Dry Mass Partitioning Research Articles

Far-red radiation increases dry mass partitioning to fruits but reduces Botrytis cinerea resistance in tomato

The addition of far-red (FR, 700–800 nm) radiation to standard growth light triggers a set of photomorphogenic responses collectively termed shade avoidance syndrome. Recent research showed that additional FR increased fruit yield in greenhouse tomato production. However, the mechanism behind this increase is not clear; nor is it known whether there is a trade-off between growth and defense against plant diseases in tomato under additional FR. The aims of this study were 1) to quantify the effect of additional FR on tomato fruit growth, 2) to explain this effect based on underlying growth components and 3) to examine the FR effect on resistance against the necrotrophic fungus Botrytis cinerea. Tomato (Solanum lycopersicum ‘Moneymaker’) plants were grown for four months with 30 or 50 μmol m−2 s−1 of FR added to 150 μmol m−2 s−1 red + blue or white background LED lighting. Growth and development parameters were recorded, and a growth component analysis was conducted. Bioassays for resistance against B. cinerea were conducted on leaf samples collected from each light treatment. Additional FR increased total fruit dry mass per plant by 26–45%. FR affected multiple growth components, among which the fraction of dry mass partitioned to fruits was the most prominent with a 15–35% increase. Truss appearance rate was increased 11–14% by FR while instantaneous net photosynthesis rate was not affected. FR also resulted in more severe disease symptoms upon infection with B. cinerea. In conclusion, additional FR increases tomato fruit production mainly by increasing dry mass partitioning to fruits, rather than improving photosynthesis or increasing total plant biomass. However, FR also reduces resistance of tomato leaves against B. cinerea.

Growth and quality of lisianthus [Eustoma grandiflorum (Shinn.)] cultivated in rice husk substrates in troughs with leaching recirculation

This study aimed to evaluate the growth and quality of lisianthus cultivated in different rice husk substrates. The evaluated substrates were: carbonized rice husk (CRH; 100%); raw rice husk (RRH; 100%); CRH (70%) + S10 Beifort® commercial organic compost (30%); and RRH (70%) + S10 Beifort® commercial organic compost (30%). Plant dry mass (DM) production and partitioning, plant leaf area and shoot/root DM ratio were analyzed. Quality parameters of the flower stems were also evaluated (length; diameter and number of flowers and buds). The RRH substrate at 100% reduced plant growth and prevented flower development. This modified dry mass partitioning among the plant organs. The substrates RRH + S10 and CRH provided quality flower stems. Thus, both substrates can be used to produce cut lisianthus flowers in recirculating nutrient systems. However, the RRH + S10 substrate stood out because it increased plant growth. This result is ascribed to the improvement of the physical and chemical properties of substrate RRH + S10 as a result of the presence of both the organic compost, which benefited the water holding capacity, and the RRH, which guaranteed high porosity to the substrate.

Performance of Chia on Different Sowing Dates: Characteristics of Growth Rate, Leaf Area Index, Shoot Dry Matter Partitioning and Grain Yield

The objective of this study was to comparatively determine the characteristics of growth rate, leaf area index, shoot dry mass partitioning and grain yield of chia plants (Salvia hispanica L.) on different sowing dates. A field experiment was conducted in the crop year of 2016/2017 in five sowing dates (09/22/16, 10/28/16, 01/03/17, 02/08/17 and 03/24/17) with a randomized complete block design and four replicates. Plant growth was determined through field samplings to determine the dry matter mass and leaf area performed every 15 days. The following physiological indexes were calculated: relative growth rate, absolute growth rate, net assimilation rate, leaf area ratio, specific leaf area and leaf mass ratio. To weekly evaluate plant height, ten plants per plot were marked after emergence, and the final height was considered when plants reached physiological maturity. A useful area of 2.10 m² per plot was collected for evaluating grain yield. The physiological indexes indicated that at earlier sowing dates there is a greater plant growth, either in shoot dry matter mass, height and leaf area index. The leaf area index of branches is progressively increased with plant development and contributes significantly to total leaf area index of chia plants in all studied sowing dates. The main stem represents between 60 and 70% of the shoot dry matter accumulated in the early sowing dates, and between 40 and 50% in late sowing. The best sowing date in terms of grain yield is 01/03/17.

