Dry Matter Distribution Research Articles

Effect of nutrient application on dry matter accumulation and translocation of early rice

Plot experiments were set up with rice cultivar Xiangzaoxian45 in Yiyang and Xiangyin to investigate the effects of different nutrient application on dry matter accumulation and distribution in early rice.Six treatments were used in each experiment including T1(fertilization application without nitrogen),T2(conventional fertilization application used by farmers),T3(fertilization application for high yield and high efficiency),T4(fertilization application for super high yield),T5(fertilization application for super high yield and high efficiency A) and T6(fertilization application for super high yield and high efficiency B).The results showed that dry matter accumulation after heading stage in Yiyang and Xiangyin with T3 increased by 43.55% and 18.85%,respectively and the corresponding yield of early rice increased by 4.20% and 4.80%,respectively,compared to T2 under the condition of saving 20% nitrogen fertilizer.In the experiment conducted in Yiyang,dry matter accumulation after heading stage and yield of early rice with T5 increased by 80.85% and 16.60% respectively,with T6 increased by 94.00% and 18.75%,respectively,compared to those with T2;and in Xiangyin,dry matter accumulation after heading stage and yield of early rice with T5 increased by 23.64% and 10.10%,respectively,with T6 increased by 22.91% and 6.75% respectively,compared to those with T2.There was an extremely significant correlation between yield and dry matter accumulation after heading stage at different soil fertility levels.Therefore it is an important way to increase the accumulation of dry matter after heading stage for improving the yield of early rice.

Effects of Nitrogen Application Depth on Water Consumption Characteristics and Dry Matter Accumulation and Distribution in Rainfed Wheat

To raise a suitable nitrogen application depth for rain-fed wheat in the Yellow-Huai Rivers Zone in China,we tested the water consumption characteristics and dry matter accumulation amounts and distribution ratios of wheat cultivars Shannong 16 and Yannong 0428 under different nitrogen application depths in 2010-2011 and 2011-2012 growing seasons.The nitrogen application depths were designed in four levels,which were surface application(D1) and application depths of 10 cm(D2),20 cm(D3),and 30 cm(D4).Compared to D1 and D2,D3 and D4 exhibited significantly greater water consumption amounts in the periods of jointing-anthesis and anthesis-maturity and soil water consumption amounts in 40-120 cm soil layers(P 0.05).In the 2011-2012 growing season with sufficient precipitation,the 120-160 cm soil water consumption amounts of D3 and D4 treatments were 4.0-5.3 mm greater than those of D1 and D2(P 0.05).These results indicated that nitrogen applied in 20-30 cm of soil depth could increase the utilization of soil water,particularly deep soil water,to meet the water requirement of wheat plant after jointing stage.Besides,D3 and D4 treatments also showed dramatically higher dry matter accumulation amounts from jointing to maturity than D1 and D2 treatments(P 0.05).After anthesis,the dry matter accumulation amounts in D3 and D4 were 394.5-723.1 kg ha 1 higher than those in D1 and D2,and at maturity stage,the increments were 642.1-2006.8 kg ha 1.The grain yields and partial factor productivities of nitrogen in D3 and D4 were significantly higher than those in D3 and D4,and no significant difference between D3 and D4.Besides,D3 had relatively higher water use efficiency.Therefore,we suggest that 20 cm is the optimal soil depth of nitrogen fertilizer application for rain-fed wheat in Huang-Huai Rivers Zone.

Characteristics of Water Use and Dry Matter Accumulation and Distribution inDifferent High-yielding Wheat Cultivars under Supplemental Irrigation Basedon Soil Moisture

