and were significantly at par with the sole inorganic fertilizer plot. Water-use efficiency was improved for the fertilized plots. Significant improvement was observed in the water-stable aggregates with plots that received cow dung as organic manure either in part with inorganic fertilizer or as sole cow dung.     

氟对土壤理化性质和玉米生长的影响

用盆栽试验研究了外源氟对潮土、黄棕壤pH、容重、玉米干物重和吸钾量的影响,结果表明：氟可以提高土壤pH,使土壤结块,容重增加,孔隙度减少,加入氟1000 mg/kg,黄棕壤和潮土pH分别比对照增加了0.77和0.52,土壤容重分别增加了26.98%和27.72%。氟对潮土过氧化氢酶活性没有影响,加入氟600 mg/kg,氟对黄棕壤过氧化氢酶活性产生明显抑制作用;氟对黄棕壤碱性磷酸酶活性无影响,氟400 mg/kg对潮土碱性磷酸酶活性产生明显抑制。加入氟600 mg/kg,土壤中性磷酸酶活性明显降低;氟对黄棕壤酸性磷酸酶活性影响较潮土小。脲酶活性对氟最为敏感,在黄棕壤和潮土中,分别加入氟200 mg/kg和400 mg/kg,土壤脲酶活性明显降低。玉米苗期,氟浓度在400 mg/kg以上,才会对玉米苗期干物质积累产生影响,加入氟1000 mg/kg,黄棕壤和潮土玉米幼苗干物重比对照分别减少了20.1%和9.8%,氟对黄棕壤玉米苗期生长影响比潮土大;随着玉米生长,氟对玉米干物重产生明显影响的浓度越来越低,在玉米拔节期,氟浓度在200～400 mg/kg时,玉米地上和地下部干物重比对照明显减少,氟对玉米根的抑制作用超过玉米地上部。氟对玉米吸钾量影响很大,加入氟浓度高于400 mg/kg时,玉米吸钾量明显减少。加入氟1000 mg/kg,潮土玉米含钾量与对照相比减少了43.7%,黄棕壤玉米减少了41.9%。潮土玉米吸钾量与对照相比减少了59.7%,黄棕壤玉米吸钾量减少了50.9%。     

Maize (Zea mays L.) yield and soil properties as affected by no tillage in the black soils of China

A four-year tillage experiment on maize was conducted in the high latitude region of Northeast of China. The main objective of this study was to investigate the effects of different field tillage practices on maize grain yield, soil physical properties, and soil water and temperature dynamics in Northeast of China. The tillage practices included moldboard plow tillage (MOT), rotary tillage (ROT), reduced tillage (RET), combined tillage (COT), and no tillage (NOT). The surface soil water content at depths of 0–20 cm was higher under NOT compared with other tillage practices, but not different at the deeper soil depths in 2011. The soil temperatures under NOT and RET were lower than those under moldboard plow tillage and ROT at depths of 5 and 15 cm, respectively, measured at 9:00 am in 2005. From the hourly dynamics of soil temperature, the differences among the tillage practices mainly appeared during the daytime (from 8:00 am to 7:00 pm). Among all the practices, the average daily soil temperature under ROT was the highest, while that under NOT was the lowest. MOT, ROT, and RET had higher soil accumulative infiltration compared with NOT and COT. The surface soil bulk density under NOT was higher than or equal to that under the other four tillage practices. The maize yields under NOT were the lowest among all the tillage practices for three years straight. Meanwhile, the yields under MOT were the highest, which were about 47%, 61%, and 38% higher than those under NOT. NOT practice is not recommended for use in spring-planted maize under the high latitude humid cool climate Mollisol region in Northeast of China.     

白云石粉对皖南酸性红黄壤磷组分及磷有效性的影响

在施用P肥的基础上配合使用白云石粉,用酸性土壤无机P分级方法测定皖南红黄壤各形态P的含量。结果表明:使用P肥能明显提高土壤全P、无机P和土壤速效P含量;土壤速效P与无机P各组分的相关性以Al-P最好,Fe-P、O-P次之,Ca-P最差。施用白云石粉,当季土壤Ca-P含量及其在无机P中所占的比例明显提高,Al-P的形成受到抑制,但随着时间的推移,却更有利于有效性较高的Al-P含量的增加。     

Effects of Soil-Applied Materials on the Dry Weight and Boron Uptake of Maize Shoots (Zea Mays L.) Under High Boron Conditions

High concentrations of boron (B) in the soil, reduces plant growth, crops’ yield and quality. Regarding such problem, synergistic and antagonistic relations between the nutrients can be used to ameliorate the B toxicity. Therefore, a greenhouse experiment was conducted to evaluate effects of soil-applied zinc (Zn), nitrogen (N), calcium (Ca), lime (CaCO₃), potassium (K), humic acid (HA), and humus on the dry weight and B uptake of maize shoots (Zea mays L.) under high-B containing soil conditions. Increasing doses of B (0, 2.5, 5, and 10 mg kg^?1 B) were applied to soil as borax (Na₂B₄O₇10H₂O), and boric acid (H₃BO₃). Positive correlations were found between B doses and the uptake amounts (r = 0.934**; – 0.964**). However, the correlations between the dry weight and B doses (r = ?0.314**; – r = ?0.495**) and between the dry weight and the uptake amounts (r = ?0.294*; – r = ?0.497**) were negative. Among the materials, Zn and humus exhibited positive correlations with dry weight values (r = 0.249*; r = 0.525**), and an effective increase (p < 0.01) in the dry weight amounts of maize shoots was observed under toxic B conditions.     

