Specific Leaf Weight Research Articles

Abscisic acid induced cellular responses of sub1A QTL to aluminium toxicity in rice (Oryza sativa L.)

Involvement of abscisic acid (ABA) was studied for aluminium (Al) sensitivity through functioning of sub1A quantitative trait loci in rice cultivars. sub1A quantitative trait loci bearing cv. Swarna Sub1 was found almost compatible with non sub1A quantitative trait loci bearing cv. Swarna for abscisic acid accumulation all through the aluminium concentrations. However, abscisic acid was self inductive by over expression of its biosynthetic gene in nine-cis-epoxycarotenoid dioxygenase 3 (NCED3) more in cv. Swarna than other. The effect of abscisic acid pretreatment was variable for specific leaf weight, leaf mass ratio and others for the cultivars. Bio-accumulation of aluminium had revealed the sensitivity of toxicity more in cv. Swarna than other. In connection to oxidative stress generation of reactive oxygen species was detected by both histochemical and in vitro assays through hematoxylin, Evans blue and schiff's reactions. Abscisic acid pretreatment had significantly reversed the effects of aluminium toxicity for reactive oxygen species generation. Regardless of varieties sensitivity of aluminium was more prone in shoot than root as detected by nitro blue tetrazolium and 3,3′-diaminobenzidine mediated signalling. Activity in metal chelation in extra cellular spaces monitored through esterase activity and that also established independence of abscisic acid pretreatment for cv. Swarna Sub1. The specific polymorphism of esterase at protein level strengthened the bio-monitoring of aluminium through the rice varieties as well its modulation with abscisic acid. Abscisic acid has been discussed an important effectors to modulate the tolerance pathway of rice cultivars through intrusion of sub1A quantitative trait loci.

Growth and chlorophyll indices in seedlings of Calotropis procera (Aiton) W. T. Aiton submitted to different levels of shading

Several abiotic factors may influence the growth and development of forest species. Among these, luminosity is one of the most important, because it affects plant physiological processes and control their metabolism. The objective of this study was to evaluate the effect of different shading levels under growth
 and chlorophyll indices on Calotropis procera plants. The experiment was conducted in a greenhouse in a completely randomized design with 5 treatments (0, 30, 50, 70 and 90% of shading), 8 replicates and one plant per plot. Growth characteristics (leaf area, leaf area index, specific leaf area, leaf area ratio and leaf specific weight) and chlorophyll a, b, total index and chlorophyll a/b ratio were evaluated. The data were submitted to analysis of variance by the F test and in the cases of significance a linear and polynomial regression analysis was performed. Shade levels in the 40% range provide higher leaf area and leaf area
 index in silk flower plants. The specific leaf area and the leaf area ratio are positively influenced by shading. In shaded environments silk flower plants have reduced chlorophyll indices.

Effects of Weed on Growth of Several Soybean Cultivar

Soybean is one of the food commodities, which contains vegetable protein, carbohydrates and fat, hence it is necessary to complement the nutrition. Demand consumption of soybean higher with increasing population annually, the production of soybean is still sufficient to complete the increasing of demand. Therefore, the increasing of soybean production has to be considered to decrease the dependency on imported. Soybean production can be increased by the cultivation technique. In this method, the present of weed should be concerned. Weed can reduce the quality and quantity of soybean. The research was done at Kebun Pendidikan, Penelitian dan Pengembangan Pertanian (KP4) Gadjah Mada University which located at Kalitirto, Berbah, Sleman, Yogyakarta, Indonesia. This research started on November 2015-April 2016. The research aims to identify the effects of weed on the growth analysis of several soybean cultivar. This field research is arranged using spit plot with three blocks as the repetition where the main-plot is the weed treatments and those are weed-free, weeding in a critical period, and weedy. Sub plot is the soybean cultivars which are Anjasmoro, Argomulyo, Burangrang, Gema, Gepak Kuning, Kaba, and Wilis. The research’s result show the weed treatments would effect no significant difference in the leaf area index, net assimilation rate, crop growth rate (3 to 6 weeks after planted/WAP), specific leaf weight, and leaf area ratio (3 WAP). Which affects are the crop growth rate (6 to 9 WAP) and leaf area ratio (6 and 9 WAP)