Water shortage is a serious problem threatening sustainable agricultural development in the North China Plain, where winter wheat(Triticum aestivum L.) is the largest water-consuming crop. The objective of this study was to guide wheat production in this area by selecting high water efficient cultivar and improving irrigation regime. In a two-year field experiment from autumn of 2007 to summer of 2009, irrigation quantum was controlled based on testing soil moisture(SM) in 0–140 cm depth,which was designed in low(SM of 65% at jointing and 55%–60% at anthesis stage), medium(SM of 75% at jointing and65%–70% at anthesis stage), and high(SM of 75% at jointing and 75% at anthesis stage) levels. Water use efficiency(WUE), dry matter accumulation and distribution in wheat plant, and grain yield were tested and compared among 14 commercial cultivars.Based on grain yield and WUE, the 14 cultivars were clustered into three groups, namely, super-high yield and high WUE group(I), super-high yield and medium WUE group(II), and high yield and low WUE group(III). One representative cultivar was selected from each group to compare the amount and proportion of water consumption during sowing–jointing, jointing–anthesis,and anthesis–maturity periods. Shannong 15 from group I had significantly lower water consumption from sowing to jointing than Jimai 22 from group II and Yannong 21 from group III, and significantly higher water consumption from jointing to anthesis.However, water consumption amount and proportion had no significant differences among the three cultivars from anthesis to maturity. Under medium SM condition, soil water consumption in Shannong 15 was significantly higher than that in Jimai 22 and Yannong 21, but such advantage in Shannong 15 disappeared under high SM condition. Under medium and high SM conditions,translocation amount and ratio of dry matter accumulated before anthesis and its contribution to grain were significantly higher in Shannong 15 than in Jimai 22 and Yannong 21. Among the three cultivars, harvest index was the highest in Shannong 15, the medium in Jimai 22, and the lowest in Yannong 21.

Green Bean under Organic and Integrated Crop Systems in a Mediterranean Area Greenhouse: Effects on Dry Matter and Nutrient-Extraction Distribution Pattern

The experiment was conducted in two polyethylene greenhouses located in Almería (Spain) with Mantra green bean crop (Phaseolus vulgaris ssp. volubilis), on a sand-mulched loam soil with trickle irrigation. The experimental design was two factorial with four replications per treatment. The treatments applied were two crop systems, organic (OCS) and integrated (ICS), and two organic-matter levels of soil, 1.0% (low organic-matter soil, LOMS) and 2.5% (high organic-matter soil, HOMS). Nitrogen (N) and potassium (K) were applied by fertigation, and total levels were 68 kg N ha−1 and 107 kg K ha−1 following Regulation (CEE) 2092/91 (Organic Crop System) and Specific Regulation of the Junta of Andalusia (Spain) BOJA 10/01(Green Bean Integrated Crop Production). Total N, phosphorus (P), K, calcium (Ca), and magnesium (Mg) were determined in different plant fractions (fruit, leaf, and stem). Nutrient extraction by plant was significantly greater under ICS (111 kg N ha−1, 36 kg P ha−1, 130 kg K ha−1, 96 kg Ca ha−1, and 30 kg Mg ha−1) than under OCS (78 kg N ha−1, 22 kg P ha−1, 83 kg K ha−1, 71 kg Ca ha−1, and 22 kg Mg ha−1). Extracted nutrient levels did not show significant differences between organic-matter treatments. Nutrient-use efficiency was similar under all treatments. Also the N and Ca patterns between organs were unaffected by treatments, but P, K, and Mg distribution patterns among organs were affected by treatments. In general, N fruit and leaf extractions were similar (around 40%) and greater than N stem. Phosphorus leaf extraction was greater than in stem and fruit. Calcium and Mg extractions were the greatest in leaf (70% and 50%), intermediate in stem (20% and 30%), and the lowest in fruit (10% and 20%). Potassium fruit extraction under ICS was significantly greater (39%) than OCS (35%), whereas K stem extraction under OCS was greater (40%). Similar distribution patterns were found for organic-matter level. Potassium fruit extraction under HOMS was greater, whereas K stem extraction was greater under LOMS.

Vertical distribution of dry mass in cereals straw and its loss during harvesting

Abstract The study aimed at evaluating the distribution of mass in the straw of cereal species and also at assessing the straw yield and its losses resulting from the amount of the stubble left in the field. It was found empirically that the wheat culms are composed of five internodes, and in barley, triticale and oats of six. The highest straw mass per 1 cm was found in the second internode in both forms of wheat and winter triticale, whereas barley and oats gathered the highest weight in the first internode. In the southern part of Silesia species and forms of cereals differed in the straw yield, which can be arranged as follows, from the highest: winter wheat > spring wheat, winter triticale, winter barley, and oats > spring barley. Due to the specific distribution of dry matter in each of internodes of both wheat forms - winter and spring, they loose less stubble mass (22 and 24%, respectively), comparing to other cereals, especially spring barley, which loose 31% yield of straw in the stubble of 15 cm height.

Dry matter production at different growth phases and its variability inCorchorus capsularisL.