Artificial shading promotes growth of taro plants

ABSTRACT Taro (Colocasia esculenta) is a plant with a long crop cycle, what hinders its cultivation in properties with area limitations. The association of crops is an option for this kind of situation. However, in order to plan the cultivation using the intercropping system, it is important to define the tolerance levels of the taro plants and the period of highest sensibility to shading. This study aimed to evaluate the behavior of the 'Japanese' taro crop, regarding growth, cultivated under levels and periods of artificial shading. A split-plot randomized block design, with 13 treatments and four replications, was used. The plots consisted of four shading levels (control = full sun, 18 %, 30 % and 50 % of shade), maintained throughout the cycle or during three months, in three periods (initial = 0-3 months; intermediate = 3-6 months; final = 6-9 months). The subplot was composed of eight plant samples (60, 90, 120, 150, 180, 210, 240 and 270 days after planting). The shading levels increased the total and specific leaf area, leaf area and mass ratios and dry mass partition. Thus, the taro plants showed the capacity to make leaf adjustments to suit changes in light intensity. The shading intensity of 18 %, during the whole cycle or in any of the periods studied, provides a high expansion of the leaf area.

Fast-growing Larix kaempferi suffers under nutrient imbalance caused by phosphorus fertilization in larch plantation soil

Abstract There are significant differences in the morphological and physiological responses of larch species with contrasting growth rates under fertilization. However, little is known about species-specific differences in responses to nutrient imbalance caused by fertilization. Therefore, in this study, the effects of nitrogen (N) and phosphorus (P) fertilization on the morphological, physiological and chloroplast ultrastructural traits of two contrasting larch species, fast-growing Larix kaempferi and slowly-growing L. olgensis, grown in larch plantation soil, were investigated during two growth seasons. It was shown that N and combined N and P (NP) fertilization increased plant photosynthesis, foliar N contents, chlorophyll contents, and dry mass accumulation and partitioning in aboveground organs in both larch species. Although P fertilization enhanced P accumulation, its presence reduced the N content in soluble proteins in the foliage of both larch species. Yet, P fertilization exhibited some differences in the two species: P fertilization increased photosynthesis, chlorophyll content and biomass accumulation of L. olgensis, while it decreased these parameters dramatically in L. kaempferi. P fertilization increased foliar N content in L. olgensis, while it reduced it in L. kaempferi. P fertilized L. kaempferi had more damaged chloroplast ultrastructure than L. olgensis. In addition, L. kaempferi exhibited lower acid phosphatase activities, and higher photosynthesis and biomass accumulation than L. olgensis, except under P fertilization. L. kaempferi allocated more biomass into needles, except under P fertilization, while L. olgensis allocated more into stems under fertilization. In conclusion, it was shown that nutrient imbalance caused by P fertilization has greater negative effects on a fast-growing species than on a slowly-growing one, and the negative effects are related to differences in acclimation strategies, N partitioning to photosynthetic components, and P transportation and metabolism in the foliage.

Responses of radish (Raphanus sativus) to drought stress

AbstractWith this study the effects of water deficit on radish growth, dry mass production and partitioning, source–sink relations, physiological responses and accumulation of secondary metabolites in storage roots and leaves have been investigated. Three water stress treatments were applied: (Control) 100% of water holding capacity (WHC), (WS50) 50% of WHC, (WS30) 30% of WHC. Water stress was effectively acquired starting from 287 growing degree days (GDD) as demonstrated by the lower values of relative water content (RWC), higher leaf temperature and NIR‐based water indices values in water stressed conditions. Water stress reduced storage root dry weight by 27% at WS50 and 53% at WS30 as well as leaf dry matter accumulation (by 23% and 31% in WS50 and WS30, respectively), expansion (by 28% and 45% in WS50 and WS30, respectively) and specific leaf area (by 7% and 20% in WS50 and WS30, respectively) at 403 GDD. The increasing of leaf‐to‐root mass (L/R) and leaf area‐to‐root mass (LA/R) ratios indicated less dry matter allocation into storage organs under water stress conditions. Besides, water shortage increased leaf greenness as estimated by the higher soil–plant analysis development (SPAD) values (+14% and +20% on average for WS50 and WS30, respectively); other reflectance indices only partially confirmed SPAD readings. Substantially, water limitation did not significantly influence total anthocyanin content, ABTS‐radical scavenging activity and total free phenolic compounds in storage roots, as well as the total free phenolic compounds in leaves. Radish showed a strong plasticity in its adaptation to drought thanks to avoidance mechanisms such as constrained leaf development, increased leaf thickness and adjusted source–sink relationships.

