Effect Of Different Plant Densities Research Articles

Effect of Plant Density on Growth and Bioactive Compounds in Salvia miltiorrhiza

Danshen (Salvia miltiorrhiza) is an herbaceous plant widely used in the pharmaceutical industry. However, the majority of medicinal plants utilized in the US are imported, posing challenges such as fluctuations in bioactive compound concentrations and insufficient supply to meet demand. Determining the optimal plant density is a key management decision for danshen production. This study aimed to investigate the effects of different plant densities on the growth and bioactive compound content of danshen cultivated in Mississippi. A field experiment was conducted to investigate the effects of different plant densities on individual plant growth, photosynthesis, and the content of bioactive components in danshen in 2020 and 2021. Six plant densities were designed: 30 × 20 cm (between row spacing × within row spacing), 30 × 30 cm, 30 × 40 cm, 45 × 20 cm, 45 × 30 cm, or 45 × 40 cm. A plant density of 45 × 40 cm resulted in danshen plants exhibiting the highest Plant Growth Index (PGI), SPAD, root number, shoot number, shoot fresh and dry weight, maximum root diameter, maximum root length, net photosynthesis, intracellular CO2 concentration, tanshinone I, and cryptotanshinone, regardless of year. Plants spaced at 45 × 30 cm had similar root fresh weight, root dry weight, and tanshinone IIA and salvianolic acid B levels compared with plants grown at the 45 × 40 cm spacing, and both were significantly higher than other densities.

Growing Coffea canephora in agroforestry systems with Brazilian firetree, Brazil nut, and teak

Planting coffee in agroforestry systems (AFSs) provides diverse advantages to farmers interested in producing environmental services, such as increased local biodiversity, reduction in soil erosion, improvement in water infiltration into the soil, and regulation of climate extremes. It can also be economically attractive due to the possibility of serving alternative markets that have higher and more stable prices for coffees integrated into alternative systems and the generation of products complementary to coffee. This study aimed to evaluate the effects of different planting densities of three forest species on the composition of AFSs with coffee plants under the conditions of the southwestern Amazon region. The study was conducted from November 2014 to June 2021 in the experimental field of Embrapa in Ouro Preto do Oeste, RO, Brazil. The coffee plants were intercropped with three forest species: i) Brazilian firetree (Schizolobium parahyba var. amazonicum), ii) Brazil nut (Bertholletia excelsa), and iii) teak (Tectona grandis). The treatments used in each experiment were four plant densities of plants: zero (coffee plants only, in full sun), 111 plants ha−1 (10 × 9 m), 222 plants ha−1 (10 × 4.5 m), and 444 plants ha−1 (5 × 4.5 m). The experiments were conducted in a split-plot arrangement, with plots consisting of plant densities and subplots consisting of harvest periods (crop seasons). The experimental design was completely randomized, with nine replications. The part of the plot used for data collection consisted of one planted row with 12 coffee plants. The average and accumulated productivities of coffe plants were evaluated over five harvests (2017-2021). Afforestation of the coffee field with Brazilian firetree plants reduces the mean yield and cumulative yield of C. canephora ‘Conilon’ in the first five commercial crop years. Brazil nut and teak planted at densities of up to 222 trees per hectare did not lead to a reduction in the mean and cumulative yield of coffee plants.

Increasing planting density can improve the yield of Tartary buckwheat.

Planting densities and nitrogen fertilizer application rates determine the yield of crops. Tartary buckwheat is a pseudocereal crop with great health care and development values. However, little is known about application of nitrogen fertilizer and planting density on the physiological characteristics of Tartary buckwheat. This study aims to clarify the effect of planting density on the senescence and yield of Tartary buckwheat under low nitrogen conditions. A 2-year field experiment was conducted on Tartary buckwheat (Jinqiao 2) to study the effects of different planting densities (8 × 105, 10 × 105, 12 × 105, 14 × 105, and 16 × 105 plants·ha-1) on the root morphology and activity, chlorophyll and malondialdehyde (MDA) contents, antioxidant enzyme activity, photosynthetic characteristics, agronomic traits, and yield of Tartary buckwheat in the absence of nitrogen fertilizer treatment. With the increase in planting density, the root morphological indices and activities; chlorophyll a, chlorophyll b, and carotenoid contents; superoxide dismutase and peroxidase activities; net photosynthetic rate; transpiration rate; intercellular CO2 concentration and transpiration rate; main stem node, branch, and leaf numbers; grain number and weight per plant; and 1000-grain weight of Jinqiao 2 decreased continuously, whereas plant height and leaf MDA content increased continuously. The yield of Tartary buckwheat first increased and then decreased with the increase in planting density. The yield under 14 × 105 plants·ha-1 treatment increased by 68.61%, 44.82%, 11.00%, and 22.36%, respectively, relative to that under 8 × 105, 10 × 105, 12 × 105, and 16 × 105 plants·ha-1treatments. In summary, planting at an appropriately high density (14 × 105 plants·ha-1) can promote the increase in the yield of Tartary buckwheat populations under low nitrogen conditions and is recommended for use in production to achieve the high-yielding and nitrogen saving cultivation of Tartary buckwheat. This research can serve as a theoretical basis to jointly achieve the high yield and nitrogen saving of Tartary buckwheat.