Pattern of dry matter distribution within different plant parts in 15 genotypes of Corchorus capsularis jute was estimated. Significant differences for distribution of dry matter were observed. Linear increase in dry weight of root, leaf and stem was recorded following the progress of growth period in most of the genotypes. Consistent superiority with respect to dry matter production in root, leaf, stem and bark with high bark to stick ratio was shown by CEX 040. On the other hand, CEX 048 had highest dry seed and pod weight. CEX 040 and CEX 048 can be recommended for commercial production of fibre and seed respectively. Least environmental influence was observed in partitioning of dry matter. Various components for fibre yield was predominantly controlled by additive gene action and that for seed by both additive and non additive gene actions. Dry matter in bark showed significant positive correlations with that of root at 120 days, leaf at 60 days, stem at 90 and 120 days whereas seed weight showed similar relationship with pod weight, leaf dry weight at 90 days and stem dry weight at 60 and 90 days.

Crecimiento en plantas de fresa parcialmente defoliadas cultivadas en los altiplanos tropicales

Plants may undergo partial defoliation due to natural or accidental factors. The present study presents the results of an experiment to determine the effects of partial defoliation on the growth of strawberry plants (Fragaria × ananassa Duch. cv. ‘Chandler’) in Tunja, Colombia. Three defoliation levels were applied to plants after transplanting: 38% defoliation, 67% defoliation, and a control without defoliation. Water uptake, dry matter distribution among different plant organs, leaf area, and total dry weight were measured. Using this information it was possible to calculate leaf area ratio (LAR), leaf weight ratio (LWR), absolute and relative growth rates, and water use efficiency. All variables evaluated showed reduced values as a result of defoliation, which indicates that strawberry plants are sensitive to defoliation levels above 38% and show severely compromised growth as a result.

Effect of different organic manures on oil flax dry matter accumulation, distribution and yield

To realize oil flax(Linum usitatissimum Linn) high yield and good quality,field experiments were conducted in Baiyin and Lanzhou Cities of Gansu Province and Ordos City of Inner Mongolia Autonomous Region.The study compared the effects of the applications of four different fertilizers on oil flax dry matter accumulation and distribution and yield.The four fertilizers included farmyard manure(T3),oil flax residue(T4),and "Qingtiaobu"(T5) and "Woliheng"(T6) bio-fertilizers.Treatments without fertilizer(T1) and with chemical fertilizer(T2) were used as controls.The results showed similar trends in oil flax dry matter accumulation under all the fertilizer treatments in three different experiment sites with the order of T4 T2 T3 T6 T5 T1.Fitted logistic equations of oil flax dry matter accumulation in all the three sites were significant at P 0.01.The maximum rate of dry matter accumulation generally occurred at squaring stage,or at young fruit stage when planting date was delayed.Days for dry matter accumulation increasing with time in straight line and maximum accumulation rate in the three sites were in the order of T3 T2 T4 T5 T6 T1 and T4 T2 T3 T6 T5 T1,respectively.Dry matter distribution ratios of flowers and fruits at ripping stage under different organic fertilizer applications were higher than that under the controls.Pod number per plant,seed number per pod and thousand-grain weight of T4 were significantly(P 0.01) higher than those of the controls.Pod number per plant,seed number per pod and thousand-grain weight of T3 were higher than those of T2,but the differences were insignificant across the three experimental sites.Both T3 and T4 yields increased by 22.85%～45.40% and 62.83%～88.13% over treatments without fertilizer.Also yields of T5 and T6 increased by 15.14%～18.10% and 17.65%～21.01% over treatments without fertilizer.Yield of T4 significantly increased by 9.58%～39.49% over the treatment with chemical fertilizer.Yields of T5 and T6 significantly decreased by 14.63%～20.52% and 12.77%～18.57% over treatments with chemical fertilizer.Though yield of T3 decreased by 1.50%～8.91% over treatments with chemical fertilizer,the difference was not significant.Oil residue and farmyard manure were therefore the recommended fertilizers for enhanced development of organic production of oil flax.