Dry matter partitioning and K distribution of vegetable soybean genotypes with higher potassium efficiency

ABSTRACTField and pot experiments were conducted to select and identify the characteristics of potassium (K) high efficiency vegetable soybean genotypes. Forty genotypes under two potassium application levels (0, 120 kg ha−1 K2SO4) showed variations in K concentration, K accumulation, K internal use efficiency (KIUE) and K harvest index (KHI) in field experiment conducted in 2016. According to the distinct KIUE for yield (KIUE-Y) and KHI, two K high efficiency (KHE) genotypes (T117, L113) and two K low efficiency (KLE) genotypes (DZ1, ZX8) were used in pot experiment with two K levels (0, 120 kg ha−1 K2SO4) in 2017 for further investigation. Results indicated that KIUE-Y was significantly correlated with harvest index (HI) and KHI. Both K and dry matter (DW) were optimally distributed in the seed of KHE genotypes. In contrast, more DW and K were accumulated in vegetative organs of KLE genotypes, which was the main reason limiting K efficiency. Under K deficiency, KHE genotypes better regulate their DW and K distribution, and have higher specific leaf weight with unaffected leaf area.

‘Lemonato’ peach: a series of cultivated clones with high fruit quality

The ‘Lemonato’ peach is a series of clones cultivated in Magnesia, central Greece. These clones were selected locally from seedling populations characterized by different time of ripening and different fruit quality traits. The fruit are phenotypically discriminated from the other peach cultivars, as they have typical yellow skin colour when ripe, very little red hue and unique flavor and taste. The scope of the present work was the description of this series of clones based on morphological and agronomic characteristics, and fruit quality traits. Five trees of each ‘Lemonato’ clone in different locations throughout the cultivation area were selected based on ripening time. Presence of major stone fruit viruses was tested for each tree. For the morphological description of each clone, flowering time, shoot and fruit growth were followed in the field and shoots and fruit were described by UPOV. Specific leaf weight and leaf chlorophyll concentration were measured in late August. Fruit quality traits were also studied including fruit mass, skin colour, fruit firmness, soluble solids content, titratable acidity, total phenols and antioxidant activity. The results showed significant variation per clone and orchard for physiological leaf characteristics, shoot development, blooming and maturation time and fruit quality. We were able to separate trees with the best characteristics from each clone to initiate organized propagation, and, in the near future, to establish virus-free basic propagation material for each selection with different ripening times, to set up experimental farms and to exploit useful genetic traits through breeding programmes. These data will help spread the cultivation of this indigenous fruit clone series.

PERTUMBUHAN DAN HASIL GALUR-GALUR F4 PADI RAWA PADA RAWA LEBAK

[GROWTH AND YIELD OF F4 SWAMP RICE LINES ON LINE SWAMP]. Growth and yield of swamp rice are depending on the plant ability to adapt in swampy agro-ecosystem which characterized by several limiting factors. This study was addressed to evaluate the growth and yield characteristics of six lines of swamp rice bred for the development of high-yielding rice varieties best suited for swamp land production. Evaluation was conducted in a pot experiment using UBPR2, UBPR3,UBPR6, UBPR7, UBPR9, and UBPR10 as planting materials. These lines were the F4 generation derived from crosses involving local Bengkulu swamp rice varieties. Observations were made on 13 plant characteristics, dry matter accumulation, leaf area ratio, specific leaf weight, net assimilation rate, plant height, productive tiller number, heading date, maturity date, panicle length, grain number per panicle, percent of filled grain, and plant yield (the grain weight per clump). The collected data were subjected to analysis of variance and least significant difference test at 5% level. Results indicated that all lines physiologically exhibited similar growth patterns, excepting the capability of accumulating dry matter at 40 dap. In this case, UBPR6 produced the highest dry matter accumulation (24.34 g). Based on the morphological performances, significant variations among the lines were observed on most of the observed characteristics, except on productive tiller number and panicle length UBPR10 was the line produced the tallest plant stature (160.72 cm), UBPR2 was the earliest flowering and maturing line (76,33 and 111 dap), whereas UBPR6 was the line produced the highest grain number per panicle (212,2), percent of filled grain (95%), and plant yield (82.50 g per clump).