Effects of Planting Density of Poaceae Species on Slope Community Characteristics and Artificial Soil Nutrients in High-Altitude Areas

Ecological restoration of slopes in high-altitude areas is usually difficult. Gramineae species are widely used in slope vegetation restoration due to their strong adaptability and rapid growth. In the process of ecological slope protection, increasing the seeding rate of gramineous species usually improves the success rate of slope vegetation restoration, but the long-term effect is not obvious. Therefore, choosing an appropriate planting density of grass species is beneficial to the sustainable restoration of slopes in high-altitude areas. This study evaluated the effects of different planting densities of Poaceae species on community characteristics and artificial soil nutrients on high-altitude slopes. The slope ecological protection engineering experiment was carried out in Jiuzhaigou County, Sichuan Province. Commercial seed mixtures of five grasses and legumes were sown at three different planting densities of Poaceae species (10, 5, and 1 g/m2). Plant community species composition, community diversity index, and soil-available nutrients were determined annually. The results showed that there were differences in the species composition of the slope plant community under different planting densities. There was a significant negative logarithmic correlation between the community diversity indices and the planting density of grass species, and it changed with the recovery time. There were significant differences in hydrolyzed nitrogen, available phosphorus and available potassium in artificial soil, and they decreased with a logarithmic function of the recovery time. There was a positive correlation between the community diversity indices and the soil nutrient content. Overall, our study shows that low planting densities of Poaceae species are beneficial to the long-term stability of ecological restoration when ecological slope protection works are performed on slopes in high-altitude areas.

English

A study was carried out at two sites in Tanzania to assess the effect of different planting densities on growth and yield of five recently released bush bean varieties. The experiment was laid out in a split-plot design in a factorial arrangement with three replications during long and short rainy seasons of 2019/20 and 2020/21. The treatments comprised five bean varieties; TARIBEAN 1, 2, 3, 4 and 5 and five plant population densities; 200000, 222222, 250000, 266666 and 333333 plants/ha. Variables evaluated were plant height, angular leaf spot and common bacterial blight disease scores in leaves, number of pods per plant, number of seeds per pod, hundred seed weight and grain yield. The variables were subjected to ANOVA and means of statistically significant variables to plant density, variety, and environment were analyzed by Tukey HSD test and “which-won-where” view of the GGE biplot. The interaction of factors only affected significantly plant height and yield. Highest grain yield of 1,353 and 1,607 kg/ha were recorded by plant density of 200,000 plants/ha and TARIBEAN 1 variety at Maruku site during short rainy seasons (E2). Therefore, a plant density of 200,000 plants/ha and TARIBEAN 1 variety are recommended in all four environments. Key words: Plant density, bean varieties, grain yield, environment, GGE biplot, “which-won-where”.

Effects of different planting distances and fertilizer use on the remediation of farmland contaminated with Cd by intercropping Cucurbita moschata and Amaranthus hypochondriacus L.