Temporal variation in root penetration ability of wheat genotypes through thin wax layers in contrasting water regimes and in the field

A significant proportion of arable land in south-western Australia is highly susceptible to subsoil compaction, which limits access of roots of wheat to water and nutrients at depth. Australian wheat cultivars were shown to differ in penetration ability. The objective of this paper was to examine the dynamics of penetration ability and temporal variation in root growth using contrasting cultivars, with and without a thin wax layer, in contrasting water regimes, and in the field on two contrasting soil types at Merredin, Western Australia. The presence of a wax layer had a significant impact on root dry matter (DM) distribution and root number, which were more abundant above the wax layer. Root axes below the wax layer were around 50% shorter compared with columns without wax layers. Around 15% more nodal roots were produced in columns containing wax layers than those without and this difference was apparent from an early stage of plant growth, as was the impact of water deficit that decreased root DM and nodal root number above the wax layer. Root axes of genotypes Bonnie Rock, Castle Rock, Halberd and Spear all penetrated the wax layer, while CM18 and Cranbrook had limited or no success, regardless of water regime. The maximum root depths in field soils at 75 and 90 DAS were relatively shallow at 35–48cm, but with a relatively small variance. On a sandy duplex containing a hardpan, CM18 and Cranbrook had 28% shorter roots than Bonnie Rock and Halberd at 75 DAS, which was consistent with the poor ability of roots of CM18 and Cranbrook to penetrate wax layers. Adaptation of roots to soil physical constraint thus provides benefit for root access to deeper soil layers.

EFFECTS OF POD-ZONE CALCIUM SUPPLY ON DRY MATTER DISTRIBUTION AT MATURITY IN TWO GROUNDNUT CULTIVARS GROWN IN SOLUTION CULTURE

Dry matter (DM) partitioning to pods, vines and roots of groundnut at maturity was examined as a function of pod-zone calcium (Ca) supply (0–2500 μM) in a Virginia cv. Virginia bunch 1 (‘VB-1’) and Spanish cv. ‘TMV-2’ groundnut grown in a split root-zone/pod-zone solution culture system. The pod-zone Ca supply significantly affected growth and DM distribution of the two cultivars. The pattern of DM distribution of ‘VB-1’ differed considerably from that of ‘TMV-2’. At optimal pod-zone Ca supply, the DM partitioned to kernels in ‘VB-1’ was 11% of the total plant biomass compared with 32% in ‘TMV-2’. In both cultivars, the vine and root DM were negatively correlated with that in the pod. Total plant DM was also negatively correlated with pod DM in both cultivars, suggesting that the photosynthetic capacity of the groundnut plant is somehow compromised by pod filling.

Effects of EDTA, EDDS and Citric Acid on Growth of Maize and Uptake of Lead by Maize in Contaminated Soil

EDTA, EDDS and citric acid were added to moderate artificial contaminated soil to investigate the effects of the organic acids on growth of maize seedlings and phytoextraction of lead by maize. The results show that the effects of the organic acids on plant growth are different in Pb contaminated soil. The organic acids can change the dry matter distribution of the shoots and the roots and can increase the shoots biomass in most case. EDTA and EDDS can significantly increase the concentrations and uptake of Pb in the shoots of maize, indicate that EDDS is a potential phytoextraction intensifier in phytoremediation of Pb-contaminated soil.

Common ragweed (Ambrosia artemisiifolia) dry matter allocation and partitioning under different nitrogen and density levels

Dry matter partitioning and allocation is a major determinant of plant growth and its competitiveness. Common ragweed (Ambrosia artemisiifolia) is a troublesome agronomic weed species and it is also a major health concern in Europe and many other countries because of its rapid spreading and production of allergenic pollen. A field experiment was conducted in 2009 to determine the effect of nitrogen fertilizer levels (0, 100, and 200 kg ha−1) and plant density levels (1.3, 6.6, and 13.2 plants per m2) on the leaf, stem dry matter partitioning, and dry matter allocation of ragweed. With an increasing density, the stem partitioning coefficient increased, whereas the leaf partitioning coefficient decreased. The addition of nitrogen had a limited effect on the leaf and stem dry matter partitioning. The root dry matter production decreased with an increasing density and was not influenced by the addition of nitrogen. Under intraspecific competition, ragweed exhibited a stronger above‐ground competition intensity than below the ground, which resulted in a greater root : shoot ratio, compared to the low‐density stands. The level of nitrogen influenced the vertical leaf, stem, and total dry matter distribution, with a greater allocation to the top stratum of the plants, thus increasing their competition for light. The biomass allocation of ragweed to the roots in response to the nitrogen supply exhibited a low plasticity, compared to the shoots, which displayed a high plasticity. The results of this study suggested that, under intraspecific conditions and with an increasing nitrogen supply, ragweed would be more competitive in above‐ground resource acquisition.