Response of grapevine (Cabernet Sauvignon cv) to above ground and subsurface drip irrigation under arid conditions

The response of wine grapes to irrigation systems was investigated in a Cabernet Sauvignon/140 Ru vineyard in sandy loam soil in Sicily during a two-year study. Two different drip irrigation systems were evaluated: one surface drip and two subsurface drip irrigation systems, with the trickle line located at different distances from vine trunks. Vegetative and quantitative parameters, must quality and root distribution were compared among irrigation treatments. During the two study years, irrigation of grapevines via a subsurface drip system resulted in greater water use efficiency without affecting must composition. Establishing the trickle line near the trunk positively influenced trunk growth and total root contact while establishing the trickle line 1.20m from the trunk increased yield. Dry mass partitioning was modified in subsurface irrigation treatments in favour of reproductive organs. We conclude that subsurface drip irrigation under the trunk can be successfully used under water deficit irrigation management, even in sandy loam soil and in the hot climate conditions of the Mediterranean vineyard. Some aspects of management deserve further investigation and further studies may better define the optimum conditions for the successful utilization of the SDI 120 irrigation strategy.

Ecophysiological responses of dual-purpose wheat originating from different cutting management systems

Wheat is one of the most cultivated cereals worldwide. Some wheat genotypes may be used for dual purposes that is, in the production of animal fodder and grains. The objective of this study was to compare the growth, partitioning of assimilates, and seed vigor expression of dual-purpose wheat cultivars originating from seeds produced by plants subjected to different cutting management systems. Dual-purpose wheat seeds in the vegetative period were used for this study; these were obtained from the cultivar BRS Umbu produced by plants subjected to different cutting management systems. The experimental design was completely randomized in a factorial scheme, with four replications. The treatments comprised a combination of four seed production systems (one, two, and three cuts) and eight planting seasons (10, 20, 30, 40, 50, 60, 70, and 80 days after emergence [DAE]). Total dry-mass, dry-mass production rate, relative growth rate, net assimilation rate, leaf area index, solar energy conversion efficiency, dry-mass partitioning, seedling emergence in the field, and emergence speed index were evaluated. Data regarding seedling emergence and emergence speed index were adjusted by orthogonal polynomials. Primary growth data were evaluated from the simple logistic equation. From 60 DAE, an inversion of the values of total dry-mass was observed, and the maximum values were observed in plants from seeds produced without cutting management. The highest dry-mass production rates were noted for plants produced by seeds of plants not subjected to cutting management. The highest relative growth rates were noted among plants originating from seeds produced by plants subjected to three- and two-cut treatments. The net assimilation rate was higher in plants originating from seeds produced from plants subjected to cutting management systems. The highest values of emergence were observed for seeds obtained from the three-cut treatment. Similarly, an increase in the values of emergence speed index was observed in seeds from plants subjected to one-cut treatment. Dual-purpose wheat cultivars originating from seeds produced in the absence of cutting management presented higher total dry-mass, dry-mass production rate, and relative growth rate. The net assimilation rate was higher in plants from seeds produced with cutting management systems. Plants produced from seeds subjected to the three-cut production management resulted in more vigorous seeds.