Selecting suitable agronomic measures can strengthen the application of intercropping in the remediation of cadmium (Cd)-contaminated soil. In this study, the effects of different planting densities and fertilizer applications on the crop growth and Cd absorption of a pumpkin (Cucurbita moschata)-Amaranthus hypochondriacus L. intercropping system was determined. The goal was to provide enhanced means and a scientific basis for the promotion and application of this intercropping system. The Cd content of pumpkin in different planting systems was lower than the national food safety standard (0.05mgkg-1). In the IN-1 (4 pumpkin plants intercropped with 200 A. hypochondriacus plants) and IN-2 (4 pumpkin plants intercropped with 400 A. hypochondriacus plants) intercropping systems, the bioconcentration amount (BCA) per plant of Cd in A. hypochondriacus increased by 32.43% and 25.25%, respectively, compared with that of the monocropping system (P < 0.05). The IN-2 system had the highest equivalent ratio of heavy metal removal (3.08), indicating that this model had a substantial advantage for removing Cd. The land equivalent ratio of IN-1 (2.89) and IN-2 (2.60) was significantly higher than that of other intercropping systems, indicating that these two models had obvious yield advantages. In our study, chicken manure was the best at promoting the growth and yield of the two plants and sludge treatment significantly enhance Cd absorption of A. hypochondriacus. In general, intercropping four pumpkin plants with 400 A. hypochondriacus plants and applying chicken manure fertilizer can strengthen the application of this intercropping system in Cd-contaminated soil.

Effects of planting density on photosynthetic characteristics of flag leaf and senescence of leaf and root under wide-width sowing condition.

To determine the optimal planting density under wide-width sowing condition, we investigated the effects of different planting densities on photosynthetic characteristics of flag leaves, senescence characteristics of flag lea-ves and roots, grain yield, and water use efficiency under four planting density levels, 90×104 plants·hm-2 (D1), 180×104 plants·hm-2 (D2), 270×104 plants·hm-2 (D3) and 360×104 plants·hm-2 (D4), in field condition set in Yanzhou, Shandong during the growing season of 2018-2019 and 2019-2020. The results showed that compared with D1 and D4 treatments, D2 treatment significantly improved photosynthetic characteristics of wheat flag leaves during grain filling, increased the activity of superoxide dismutase (SOD) and soluble protein content, reduced the malondialdehyde (MDA) content, and delayed the senescence of flag leaves and roots. Compared with other treatments, D2 treatment significantly increased root length, root surface area and root volume in 0-40 cm soil layer. Compared with D1, D3 and D4 treatments, the grain yield of D2 treatment was increased by 11.8%, 2.5%, 6.4% in 2018-2019 and 22.7%, 5.7%, 17.1% in 2019-2020, respectively. In addition, water use efficiency was increased by 9.2%, 8.8%, 14.2% in 2018-2019 and 21.1%, 6.2%, 21.5% in 2019-2020, respectively. The planting density at 180×104 plants·hm-2 improved photosynthetic characteristics of flag leaves and root morphology during filling stage, delayed plant senescence, increased grain number per spike and grain weight. Consequently, the highest grain yield and water use efficiency were obtained under D2 treatment, which was the optimal treatment under the experimental wide-width sowing condition.

The Effect of Different Planting Densities on Yield Yield Components and Some Quality Properties of Virginia (Sun-Cured) Tobacco in Adıyaman Province

The Effect of Different Planting Densities on Yield Yield Components and Some Quality Properties of Virginia (Sun-Cured) Tobacco in Adıyaman Province

Mechanized Hybrid Rice Seed Production: Planting Density, the Flight Height of an Unmanned Aerial Vehicle, Fertilizer Application, and the Row-Ratio of Parents

The mechanized seed production of hybrid rice (Oryza sativa L.) represents significant progress in modern agriculture. However, the technologies and the crop management strategies in mechanized hybrid rice seed production are still immature. The present study was conducted with three field experiments to explore the effects of different planting densities, the flight height of an agricultural unmanned aerial vehicle (AUAV) for assisting the pollination, fertilization techniques, and the row-ratio of the restore line and the sterile line on seed yield in hybrid rice seed production. In experiment 1, three planting densities “DS1: 250000 hills per ha; DS2: 285000 hills per ha; DS3: 3,33,000 hills per ha” and three flight heights of an AUAV (FH1: above ground 2 m; FH2: above ground 3 m; FH3: above ground 4 m) were adopted. The results showed that DS1 and DS2 treatments produced a higher seed yield than the DS3 treatment, and the seed yield in the FH2 treatment was significantly higher than FH1 and FH3. In experiment 2, two fertilizer application methods, mechanized deep placement of fertilizer and traditional manual broadcasted fertilizer, were adopted. The results showed that deep placement of fertilizer significantly increased seed yield by increasing the effective panicle number and the grain number per panicle. In experiment 3, three row-ratios of sterile line and restore line at 8:1 (R1), 9:1 (R2), 10:1(R3) were adopted, and the highest seed yield was recorded in the R1 treatment.