Study on simulation models of tomato fruit quality related to cultivation environmental factors

Plant growth simulation models are valuable tools for optimizing the environmental factors and managing crop cultivation in cultural facilities. Researches presently on tomato simulation models have mainly focused on the plant growth and development, growth stages, dry matter production and distribution, however, no report on modeling of tomato fruit quality has been published yet. In this study, the method of accumulated Thermal Effectiveness and PAR (TEP) was employed to model the dynamic relationship between the major quality indicators and the environmental factors. Data of both indicators of tomato fruit quality and environmental factors, temperature and solar radiation of the cultivation environment, were collected under multiple protected structures like solar greenhouse and plastic tunnel for tomato production. The variety of simulation models were established based on the effects of temperature and solar radiation on tomato quality formation, and independently tested with the modeling data. The results show that the dynamic changes of the indicators of fruit quality after fruit set are accorded with the amount of accumulated TEP and individual indicators of fruit quality are suitable to its specific models. The fruit hardness is well accorded with a formula of generalized least squares FHi=k1+k2×TEPi+k3×TEPi2; Fruit soluble sugar content is in a formula of Logistic model SSCi=b11+eb2+b3×TEPi. Fruit organic acid content is in a formula of generalized least squares OACi=n1+n2×TEPi+n3×TEPi2. Fruit tannin content is in a formula of Johnson Schumacher model TCi=q1×e-q2TEPi+q3. According to the established fruit hardness model, the determination coefficient R2 values based on the 1:1 beeline between the simulated values and the measured values of the first, second, third and the fourth truss of fruit are 0.9396, 0.9181, 0.8910 and 0.9523, respectively and values of root mean square error (RMSE) are 0.833kg/cm2, 0.942kg/cm2, 0.628kg/cm2 and 0.738kg/cm2, respectively. Based on the established fruit soluble sugar content model, the determination coefficient R2 values based on the 1:1 beeline between the simulated values and the measured values of the first, second, third and the fourth truss of fruit are 0.8596, 0.9420, 0.9027 and 0.9473, respectively and the values of RMSE are 1.011%, 0.710%, 0.771% and 0.608%, respectively. On the basis of the established fruit organic acid content model, the determination coefficient R2 values based on the 1:1 beeline between the simulated values and the measured values of the first, second, third and the fourth truss of fruit are 0.8856, 0.9025, 0.9183 and 0.8768, respectively and the values of RMSE are 0.029%, 0.030%, 0.024% and 0.023%, respectively. According to the established fruit tannin content model, the determination coefficient R2 values based on the 1:1 beeline between the simulated values and the measured values of the first, second, third and the fourth truss of fruit are 0.9481, 0.9219, 0.9521 and 0.8911, respectively and the values of RMSE are 13.41mg/kg, 14.04mg/kg, 13.92mg/kg and 16.78mg/kg, respectively. All of the coefficients of determination R2 are higher than 0.85, and the values of RMSE are generally smaller, which means the modeling is accurate and well accordance. This study will form a theoretic basis and provide technical support for the management of tomato production and environment control under plastic tunnel and solar greenhouse cultivation.

Effects of grafting on potassium use efficiency of different cotton genotypes

采用全生育期土培盆栽试验, 在研究2个棉花基因型钾吸收效率和利用效率的基础上, 对未嫁接和经嫁接的自根苗(接穗和砧木为同一基因型)处理的棉花干物质和钾的积累、分配进行比较。结果表明: 自根苗植株与未嫁接植株相比, 不同棉花基因型在不同钾水平下干物质和钾的积累及分配不同。高效基因型103经过嫁接后营养器官中的干物质和钾比例增加, 生殖器官中的干物质和钾减少, 产量和钾利用指数下降; 低效基因型122经过嫁接后营养器官中的干物质和钾比例减少, 生殖器官中的干物质和钾增加, 产量和钾利用指数升高。吸收效率因钾水平而异, 高效基因型103嫁接后施钾时吸收效率降低, 缺钾时升高; 而低效基因型122嫁接后施钾时吸收效率升高, 缺钾时降低。嫁接对不同棉花基因型产生的效应不同, 通过嫁接使不同棉花基因型物质分配趋于平衡。

Short communication: Varying dietary dry matter concentration through water addition: Effect on nutrient intake and sorting of dairy cows in late lactation