Primed Acclimation of Papaya Increases Short-term Water Use But Does Not Confer Long-term Drought Tolerance

Primed acclimation (PA) is a regulated deficit irrigation (RDI) strategy designed to improve or maintain yield under subsequent drought stress. A previous study showed photosynthetic increases in papaya in response to a PA treatment. The present study was undertaken to test the duration of the PA effect when papaya plants were challenged with severe drought stress. Potted plants were stressed at 1, 2, and 3 months after conclusion of a PA treatment consisting of 3 weeks at soil water tension (SWT) of −20 kPa. Measurements included leaf gas exchange, root growth, and organ dry mass partitioning. PA did not reduce net CO2 assimilation (A) during the deficit period. At the end of the PA period, total dry matter accumulation per plant and for each organ was unaffected, but proportional dry matter partitioning to roots was favored. After resuming full irrigation, A increased and whole plant water use was more than doubled in PA-treated plants. However, water use and A of PA-treated plants decreased to reconverge with those of control plants by 6 weeks after the PA treatment. Over the course of the study, PA plants maintained lower stem height to stem diameter ratios, and shorter internode lengths. However, these changes did not improve photosynthetic response to any of the water-deficit treatments. We conclude that papaya exhibits some signs of stress memory, but that rapid short-term acclimation responses dominate papaya responses to soil water deficit.

The effects of oil palm’s empty fruit bunch compost with hexaconazole on biomass production and nutrient contents of sweet potato var. VitAto cultivated on sandy soil

This experiment was conducted to investigate the effects of various treatment combinations consisting of oil palm’s empty fruit bunch (EFB) compost and hexaconazole (HEX) on dry mass production, partitioning and nutrient concentrations and contents of sweet potato var. VitAto. The treatments consisted of the recommended inorganic fertilizer for VitAto cultivation (control), solely EFB compost and the combination of treatments consisting of EFB compost with 10 or 30 ppm HEX, using a randomized complete block design (RCBD) replicated four times on sandy soil. The destructive biomass analysis was carried out at 30, 55, 77 and 99 days after planting, which corresponded to the following growth stages, storage root initiation, early and middle bulking and maturity, respectively. The final biomass harvest (99 days after planting) was used for N, P and K nutrient analysis. The greatest response was observed using EFB compost plus 30 ppm HEX treatment, which significantly increased storage root dry mass production, storage root mass ratio, root to shoot ratio, plant total K content, storage root K concentration and content by 16.9%, 15.2%, 58.8%, 75.5%, 69.4% and 106.9% at the maturity stage, respectively. The results showed that the control treatment favored the growth of leaf and stem, while the EFB compost with 30 ppm HEX treatment favored the growth of storage root. The EFB treatment was able to supply high K nutrient to the plant. Both K and HEX were able to increase the assimilate translocation to storage root and consequently increased the storage root dry mass production. Based on the finding of this study, it is proposed that the EFB compost with 30 ppm HEX combination treatment could be used by farmers as alternative inputs to the inorganic fertilizer application in VitAto cultivation on sandy soil.

Photosynthesis and biomass allocation of cotton as affected by deep-layer water and fertilizer application depth

Available water stored in deep soil layers could increase the photosynthetic capacity of cotton. It was hypothesized that the photosynthesis of cotton would be enhanced by changing the fertilizer application depth under different deep-layer water conditions. We examined two deep-layer water levels, i.e., well-watered (W80) and not watered (W0), combined with surface application (F10) and deep application (F30) of basal fertilizer. Compared to W0, W80 resulted in increased leaf area (LA), photosynthetic pigment contents, maximal PSII efficiency (Fv/Fm), effective quantum yield of PSII (YII) and PSI (YI), electron transport rate of PSII (ETRII) and PSI (ETRI). W80 also increased the aboveground and root dry mass by 39 and 0.6%, respectively, and decreased the root/shoot ratio by 40–73%. Under the W0 condition, higher values of Fv/Fm, YII, YI, ETRII, and ETRI were measured for F10 compared to F30 after 69 d from emergence. Under the W80 condition, cotton plants with F10 showed higher LA, Fv/Fm, YII, YI, ETRII, and ETRI, but there were no significant differences in the photosynthetic pigments compared to F30. Our results suggest that sufficient water in deeper soil layers and the surface application of basal fertilizer could increase photosynthetic activity and efficiency, which promoted aboveground dry mass accumulation and partitioning towards reproductive organs.