Growth, yield and economics of hybrid maize (Zeamays L.) as affected by plant density and fertilizer levels

A field experiment was conducted during rabi season of 2021–2022 at the Bagusala Experimental Farm of MSSSoA, Centurion University of Technology and Management, Gajapati, Odisha, to find out the influence of plant density and levels of fertilizer on growth, yield and economics of maize. Split plot design was adopted to conduct the experiment with 3 plant densities as main plot (P1: 76923, P2: 66666 and P3: 55555 plants/ha) and 4 levels of fertilizer as subplots (F1: 75% of recommended dose of fertilizers (RDF), F2: 100% RDF, F3: 125% RDF and F4: 150% RDF) having total twelve treatment combinations and three replications. The results revealed that there was no significant effect of different plant densities of maize on growth attributes such as plant height, number of leaves/plant and leaf area index (LAI) during peak period. But the treatment P1: 76923 plants/ha, showed significantly higher dry matter accumulation as well as yield compared to remaining plant densities. However, among the levels of fertilizers F4: 150% of RDF resulted significantly higher all the growth and yield parameters. The treatment combination P1F4 (P1: 76923 plans/ha along with F4: 150% of RDF) proved as best treatment combination because of highest net return (Rs. 83032/-) and B:C ratio (1.65).

Response of Finger Millet (Eleusine coracana L.) to Varying Levels of Plant Density and Nitrogen

A field experiment was conducted during kharif, 2019 at College Farm, Professor Jayashankar Telangana State Agricultural University, Telangana. The present study was conducted to know the effect of different planting densities and nitrogen levels on the growth and yield of Finger millet. The soil of experimental site was loamy sand type, slightly acidic in pH (6.43), non-saline in EC (0.15 dSm-1), low in organic carbon (0.42%), low in available N (201.6 kg ha-1), medium in available P (25.3 kg ha-1), low in available K (236.25 kg ha-1). The experiment was laid out in randomized block design with factorial concept and replicated thrice with 12 treatments combinations consisting of four nitrogen levels (0 %, 50%, 100% and 150% RDN) and three levels of planting density (S1-solid rows × 15 cm, S2- 30 cm × 15 cm, S3- 25 cm × 15 cm). Results indicated that S1-solid rows × 15 cm recorded highest plant height, number of tillers m-2, dry matter production (g m-2) and S3- 25 cm × 15 cm recorded highest leaf area plant-1 and yield. Application of 150% RDN recorded highest plant growth parameters, grain yield and straw yield. However, it was on par with 100% RDN. It was concluded that planting density of 25 cm × 15 cm among spacings and 100% N among nitrogen levels proved to be a viable option for getting higher productivity and profit under rainfed conditions of central agro climatic zone of Telangana.

Retraction Note: Comparative analysis of nutritional components of maize with different planting densities from the perspective of ecological environment

The yield and quality of maize grains are determined by genotype and environmental factors. Through a systematic comparison of the density effects of maize yield and quality of different plant-type varieties grown on land under four different ecological environments in a certain province, and the differences in maize yield and quality in different ecological regions, the reasons for the differences were analyzed. The results showed that differences in light, accumulated temperature, and precipitation are important reasons for yield differences, and these factors are also key factors affecting maize grain quality. Taking the southern ecological zone as an example, the effects of different planting densities on the content of nutrients such as protein, starch, and fat in maize grains were studied. The study found that with the increase of planting density, the grain protein content decreased significantly, while the increasing and decreasing trend of protein, fat, and starch content (PFSC) was more complicated. By formulating maize varieties, density, and other related control measures to make full use of ecological resources and give play to regional advantages, high-quality and high-yield maize can be achieved.

The Effects of Different Planting Densities on Lentil (Lens culinaris Medic.) Yield and Yield Components in Mardin Conditions

In this study, the effects of four different sowing densities (200, 250, 300 and 350 seed m-2) on the yield and yield components for two winter lentil cultivars (Şakar and Fırat-87) in Mardin conditions. The study was laid out in a factorial randomised block design with three replicates at the fields of Mardin Artuklu University, Kızıltepe Vocational High School in 2012-2013 growing season. In the study were investigated the effect of planting densities on the plant height, first pod height, numbers of branche, numbers of pod per plant and numbers of seed per plant, numbers of seed per pod, seed yield per unit area, harvest index, biological yield and 1000 seed weight. While the highest seed yield per area was obtained from second plant density and Şakar variety with 275.23 kg da-1, the lowest seed yield per area was obtained from first plant density and Fırat-87 variety with 208.83 kg da-1.