Stability, correlation and path coefficient analysis for yield and quality traits in betelvine (Piper betle L.) genotypes under three different sets of conditions

Betelvine (Piper betle L.) is commonly consumed as betel quid or paan with areca nut and/or tobacco; and also utilized in Indian medicine systems and in religious ceremonies. The betel production is highly erratic and so is the income of farmers due to natural climatic factors and spoilage during transport. It is therefore important to improve its productivity per vine and per unit area to meet the demand. Correlation, path coefficient and stability analysis was carried out in fifteen genotypes of betelvine including 3 checks under three protected structures, namely, Bareja (E1), Poly tunnel (E2) and Net tunnel (E3). Among the three structures, Net tunnel was found suitable for the cultivation of betelvine in Chhattisgarh. With respect to quality parameters, Meetha paan (2.65 g/100g) followed by Billori (2.23 g/100g) found to have high protein content. Meetha paan (5.89g/100g) followed by Meetha-cum-bangla (5.36g/100g) was also found to possess high starch content. However, low fiber content was recorded in Meetha pan (1.83g/100g), whereas high potassium content was found in Ramtake meetha (933mg/100g) followed by Bidhan pan (991mg/100g). The genotype, Karapaku possessed high potassium content (2.67mg/g). Hedonic five point scale for organolaptic test showed Meetha paan (2.3/5) followed by Bali paan (2.4/5) were less pungent among genotype studied. Highest shelf life was found in genotype Karapaku and Bhaichigudi (18days). The results indicated that number of leaves per vein were positively correlated with leaf width (0.802 and 0.819) followed by leaf area (0.790 and 0.808), leaf area index (0.782 and 0.800), leaf length (0.745 and 0.759), specific leaf weight (0.681 and 0.709), petiole length (0.658 and 0.705), diameter of internodes (0.484 and 0.559) and R-value (0.112 and 0.110) at both phenotypic and genotypic level, respectively. Path analysis identified leaf width (0.8772) and leaf length (0.4712) had direct effects on leaf yield at phenotypic level. Highest positive direct effect on leaf yield was exerted by leaf area (1.3544) followed by leaf width (0.8986) at genotypic level. These characters can be used as selection criterion in a breeding programme to develop varieties of betelvine with high leaf yield. The stability analysis under three different protected structures viz; E1, E2, E3 indicated that the genotypes, Karapaku, Bhaichigudi and Maghai pan are stable across the environment for leaf yield.

Growing spinach (Spinacia oleracea) with different seawater concentrations: Effects on fresh, boiled and steamed leaves

Agriculture is the human activity requiring the higher amount of freshwater. Nevertheless, water availability is already an issue in many regions of the world, suggesting the need of alternative water sources to face the increasing food demand. Spinacia oleracea plants have been cultivated in a floating hydroponic system where nutrient solution was integrated with 10% and 20% of seawater. Plant growth was monitored during the experiment together with morphological adaptations at the shoot level. At the end of the crop cycle, leaves were collected and processed with the two most common cooking processes such as boiling and steaming. Raw, boiled and steamed leaves were then analyzed to determine their sodium and potassium concentrations, the total phenolic content and the nitrates concentration. Our results showed that the use of seawater in the hydroponic spinach cultivation determined positive effects on growth parameters, with an increased relative growth rate assessed for both seawater treatments compared to the control. Leaves morphological adaptations were assessed only in 20% seawater treated plants (i.e. reduced leaf water content, leaf area and specific leaf area; increased specific leaf weight and leaf succulence), whereas the moderate seawater treatment did not lead to any difference compared to the control. Seawater treatments significantly increased sodium content in leaves, which could be consumed without adding any salt. Potassium was not affected by salinity treatments, whereas both total phenolic content and nitrates decreased accordingly with increasing salinity Concerning the cooking processes, steaming proved to be a better cooking method compared to boiling with the aim of preserving the nutritional values of spinach leaves. In conclusion, our results suggest that the use of a certain level of seawater in the spinach cultivation is a practical possibility to be explored in the direction of saving freshwater and increasing crop production enhancing the quality and taste of vegetables.