Salinity Effect on Dry Mass Partitioning in Different Plant Parts and Ion Uptake in Leaves of Rice Mutants

The Four levels of sodium chloride induced salinity levels, 0, 6, 9 and 12 dSm-1 were imposed at 25 days after planting of six rice mutants. Results indicated that morphological parameters such as plant height and leaf area, dry mass production in different plant parts such as root, stem, leaf and grain yield hill-1, physiological characters such as biological yield and harvest index, yield attributes such as number of effective tillers hill-1, number of grains panicle-1 and 1000-grain weight, mineral ions in leaves such as potassium and calcium were decreased with gradual increasing of salinity levels while number of non-effective tillers hill-1 and Na content of leaves were increased with increasing soil salinity. The highest value of the above parameters was observed in control and the lowest values of them were observed at 12 dSm-1. Generally genotypes having ability to exclude Na from leaves were found salt tolerant in respect of dry mass production in different plant parts and vice versa. Among the genotypes, the dry matter production and yield loss due to salinity was less in RM250-170 and RM250-2080 than that in the others, which further revealed that RM250-170 and RM250-2080 had a greater tolerance to salinity than RM350-130, RM300- 280, RM250-1080 and IRATOM. The rank of salinity tolerance was: RM250-2080 > RM250-170 > RM250-1080 > IRATOM > RM300-280 > RM350-130.DOI: http://dx.doi.org/10.3329/jesnr.v6i1.22073 J. Environ. Sci. & Natural Resources, 6(1): 239-245 2013

Growth and dry mass partitioning in plant parts of lentil

The experiment was carried out under sub-tropical condition (24°75´ N latitude and 90°50´ E longitude) to investigate the growth, dry mass production and its partitioning into plant parts of three lentil varieties viz. BINA masur1, BINA masur2 and BINA masur3. The leaf area and total dry mass plant−1 were superior in BINA masur3 over its growth period followed by BINA masur2 with same statistical rank. In contrast, BINA masur1 performed inferiority in leaf area and total dry mass plant−1. Dry mass partitioning into seed (HI) was significantly greater in BINA masur2 and BINA masur3 with being the highest in BINA masur2 but total economic yield and its related traits were greater in BINA masur3 than in BINA masur2. Results indicated that percent contribution of dry mass partitioning into different plant parts had no significant influence on seed yield but leaf and stem dry mass production had influence on seed yield in lentil. BINA masur3 produced the highest in leaf and stem dry mass and also showed the highest seed yield followed by BINA masur2. In contrast, BINA masur1 showed the lowest seed yield for contributed lower leaf dry mass.

Water stress effects on growth, yield and quality traits of red beet

The response of red beet to drought stress was investigated in order to explore the adaptive changes in plant growth, dry mass production and partitioning, yield, and accumulation of nutrients and bioactive molecules. Glasshouse experiments were conducted in 2012. Three water stress treatments were applied: (W100) 100% of water holding capacity (WHC), (W50) 50% of WHC, (W30) 30% of WHC. Water stress reduced storage root weight by 62% at W50 and 75% at W30 as well as leaf water content (LWC). With the progressive water stress, plant allocated less dry matter into roots leading to reductions of 32% and 43% in W50 and W30, respectively as compared to W100. Stomatal conductance was strongly reduced (from 496 to 211mmolm−2s−1 in W100 and W30, respectively); canopy temperature (CT) reflected the available water, with differences of 11°C. Drought induced a significantly higher concentration of total phenolic content (a 86% increase) and betalains (52% and 70% increases in betacyanin and betaxanthin) and consequently, a higher antioxidant activity was obtained. Minerals such as Mg, P and especially Zn (2.9 and 1.1mg 100g−1 DW in W50 and W100, respectively) and Fe (5.6 and 2.4mg 100g−1 DW in W30 and W100, respectively) were highly concentrated in water stressed roots alike NDF and ADF. In contrast, °Brix, pH and total not-structural sugars were reduced by water stress, although the sucrose fractions of fructose and glucose concentrated more in W30 plant roots than W100 (18% and 33% higher, respectively). Red beet showed a strong plasticity in its adaptation to drought thanks to avoidance mechanisms (constrained leaf and storage root development) and tolerance mechanisms (increased FLV and thermal dissipation). Interestingly, the high concentration in phytochemicals and nutrients may contribute to the maintenance of human health and may reduce the risk of chronic diseases.