The objective of this study was to determine if feed sorting can be reduced and if nutrient consumption can be limited in late-lactation cows through water addition to a nutrient-dense total mixed ration (TMR) with a dry matter (DM) content greater than 60%. Twelve lactating Holstein cows (214.8±28.5 d in milk) were exposed to 2 diets in a crossover design with 28-d periods. Diets had the same ingredient composition and differed only in DM percentage, which was reduced by the addition of water. Treatment diets were (1) dry TMR (61.7% DM) and (2) wet TMR (51.9% DM). Dry matter intake and milk production (4% fat-corrected milk; FCM) were recorded for the last 14 d of each treatment period. For the final 4 d of each period, fresh feed and orts were sampled for particle size analysis and subsequent calculation of sorting activity (expressed as a percentage of predicted intake). Adding water to the diet tended to decrease the amount of DM in the fine particle fraction, increase starch concentration in the longer ration particles, and reduce starch concentration in the shortest ration particles. All cows sorted against long ration particles; the extent of this sorting did not differ between the dry and wet treatments (72.9 vs. 77.6%). There tended to be more sorting for fine ration particles on the dry diet compared with the wet (106.3 vs. 104.0%). Water addition had no effect on production, with similar DMI (27.9 vs. 26.5 kg/d), 4% FCM (28.7 vs. 27.6 kg/d), and efficiency of production (0.98 vs. 1.00kg of 4% FCM/kg of DMI) between the dry and wet treatments. Adding water to a TMR with greater than 60% DM containing primarily haylage and corn silage forage sources may change ration particle DM distribution and particle starch content, possibly contributing to less sorting for the smallest ration particles. This research does not provide evidence that water addition to such a TMR can effectively limit DMI in late-lactation cows and, thus, improve efficiency of milk production.

Root length, root mass, and distribution of dry matter in different parts of Thompson Seedless grapevine grafted on different rootstocks in heavy soil of Maharashtra

The root distribution pattern of 3 grape rootstocks, Dog Ridge, Salt Creek, and St. George, grafted with Thompson Seedless grapevine was studied at the National Research Centre for Grapes in Pune, India. The soil is heavy black cotton soil (vertisol) with a pH of >8.0. Roots of different thicknesses (10 mm) were examined at horizontal distances of 0-30 cm, 31-60 cm, 61-90 cm, 91-120 cm, and 121-150 cm away from the trunk and also to depths of 0-30 cm, 31-60 cm, and 61-90 cm from the surface. Among the different categories of roots, Dog Ridge put forth the maximum root length in the

Spatial variation in ‘Hayward’ kiwifruit dry matter content within a growing region across seasons

Between-orchard variation in fruit dry matter (DM) content at harvest of 341 commercial ‘Hayward’ kiwifruit orchards was spatially modelled across a production region over consecutive growing seasons (2003–08). Within seasons there were spatial patterns to the distribution of fruit DM between orchards. The temporal consistency of the spatial variation enabled segregation of the production region into two geographic zones which contained orchards that consistently produced fruit of distinct DM both within and across seasons. The differences in fruit DM between geographic zones were statistically significant, but were not of sufficient magnitude to be of commercial interest. Although the location of an orchard within the production region had an effect on the DM of the fruit produced, orchard location was not predictive of fruit DM. Therefore, it is concluded that in this situation zonation between orchards should not be where the effort in managing variation in fruit quality is concentrated.

Variation in dry matter and nitrogen accumulation and remobilization in barley as affected by fertilization, cultivar, and source–sink relations

Barley ( Hordeum vulgare L.) is one of the most important cereals worldwide and is being increasingly grown in many areas of the world, but there is a lack of information about the physiological processes limiting grain yield. A two-year field study was conducted with the objective of determining the effect of different rates of nitrogen (N) (control, 60 kg N ha −1, and 120 kg N ha −1) on source–sink relations, dry matter and N remobilization, and grain yield. Therefore, the source–sink ratio was manipulated to examine the factor(s) limiting grain filling under rainfed conditions. The treatments were: I, control; II, half of the spike was removed; III, the entire spike was removed. The distribution of dry matter, N among grains, and culms and leaves were analyzed at anthesis and harvest. Dry matter accumulation and partitioning into different plant parts were affected by the fertilization treatments and increased as the N level increased. At anthesis, the amount of leaf + culm dry matter was greater than the amount of spike dry matter. N fertilization slightly affected the N concentration of the different plant parts at anthesis and at maturity. N content was affected by the fertilization treatments and was increased by 62% over the two years of the study compared with the control. In addition, dry matter remobilization was an average of 40% higher in the fertilized treatments compared with the control, which indicates that fertilization led plants to translocate higher amounts of dry matter. N remobilization was affected by the fertilization treatment and by the sink reduction. The spike reduction treatment increased the pre-anthesis assimilates and contribution to grain, indicating that the dry matter remobilization from vegetative tissues were very important for grain development. In contrast, N translocation efficiency was similar under sink reduction. Grain yield was determined by biomass and harvest index, and at the half spikes, there was a higher contribution at the harvest index. In addition, grain N yield was determined more by grain yield and less by the N concentration. The present study indicates that N fertilization and sink size can affect dry matter and N accumulation, partitioning, and remobilization in barley, which can affect grain yield.