Supplementary Light Source Affects Growth, Metabolism, and Physiology of Adenophora triphylla (Thunb.) A.DC. Seedlings.

Adenophora triphylla (Thunb.) A.DC., a well-known herbaceous medicinal species, has been reported to protect against human obesity, cancer, and inflammation. Supplementary lighting is a practical strategy to improve crop quality, especially at a propagation stage. However, there has been no study available on the optimal supplementary light source for the commercial production of A. triphylla seedlings. In this study, plug seedlings were cultivated in a greenhouse for four weeks under an average daily light intensity of 490 μmol·m−2·s−1 PPFD coming from the sun and a supplemental lighting (16 h per day) at 120 μmol·m−2·s−1 PPFD provided by high pressure sodium (HPS), metal halide (MH), far-red (FR) light, white LED (red: green: blue = 2:4:3, LED-w), or mixed (red: green: blue = 4:1:4) LED (LED-mix). The results showed that LED-mix, with a higher percentage of red and blue light, substantially promoted seedling growth compared to other treatments by increasing stem diameter, biomass, specific leaf weight, and root to shoot ratio. The LED-mix also promoted accumulation of soluble sugar, starch, and chlorophyll in the tissue and increased contents of total phenols and flavonoids. Moreover, stomata density and pore area per leaf area under the LED-mix were remarkably greater than those under other treatments. Furthermore, the Western blot analysis revealed that the expression of photosynthetic protein, D1, was notably enhanced by the LED-mix as compared with other light sources. In addition, the LED-mix alleviated the oxidative damage of seedlings by improving enzymatic and nonenzymatic antioxidant systems. Collectively, these results suggest that the LED-mix was the optimal supplementary light source for the production of highest quality A. triphylla seedlings.

Interaction effect of nitrogen form and planting density on plant growth and nutrient uptake in maize seedlings

High planting density is essential to increasing maize grain yield. However, single plants suffer from insufficient light under high planting density. Ammonium (NH4+) assimilation consumes less energy converted from radiation than nitrate (NO3−). It is hypothesized that a mixed NO3−/NH4+ supply is more important to improving plant growth and population productivity under high vs. low planting density. Maize plants were grown under hydroponic conditions at two planting densities (low density: 208 plants m−2 and high density: 667 plants m−2) and three nitrogen forms (nitrate only, 75/25NO3−/NH4+ and ammonium only). A significant interaction effect was found between planting density and N form on plant biomass. Compared to nitrate only, 75/25NO3−/NH4+ increased per-plant biomass by 44% under low density, but by 81% under high density. Treatment with 75/25NO3−/NH4+ increased plant ATP, photosynthetic rate, and carbon amount per plant by 31, 7, and 44% under low density, respectively, but by 51, 23, and 95% under high density. Accordingly, carbon level per plant under 75/25NO3−/NH4+ was improved, which increased leaf area, specific leaf weight and total root length, especially for high planting density, increased by 57, 17 and 63%, respectively. Furthermore, under low density, 75/25NO3−/NH4+ increased nitrogen uptake rate, while under high density, 75/25NO3−/NH4+ increased nitrogen, phosphorus, copper and iron uptake rates. By increasing energy use efficiency, an optimum NO3−/NH4+ ratio can improve plant growth and nutrient uptake efficiency, especially under high planting density. In summary, an appropriate supply of NH4+ in addition to nitrate can greatly improve plant growth and promote population productivity of maize under high planting density, and therefore a mixed N form is recommended for high-yielding maize management in the field.