고압나트륨등 조사가 파프리카의 동적 생장과 건물분배율에 미치는 영향

본 연구의 목적은 고압나트륨등 광원(HPS)을 조사하여 파프리카의 동적생장과 기관별 건물분배율 및 광이용효율에 미치는 효과를 구명하고자 수행하였다. 파프리카 육묘는 2010년 9월 29일에 <TEX>$m^2$</TEX>당 3.75주를 정식하여 2010년 12월 14일부터 HPS 광원을 실험종료일까지 하루 16시간 조사하였다. HPS 처리는 엽수를 증가시켰으나, 절간수와 엽면적에는 미비한 영향을 미쳤다. HPS 처리구의 초장은 대조구에 비해 짧았으나, 줄기당 착과수의 증가를 나타냈다. 줄기와 과실 및 총건물중은 HPS 처리구가 대조구보다 각각 28.5%, 97.1%, 67.8%를 증가시켰다. 총 건물중의 증가율 대비 엽과 줄기 생장율을 비율로 나타낸 각 기관의 건물분배율은 생육초기에 45-47%로 동일하다가 과실의 생장이 시작되는 시점에서 급격히 감소하였다. 영양생장기관으로의 건물분배율은 대조구에서 HPS 처리구보다 4% 높았다. 과실로의 평균 건물 분배율을 HPS 처리구에서 대조구에 비해 14.2% 증가하였다. 동적생장량은 지수선형함수의 최대상대생장율, 최대 절대생장율 및 손실일수로 잘 묘사할 수 있었다. 대조구에 비해 처리구의 엽의 최대절대생장율은 18.6%, 줄기는 74.7%, 과실은 143.5%가 증가하는 것으로 추정되었다. 총 건물중에 대한 광이용효율(LUE)은 HPS 처리구에서 <TEX>$4.90g{\cdot}MJ^{-1}$</TEX>로 대조구의 <TEX>$3.84g{\cdot}MJ^{-1}$</TEX> 높았으며, 영양생장기관의 LUE는 HPS 처리구가 <TEX>$1.56g{\cdot}MJ^{-1}$</TEX>로 대조구의 <TEX>$1.61g{\cdot}MJ^{-1}$</TEX>보다 약간 낮았으며, 과실 생산에 대한 LUE는 처리구가 <TEX>$3.34g{\cdot}MJ^{-1}$</TEX>로 대조구 <TEX>$2.23g{\cdot}MJ^{-1}$</TEX>보다 49.8% 증가하였다. 처리간 총 건물중의 LUE의 차이는 HPS 처리구의 과실생산에 대한 LUE가 높았기 때문에 발생되었다. The objective of this study was to describe and analyze the effect of high pressure sodium lamp lighting (HPS) on dynamics of growth and dry matter partitioning, and light use efficiency of sweet pepper crop grown over winter season. Young sweet pepper seedlings were planted at 3.75 plants per <TEX>$m^2$</TEX> on September 29, 2010 and treated with HPS for 16 hours from December 14, 2010 until March 18, 2011. The number of leaves per plant were significantly increased with HPS, whereas the number of internodes and leaf area were less affected. HPS reduced the plant height with higher number of fruits per stem compared to those of without HPS lighting (CON). There were large differences in total dry mass production, stem and fruit dry mass between HPS and CON and those with HPS increased by 67.8%, 28.5%, and 97.1% compared to CON, respectively. Each organs of dry mass partitioning was calculated by leaf, stem or fruit growth rate divided by total plant growth rate. Dynamics of dry mass partitioning to leaf and stem between HPC and CON was measured in range of 45-47% at beginning of growth phase and drastically decreased after starting fruit growth in both treatments. Dry matter partitioning to vegetative organs was 4% higher compared to the plant grown under HPS lighting. Averaged dry matter partitioning to fruit with HPS, however, was largely increased by 14.2% compared to CON. Dynamics of the plant growth were well described by expolinear growth equation with three parameters of maximum relative growth rate, absolute growth rate and lost time to reach linear phase. The maximum growth rate of leaf, stem and fruit with HPS was increased by 18.6%, 74.7%, and 143.5% compared to CON. There was a linear relationship between intercepted light integral and vegetative organs (leaf and stem), fruit or total dry mass production. Light use efficiency (LUE, <TEX>$g{\cdot}MJ^{-1}$</TEX>) of total dry mass was <TEX>$4.90g{\cdot}MJ^{-1}$</TEX> for HPS and <TEX>$3.84g{\cdot}MJ^{-1}$</TEX> for CON, LUE of vegetative organs was <TEX>$1.56g{\cdot}MJ^{-1}$</TEX> for HPS and <TEX>$1.61g{\cdot}MJ^{-1}$</TEX> for CON and LUE of fruit dry mass was <TEX>$3.34g{\cdot}MJ^{-1}$</TEX> for HPS and <TEX>$2.23g{\cdot}MJ^{-1}$</TEX> for CON. The difference in LUE of total dry mass between treatments, therefore, occurred mainly from the different in LUE of fruit dry mass.