Critical limit of boron for maize (Zea mays L.) in red and lateritic soil of Jharkhand,India

ABSTRACT

To establish a critical limit in soils and plant, an experiment was conducted in red and lateritic soil (Alfisols) of farmer’s field in tribal-dominated Panchayat Kurum, Palkot block, Gumla district, Jharkhand, India. Based on the results of the field experiment, the critical limits were determined as 0.48, 0.50, 0.47, and 0.42 mg kg^?1 in the soil, respectively, for hot water, hot calcium chloride, salicylic acid, and ammonium acetate-extractable B, while a critical limit of 12.00 mg kg^?1 was observed in maize tissue using the graphical method. In an analysis of variance method, the critical limits of B in soils were found as 0.45, 0.54, 0.49, and 0.43 mg kg^?1 using hot water, hot calcium chloride, salicylic acid, and ammonium acetate extractants, respectively. Maize plants were highly responsive to B application where soil B level was below the critical limit (0.50 mg kg^?1). In a field experiment, grain yield of maize increased with increasing levels of B application, while soil application at 1.0 kg ha^?1 + two foliar application (at the knee and pre-flowering stages) of borax at 0.2% were showed significantly higher grain yield of the maize crop. The hot water, hot calcium chloride, salicylic acid, and ammonium acetate-extractable B were significantly and positively correlated with organic carbon and negatively correlated with the electrical conductivity of soils.     

Total Chromium Captured by Maize (Zea Mays) Plants is Increased by Phosphate and Iron Supplementation in the Soil

In this work, a commercial hybrid maize was used, and the effect of selected mineral nutrients [sulfur (S), phosphorus (P), iron (Fe), and nitrogen (N)] on the chromium (Cr) captured by plants was analysed. Seeds were germinated in vitro, and plants were transferred to pots with soil supplemented with a growth inhibitory Cr concentration and different mineral nutrient combinations. Plants were grown for 13 weeks and irrigated with water. In the harvested plants, total Cr was determined considering the Cr concentration in tissues and the biomass as dry weight. The soil supplemented with phosphorus (P) or Fe improved the total Cr captured by plants by a quarter. Bioconcentration values in plant tissues were similar to those of other plants grown in soil with Cr. This information will be useful either for Cr phytoremediation or to protect commercial maize crops cultivated in Cr contaminated soils.     

The Determination of Soil Boron Fractions,Their Relationships to Soil Properties and the Availability to Olive (Olea europea L.) Trees

This study was conducted to investigate the various boron fractions in olive tree grown soils. The correlations between boron fractions in leaves, fruits and soil properties were examined. For this purpose cv “Gemlik” olive (Olea europaea L.) orchards were visited. Soil samples from 0–30 cm and 30–60 cm deep, the leaf and fruit samples were collected. The greatest proportion of total soil boron is present in residual form (85–88%). It is followed by organically bound B (2.84–4.50%), specifically adsorbed on soil colloid surfaces (0.93–1.31%), oxides (manganese oxyhydroxides, amorphous Fe and Al oxides, crystalline Fe and Al oxides) bound B (7.27–8.31%). The smallest one readily soluble (extracting plant available) boron values were composed of only 0.40–0.50% of total boron ranging. To determine readily soluble boron five different extraction solutions were in the order Hot water ? 0.01 M CaCl₂ ? 1 M NH₄OAc ? 0.1 M KCl ? 0.005 M DTPA. Fruit boron concentration and soil boron fractions showed close correlations than leaf boron concentration.     

玉米单倍体胚性愈伤的诱导与鉴定

为建立一套适合玉米单倍体胚性愈伤培养和快速筛选体系,以单倍体诱导系MT-1为父本,18-599红为母本进行单倍体诱导,设置暗培养、全光照培养和光暗周期培养3种光照培养方式,均分别培养0、1、5、10、20、40 h后,观察幼胚形态和颜色。结果表明,自交系18-599红的单倍体和二倍体幼胚均能正常诱导形成胚性愈伤组织;不同光照培养方式对紫色(二倍体)愈伤率的检出效果依次为光培养>光暗周期培养>暗培养。通过光照筛选的方法可在早期鉴定愈伤组织,其二倍体愈伤的筛选率在培养20 h时可达68%,40 h时为71%,剔除了大部分非单倍体愈伤,综合分析确定光照强度为2 000 lx、20℃处理20 h为最适光照筛选处理。染色体压片技术获得的拟单倍体愈伤中有二倍体愈伤的检出,但经流式细胞仪检出获得的拟单倍体愈伤再经染色体压片检测,无二倍体愈伤,表明流式细胞仪检测单倍体愈伤的准确性高于染色体压片技术。通过光照初步筛选结合流式细胞仪的精确鉴定,迅速从3 000个单倍体愈伤中获得110个单倍体愈伤,单倍体愈伤率3.67%。本研究结果为以玉米单倍体愈伤为转基因受体,快速获得转基因植株提供了一定的技术支撑和理论参考。