Photosynthetic characteristics of boll subtending leaves are substantially influenced by applied K to N ratio under the new planting model for cotton in the Yangtze River Valley

A new cotton planting model has been developed for the Yangtze River Valley which involves late sowing, high plant density and less applied N compared with the traditional transplanted cotton production. However, it is unknown if the K application rate can be reduced to achieve a 1:1 or lower applied K2O: N ratio. Therefore, we conducted field experiments to investigate the optimal K2O: N ratio for cotton under the new planting model. The study involved the evaluation of the photosynthetic attributes of the boll subtending leaves in relation to crop yield. A two-year (2016-17) field experiment was conducted with three K to N ratios [K08 (0.8:1), K10 (1.0:1) and K12 (1.2:1)] with 210 kg N ha−1 applied to all treatments. Our results indicated that the increased K application improved the photosynthetic attributes of the boll subtending leaves, leading to increased crop yield. Compared with K08, K10 and K12, respectively, enhanced the photosynthetic rate by 7–32% and 36–59%, chlorophyll fluorescence by 4–13% and 8–35%, chlorophyll content by 5–61% and 20–75%, total Rubisco activity by 7–23% and 30–55%, leaf area by 21–72% and 32–87%, leaf biomass by 12–36% and 31–51%, and relative water content of the boll subtending leaves by 2–8% and 13–16%. Also, compared with K08, leaf ATP content and SLW (specific leaf weight) were down-regulated in K10 and K12 by 7–23% and 1–26%, respectively. Moreover, statistically similar contribution to yield was found between K10 and K12, suggesting that under the late sowing, high density and low applied N model, a 1:1 K2O: N application rate N (K10) is the optimal choice for maximum financial return without reducing cotton yield.

Evaluation of agronomic performances of rainfed barley double-haploids (DHs) lines under semi-arid conditions

Abstract. Karkour L, Fenni M, Ramla D, Gaad D, Benbelkacem A. 2019. Evaluation of agronomic performances of rainfed barley double-haploids (DHs) lines under semi-arid conditions. Biodiversitas 20: 1398-1408. Sixty-six doubled-haploid (DHs) barley lines derived from F2 plants of three bi-parental single crosses, between the local variety (Tichdrett) and three introduced genotypes (Express, Plaisant, and Exito) were evaluated in 2017 for agronomic performance. The experiment was undertaken at two locations under rainfed conditions in semi-arid zone of Algeria in a randomized block design with three replications. Each line was scored for fifteen quantitative traits: number of days to heading, thousand grains weight, number of grains per spike, spikes number per m2, plant height, spike length, leaf relative water content, awn length, peduncle length, spike weight, grain weight per spike, leaf area, specific leaf weight, grain yield and harvest index. The results indicated that the presence of highly significant genotype effect for all traits except for leaf area and highly significant environment effect for all characters, except spikes number per m2and awns length. Genotype x environment interaction was highly significant for all traits, except specific leaf weight and leaf area. Significant positive correlation between the twelve agronomic traits, ranging from 0.45 to 0.87, were observed among the number of grains per spike, thousand grains weight, the number of spikes per m2, yield of grains and harvest index. The principal component analysis showed that four components could describe 72% of total variances. Cluster analysis divided all genotypes studied into three cluster groups. Overall, results of agronomic parameters and those related to the biotic and abiotic stresses will be used for better identifying this germplasm and better-directing studies of genetic improvement.

Identification of drought tolerant genotypes using physiological traits in soybean.

In plant breeding programs, screening for drought-tolerance is often a bottleneck. An experiment was conducted in the field and rainout shelters to: (1) identify physiological traits in breeding programs that can be used as criteria for selecting drought tolerance soybean genotypes [Glycine max (L.) Merr], (2) evaluate genotypic differences to drought tolerance, and (3) identify genotypes with superior drought tolerance. Sixteen genotypes were evaluated in split plot design under irrigated and drought conditions. Various physiological traits were measured in irrigated and drought stressed plants such as canopy temperature, root length, specific leaf weight, photosynthetic rate, chlorophyll, and epicuticular wax content. As compared with irrigated conditions, the percent reduction in mean soybean yield under rainout shelter was 40%. The mean yields of soybean genotypes ranged from 1162kg/ha (NRC 12) to 2610kg/ha (JS 335) under irrigated conditions, whereas, under water stress conditions, yields ranged from 852kg/ha (Samrat) to 1654kg/ha (EC 538828). Genotypes EC 538828, JS 97-52, EC 456548, and EC 602288 had better avoidance to drought than other genotypes. The superior drought tolerance of the four genotypes was related to their low canopy temperature, deep root system, and high values for root/shoot weight ratio, specific leaf weight, chlorophyll content, photosynthetic rate, epicuticular wax content, and Photosystem II (PSII) efficiency. Therefore, when genetic diversity of these physiological traits is established in breeding programs, these traits can be used as a selection criterion for selecting drought tolerant genotypes.