Determination of The Effect of Different Plant Densities and Nitrogen Doses on Agronomical Traits of Sweet Corn (Zea mays saccharata Sturt.) In Conditions of The Northern-East Transitional Region Conditions of Turkey

This study was carried out to determine the differences in yield and quality characteristics of different plant density and nitrogen doses in sweet corn (Zea mays L. saccharata Sturt) during 2017 and 2018 years. This research was conducted according to a split-plot design with three replications in the Bingol University Faculty of Agriculture Application and Research Farm. Vega sweet corn hybrid was measured with three intra-row spacing (15, 20, 25 cm) and five pure nitrogen doses (0, 80, 160, 240, 320 N kg ha-1) were grown. In the study, the increasing nitrogen dose showed a significant rise in number of ears per plant , number of kernels per ear, relative chlorophyll content, water-soluble solids content, and fresh ear yield . It was determined that plant density positievly effected fresh ear yield; but the number of kernels per ear, the number of ears per plant, relative chlorophyll content were decreased. The highest fresh ear yield was determined D15 (13106 kg ha-1) in terms of plant density and N3 (15905 kg ha-1) in terms of nitrogen dose according to the combined experiment years analysis. Considering the average of years, 240 N kg ha-1 (N3) and approximately 100000 plants per hectare (S15) for optimum the fresh ear yield fertilizer application are recommended.

Impact of Nitrogen Levels and Planting Density on the Growth and Yield of Okra (Abelmoschus esculentus L. Moench)

The study was carried out to the effects of different plant densities and nitrogen levels on okra yield and plant development. Field trials were conducted in two locations, the training fields of the Ege University, Ödemiş Research and Training area, and Ege University Faculty of Agriculture, Menemen Research and Training Farm. The field layout was a split-plot design with 3 replicates, where main plots consisted of nitrogen applications and sub-plots of plant densities. Fertilizer was applied in the form of Triple Superphosphate, Potassium Sulfate, Urea and Ammonium Nitrate. Five different nitrogen levels (F1: 0, F2: 40, F3: 80; F4: 120 and F5: 160 kg N ha-1) and two different rows spacing (PD1: 15 cm×70 cm and PD2: 25 cm×70 cm) have been tested. Yield and yield components, plant height at flowering, height of the first fruits, the number of leaves, the number of branches, the number of days from sowing to first flowering, the number of days from sowing to first harvest, plant height, foliation status, total yield, yield of plant, average fruit weight, fruit length, fruit diameter have been noted in the field experiments. Total yield ranged from 5923.8 to 12888.9 kg ha-1 at the Ödemiş location, while it was 3363.3-5009.2 kg ha-1 at the Menemen location. In conclusion, the highest yield is taken from F2 in both plant densities in Ödemiş. In Menemen, the highest yield is taken from the dose of F3 (80 kg Nha-1) and F4 (120 kg Nha-1).

Economic efficiency of growing oreganum vulgare (Origanum vulgare L.) by seedling method of reproduction in conditions of drop irrigation

A study was conducted to establish the effect of different planting densities of oregano plants on its yield under drip irrigation. The economic estimation of the developed technologies of cultivation is executed. The profitability of crop production in the first and second year of cultivation was calculated. It is established that the economic indicators in the first year of growing oregano are not high, due to the low yield of dry raw materials — a biological feature of the culture. In the second year of growing oregano, the yield of dry raw materials was much higher, as a result, economic indicators were quite high, the profitability of production ranged from 162.1 to 264.4%. Based on the analysis of the cost structure, the factors that most significantly affect the cost of raw materials are identified. The high efficiency of the seedling method of growing oregano under conditions of drip irrigation has been proved.

Effects of Plant Density and Row Spacing on Yield and Yield Components of Peanut (Arachis hypogaea L.) on the Coastal Sandy Land Area in Nghe An Province, Vietnam

Background: Understanding the effects of different plant densities and row spacing on yield and yield components of peanut L14 is essential for designing and adjusting management practices to improve yield. Methods: Five planting densities were tested in Randomized Complete Block Design with three replications in 2019 spring crop on the coastal sandy land area in Dien Chau district, Nghe An, Vietnam. Result: The different density treatments affect the growth, development and yield of the peanut variety L14. With increasing plant density, the number of pod per plant, 100 pods weight, 100 seeds weight decreased, whereas plant height, leaf area index, dry matter production increased. Population yield increased with increasing plant density from the lowest density of 25 plants m-2 (2.78 tons ha-1), reached the highest at 35 plants m-2 (4.53 tons ha-1), then decreasing with increasing plant density. Peanut variety L14 is grown in plant densities and row spacing of 35 plants m-2 (25 cm × 25 cm) and 40 plants m-2 (25 cm × 20 cm) are most appropriate; plants grow, develop better and give a higher yield than other densities under the same conditions.