Effects of Planting Density and Soil Moisture on Flag Leaf Photosynthetic Characteristics and Dry Matter Accumulation and Distribution in Wheat

Water shortage is one of the major problems in wheat (Triticum aestivum L.) production in northern plain in China.Water-saving technique is most important in wheat cultivation.In this study,we adopted water-controlled irrigation based on measuring soil moisture to improve the fixed-amount irrigation strategy in previous studies.Using wheat cultivar Jimai 22,we measured the photosynthetic performance of flag leaf and dry matter accumulation and distribution in plant under two plant densities and three irrigation treatments.In the 2008-2009 growing season,the plant densities were 150 (M1) and 225 (M2) seedlings per square meter,and the irrigation treatments were designed as relative soil moisture (SM) of 65% at jointing and 60% at anthesis (W0),SM of 75% at jointing and 75% at anthesis (W1),and SM of 75% at 7 d after jointing and 75% at 7 d after anthesis (W2).In the 2009-2010 growing season,only one plant density (M1) was adopted,which showed better performance in yield and water use efficiency (WUE) in the 2008-2009 growing season.Besides,the irrigation treatments were adjusted to SM of 75% at jointing and of 60% at anthesis (W'0),SM of 85% at jointing and 75% at anthesis (W'1),and SM of 85% at 7 d after jointing and SM 75% at 7 d after anthesis (W'2).Under the same irrigation treatment,maximal photochemical efficiency of PSⅡ (Fv/Fm) and actual photochemical efficiency of PSⅡ (Φ PSⅡ) under M1 density were higher than those under M2 density from middle to late grain-filling stage,and dry matter accumulation amount after anthesis and dry matter translocation amount to grains in M1 treatment were significantly higher than those in M2 treatment.Compared with W1 treatment,Fv/Fm and ΦPSⅡ of W2 treatment were significantly higher from middle to late grain-filling stage,and photosynthetic rate (Pn),evapotranspiration (Tr),leaf water use efficiency (WUE L),and stomatal conductance (Gs) were also higher in W'2.Under the M1 plant density,the dry matter accumulation amount after anthesis and its contribution to grains were higher in W2 than in W1 treatment,whereas the grain yield and WUE of W2 treatment were significantly higher than those in W1 treatment.The changing tendency of dry matter accumulation and distribution,grain yield,and WUE were similar in both growing seasons.In wheat growing environment similar to the condition of this experiment,we propose the best plant density is 150 seedlings per square meter and the best irrigating both at jointing and anthesis is SM (0-140 cm soil layer) of 75% at 7 d after both stages.

Spatial distribution of dry matter in yellow fleshed cassava roots and its influence on carotenoid retention upon boiling

Understanding retention of carotenoids after different processing methods is important. This study was conducted to quantify dry matter content and carotenoids found in different sections of the cassava roots from six clones and to assess true retention of carotenoids after 30min of boiling. Retention was quantified in normalized prisms taken from proximal, central and distal sectors of the root. Dry matter content (DMC) was measured along and across the roots and varied from 14.1 to 51.0%. DMC tended to be lower at the center of the root and in distal sections. DMC affected the homogeneity of the food matrix and, therefore, contributed in spatial variation in retention of carotenoids. Average true retention (dry matter basis) was 86.6% and ranged from 76.0 and 96.7% (averages per clone and section of the root, respectively). Retention was positively associated with carotenoid content in unprocessed samples, although the relationship was weak. The study shows that during boiling weight of samples changed from slight losses to gains of up to 40% (depending on original DMC of the uncooked root), resulting in an “apparent dilution” of the carotenoids. Results suggested the occurrence of some isomerization. All-trans β-carotene losses (13%) were partially explained by increases in the 13-cis (34%) and 15-cis (8%) isoforms, as well as lixiviation (<1%) into the boiling water.