Dynamic Responses of Ascorbate Pool and Metabolism in Lettuce to Long-term Continuous Light Provided by Red and Blue LEDs

To understand the dynamic changes of lettuce growth, ascorbate pool and metabolism under long-term red and blue continuous light (CL, 24/0 h, 200 μmol·m−2·s−1), growth parameters, ascorbate pool size, as well as activities and gene expression levels of key enzymes involved in the ascorbate metabolism in lettuce leaves were investigated every 3 days during 15 days. In comparison with normal photoperiod (Control, 16/8 h, 200 μmol·m−2·s−1), lettuce plants gained greater shoot fresh weight and dry matter under CL, which depended more on specific leaf weight than leaf area. Both reduced ascorbate (AsA) and dehydroascorbate (DHA) contents were remarkably enhanced by CL and keep a relatively stable level during the experiment. The consistent greater contents of AsA and DHA were respectively attributed to the up-regulation of L-galactono-1,4-lactone dehydrogenase and ascorbate peroxidase activity rather than their gene expression. Although glutathione contents and glutathione reductase activities were elevated by CL, their contribution to AsA regeneration was limited on account of similar activity and expression level of dehydroascorbate reductase with control. In addition, H2O2 content was also raised obviously under CL compared with control, but it was maintained at a relative safety and stable level from day 6. Fluorescence imaging results also showed that CL did not induce oxidative damage on lettuce leaves compared with control. It is concluded that lettuce plants grown under red and blue continuous light for 15 days obtained greater shoot biomass and ascorbate pool size without leaf injury, and 9 days was the most cost-effective duration for yield improvement from an energy standpoint. Ascorbate accumulation under continuous light was primarily and rapidly regulated by the enzymes involved in AsA biosynthesis and oxidation at enzymatic activity level rather than gene expression level.

The Growth and Development of ‘Mini Chal’ Tomato Plug Seedlings Grown under Various Wavelengths Using Light Emitting Diodes

This study aimed to determine the effects of various light qualities (green (G), ultraviolet-A (UV-A), and far-red (Fr)) on the growth and development of tomato plug seedlings. The ‘Mini Chal’ tomato (Solanum lycopersicum L.) seedlings were used as the plant material to which various light qualities were supplied. Fluorescent lamp (FL), combined FL and diniconazole (Dini), and R3B7 (red (R):blue (B) = 30:70) were used as the control. The different light treatments for this experiment were as follows: two G light ratios added to R3B7 (G20 and G40), three UV-A light intensities added to R3B7 (UV 0.4, UV 0.6, and UV 0.8), and three Fr light ratios added to R3B7 (Fr1, Fr2, and Fr3). Plants grown in UV 0.4 and Dini were the shortest, followed by plants grown in R3B7. R3B7 induced higher specific leaf weight than G, UV-A, and Fr did. The position of the first flower cluster was the highest for plants in FL and Fr1, and the lowest for plants in R3B7 and UV 0.6. In conclusion, different light treatments heavily affected the growth and development of ‘Mini Chal’ tomato seedlings. R3B7 was the most effective light treatment for producing high quality seedlings in a closed-type plant production system that develop well after transplanting.