The Effects of Different Planting Densities and Pruning Methods on Changes of Endogenous Hormone Levels in Shoot Tips and Flowering in ‘Gemlik’ Olive Cultivar

Olive cultivation tends to adopt new planting density and pruning systems in domestic olive types in Turkey. The effect of different planting densities and pruning types on the changes of some endogenous plant hormones in shoot tips and flowering in ‘Gemlik’ olive cultivar was studied. The two-year-old seedlings were planted at 5 × 5 m, 4 × 3 m and 4 × 1.5 m densities, and were pruned as either open vase or vertical axe styles in addition to unpruned control. The shoots were taken monthly during the two successive years for hormone analysis. The levels of ABA, IAA, GA3 and Z were determined in the shoot tips. GA3 was determined to be the highest on each month whereas Z was the lowest in shoot tip samples at most of the sampling dates. Pruning types affected ABA, GA3 and IAA, but not Z levels. Planting densities had significant effect on endogenous ABA and GA3 content. There were important differences among monthly levels of ABA, GA3, IAA, and Z. In the first year, IAA and Z content in shoot tips were higher than that of in the second year, whereas ABA level was lower in the first year. GA3 was not changed in both years. Results show that planting density, pruning style, and monthly and yearly changes in endogenous level of hormones in shoot tips play significant effect on phenological development and flowering in ‘Gemlik olive’ cultivar. High planting density reduced juvenility period and induced flower formation in olive.

Planting Density Interferes with Strawberry Production Efficiency in Southern Brazil

In the search for more efficient production systems, many changes have occurred in the strawberry production sector. Planting density is one of the management techniques that most interferes with the quality of fruits and production aspects. This study aimed to evaluate the effect of different planting densities on the photosynthetic characteristics, fruit quality, and production of the strawberry cultivar Pircinque. The study was conducted in the 2018/2019 and 2019/2020 harvests in Lages, Santa Catarina, Brazil. The treatments consisted of plant spacing of 5, 10, 15, 20, 25, and 30 cm. The experimental design was in randomized blocks, with four blocks and plots of 20 plants. Plant spacing interfered with fruit quality, photosynthetic efficiency, production, productivity, and economic return. Due to the fruits of Pircinque having a higher quality than other cultivars, the planting spacing between 5 and 15 cm allows meeting the fruit’s main production and quality requirements. However, it is up to the producer to adapt the management if opting for higher planting densities, which allow for a greater economic viability of the business.

Effects of Different Planting Densities on Photosynthesis in Maize Determined via Prompt Fluorescence, Delayed Fluorescence and P700 Signals.

The mutual shading among individual field-grown maize plants resulting from high planting density inevitably reduces leaf photosynthesis, while regulating the photosynthetic transport chain has a strong impact on photosynthesis. However, the effect of high planting density on the photosynthetic electron transport chain in maize currently remains unclear. In this study, we simultaneously measured prompt chlorophyll a fluorescence (PF), modulated 820 nm reflection (MR) and delayed chlorophyll a fluorescence (DF) in order to investigate the effect of high planting density on the photosynthetic electron transport chain in two maize hybrids widely grown in China. PF transients demonstrated a gradual reduction in their signal amplitude with increasing planting density. In addition, high planting density induced positive J-step and G-bands of the PF transients, reduced the values of PF parameters PIABS, RC/CSO, TRO/ABS, ETO/TRO and REO/ETO, and enhanced ABS/RC and N. MR kinetics showed an increase of their lowest point with increasing high planting density, and thus the values of MR parameters VPSI and VPSII-PSI were reduced. The shapes of DF induction and decay curves were changed by high planting density. In addition, high planting density reduced the values of DF parameters I1, I2, L1 and L2, and enhanced I2/I1. These results suggested that high planting density caused harm on multiple components of maize photosynthetic electron transport chain, including an inactivation of PSII RCs, a blocked electron transfer between QA and QB, a reduction in PSI oxidation and re-reduction activities, and an impaired PSI acceptor side. Moreover, a comparison between PSII and PSI activities demonstrated the greater effect of plant density on the former.