Magnetopriming regulates antioxidant defense system in soybean against salt stress

Abstract The field experiment was conducted to study the influence of magnetopriming with static magnetic field (SMF of 200 mT for 1 h) on growth, nitrogen fixation, photosynthesis, antioxidative system and yield of soybean under salt stress. The results revealed the adverse effect of salinity on growth, photosynthesis, nitrogenase activity and yield. Salt stress significantly elevated the level of hydrogen peroxide (H2O2) and ascorbic acid (ASA) and the activities of superoxide dismutase (SOD), ascorbic acid peroxidase (APX), glutathione reductase (GR) and guaiacol peroxidase (POD) in leaves of soybean seedlings emerged from unprimed seeds. However, α-tocopherol content was reduced with the increase concentration of NaCl but it was enhanced in leaves emerged from magnetoprimed seeds. On the other hand leaf area, specific leaf weight, photosynthesis, nitrogenase activity and ASA/DHA ratio were significantly increased whereas H2O2, ASA and antioxidant enzymes were reduced significantly by SMF pre-treatment; which ultimately improved the biomass accumulation, yield and harvest index of soybean under both the saline and non saline conditions. These results indicated that SMF pre-treatment compensated for the negative effects of salinity stress, consequently soybean plants do not have to deflect their metabolic energy in detoxification of ROS produced under salt stress. Thus application of magneto-priming could scavenge or alleviates the harmful effects of salinity stress at the field performance of soybean plants and it can be used in agriculture to better growth and increased yield under adverse abiotic stress conditions.

Effects of changing frequency of fluctuating light on photosynthesis in cucumber seedlings

Plants are often exposed to fluctuating light under natural conditions, but the effects of changing frequency of fluctuating light on photosynthesis and related mechanism are not clear. In order to study the photosynthetic mechanism under fluctuating light, the changes of morphology, chlorophyll content, gas exchange, chlorophyll a fluorescence and enzymatic antioxidant system were compared in cucumber seedlings grown under different light regimes. Results showed that the plant height, biomass, leaf area and specific leaf weight were significantly higher under high light treatment (T1, T2 and T3) than those of low light treatment (T4), and these values decreased with the frequency of fluctuating light increasing (T2 and T3). Compared with low light treatment, the total chlorophyll content decreased under high light, and enhancing the frequency of fluctuating light resulted in the decrease in the chlorophyll content slightly. Photosynthetic rate and stomatal conductance in leaves grown under high light were higher than those under low light, and the levels of both parameters decreased slightly with the changing frequency of fluctuating light increasing. The results of chlorophyll a fluorescence induction kinetics showed that although there was no significant difference in the maximum quantum yield of photosystem II (PSII), the electron transport activity of PSII in cucumber leaves decreased with the increase of the changing frequency of fluctuating light. Increasing the changing frequency of fluctuating light led to an obvious decrease in antenna conversion efficiency of PSII ( F v′/ F m′) and rapid increase in non-photochemical quenching (NPQ). In addition, the activities of the major antioxidant enzymes in cucumber leaves grown under high light was higher than that under low light, yet the increase of the frequency of fluctuating light reduced their activities. Therefore, enhancing the changing frequency of fluctuating light leads to a decrease in photosynthetic rate and the activities of major antioxidant enzymes in cucumber seedlings, the enhanced thermal dissipation may play a very important role in copying with excessive excited energy under fluctuating light. In addition, the difference in acclimative mechanism between fluctuating and steady-state high light in cucumber seedlings were also discussed.

Effect of chemicals, PGRs and pruning on morpho-physiological parameters in mango under high density planting

Investigations on the effect of canopy management in mango (Mangifera indica L) cv Alphonso using chemicals, different growth regulators and pruning methods under high density planting were conducted during 2015–2016. The treatments were evaluated in terms of changes in morpho-physiological attributes. Among eight treatments, soil drenching of paclobutrazol registered the lowest canopy diameter and length and highest girth of shoots. The chlorophyll a, b and total chlorophyll contents and SPAD value of the leaves were significantly improved by the application of growth retardants particularly paclobutrazol and chlormequat chloride. Specific leaf weight was markedly improved by the application of growth retardants. Statistically superior soluble protein content and maximum level of total phenolics were observed in paclobutrazol applied trees followed by triple spray of chlormequat chloride at pre-flowering stage (Dec 2015).

Impact of irrigation with saline water on morphology of sea buckthorn seedlings in nursery

The experiment for evaluate the effect of salinity stress on the morphological behaviors of Elaeagnus rhamnoides (L.) A. Nelson seedlings were done in Torogh nursery in Iran country. This species were conducted based on completely randomized design in summer season. Non-stress (EC 0.8 dSm-1) and salt treatment (EC 12.03dS m-1) were used every two days. Several morphological traits of seedlings stressed-including height, diameter, leaf number, leaf area, shoot and root length, freshly and number of root, fresh and dry weight of stem, root and leaf and ratio of root to shoot, leaf to shoot, leaf area, specific leaf area, leaf weight and slenderness index were determined analyzed. Results indicated that diameter growth, end of period height, height mean and leaf area growth were significantly different at p<0.05 level and height growth and number of leaves reduced significantly at p<0.01 in comparison with control treatment. Analysis of variance for nonlinear regression in salinity stress indicated in the height and diameter significant differences of p<0.01 and leaf number not significant differences. Principal component analysis showed that in first axis (PC1) in salinity treatment dry weights leaf, stem and root, leaf area, root to shoot ratio, freshly, leaf area ratio decrease and were the most correlated with first axis. Thus, not recommend that to be done irrigation with EC 12.03 dS m-1.

Strengthening soil health under rice (Oryza sativa) fallows in Eastern Plateau of India with dwarf rice and moisture conservation practices

There is great scope in converting rice (Oryza sativa L.) fallows into productive agro-ecosystems through appropriate crop based interventions involving suitable varieties and appropriate resource conservation technologies (RCTs). Pulses such as chickpea, lentil, lathyrus and blackgram -through rotation or relay with rice - are the candidate crops for efficient utilization of conserved and scarce resources including soil moisture. Therefore, studying bio-physical aspects of popular rice - chickpea rotation so as to conserve resources and deriving maximum benefits is important and is the crux of the current investigation. A study was carried out in a vertisols at Indira Gandhi Krishi Vishwavidyalaya, Raipur (India) during 2011-14 under the existing conditions guarded by a tropical sub-humid climate receiving an annual precipitation of 1582 mm. Two transplanted rice habit groups (a tall local rice Masuri, maturing at 130-140 days and a dwarf HYV of rice Swarna, with 110-120 days duration grown during rainy season) were combined with three residue management practices, viz. residue removal, stubble (30 cm) and mulch for growing two contrasting varieties of chickpea (early high biomass JG 130 and medium high biomass JG 226) grown during winter season. Chickpea was planted with a zero till drill after rice. The study showed that soil moisture depletion (SMD) pattern was decreased over the crop season in case of mulched or 30 cm stubble retained plots in comparison to absence of mulch due to its possible role as a soil cover. On the contrary, SMD was higher in case of tall rice (Masuri) habit due to its relatively longer duration as compared to dwarf rice (Swarna) habit. Similar although to a lower degree in SMD was apparent in case of early biomass accumulating variety (BAV) chickpea JG 130 over medium BAV JG 226. Soil health parameters in terms of its physical and microbiological parameters (like, bulk density, soil strength, dehydrogenase activity etc), crop physiological parameters (such as relative leaf water content (LWC) and specific leaf weight (SLW), plant population), nodulation activities (Rhizobium population, nodule number and its dry weights) and crop growth/yield parameters (pods/plant, root characteristics etc) were positively influenced by mulch or stubble retention (due to its beneficial role as a soil cover) and dwarf rice habit (Swarna). Small yet consistently superior values of soil fertility indicators, viz. soil organic carbon (SOC) and nutrients (NPKZn, Fe, Mn and Cu) availability status were also evident following mulch or retention of stubble on the soil surface, whereas the values were abysmally small when comparison was made between chickpea cultivars (early BAV JG 130 and medium BAV JG 226). Besides these, weed dynamics, grain yield attributes and the resultant grain yield were especially favoured following soil moisture conservation strategies involving dwarf rice habit and mulch/stubble retention since availability of soil moisture was fairly extended over a period of time following these measures. Thus, it is inferred from the study on rice-chickpea system that efficient agronomic management of soil and land resources is crucial for augmenting soil health and enhancing output in prevalent rice fallow of Eastern Indian Plateau.