갯메꽃의 수분스트레스에 대한 물질분배 특성

Dry matter allocation characteristics of Calystegia soldanella, grown in pots, was analysed to assess its plasticity in response to water-stressed conditions. As water was withheld leaf water potential between the two watering treatments was similar during the first 6 days, followed by a rapid decrease in water-stressed plants. The minimum leaf water potential was -1.50 MPa on day 15 and the maximum leaf water potential was about -0.5 MPa on day 0 in water-stressed plants. In well-watered plants leaf water potential was maintained almost consistently throughout the experiment. There was no significant difference in plant dry weight between the two watering treatments for 9 days after the start of experiment and that was remarkably increased thereafter, compared with that remained without any increase in water-stressed plants. In dry mass partitioning, however, the water-stressed plants showed a great plasticity, showing that there were 1.81, 1.35 and 0.81 times increase in root, stem and leaf, respectively. Dry mass partitioning in well-watered plants varied from 2% to 5%. The difference of dry mass partitioning between the two watering treatments was reflected in leaf mass per unit area (LMA) and root/shoot (R/S) ratio. LMA in water-stressed plants was lower than that in well-watered plants, while R/S ratio in water-stressed plants was higher in well-watered plants. This means that the water-stressed plants reduced its leaf area and increased dry mass partitioning into root and stem during the progress of soil drying. These results indicate that Calystegia soldanella inhabiting in sand dune cope with water stress with high plasticity which can adjust its dry mass partitioning according to soil water conditions.

A species-specific critical nitrogen dilution curve for sunflower (Helianthus annuus L.)

For annual and perennial crops, mathematical models have been developed to describe tissue nitrogen (N) dilution during crop growth and to estimate the plant N status applying the N nutrition index (NNI), the ratio between the actual tissue N concentration ([N]) and the tissue N concentration needed to obtain the maximum instantaneous crop growth rate (critical tissue N concentration, [N]c). The relationship between shoot [N]c and shoot dry matter (DM, tha−1) can be described by an allometric power equation: [N]c=aDM−b, where a and b are crop-specific parameters. Critical N dilution curves (CNDC) have been determined for several C3 crops but not specifically for sunflower (Helianthus annuus L.). The objectives of this work were to (i) determine and validate the N dilution curves for critical, minimum, and maximum [N] for sunflower from the juvenile stages to the end of flowering, (ii) compare the critical curve with published CNDCs for other C3 crops, and (iii) estimate the range of variation of NNI for different levels of N fertilization and irrigation. A wide range of field experiments from Argentina, Australia, France, Italy, and Spain was used to establish the dilution curve for sunflower and to independently validate it. The fitted CNDC [N]c=4.53DM−0.42 yielded lower values for [N]c than references used until now for diagnosis and decision making in sunflower. The value of parameter a was generally similar to that of other C3 species, but the value for parameter b differed. This was possibly associated with species differences in dry mass partitioning, and justified the development of a sunflower-specific CNDC. A preliminary reference curve for maximum [N] suggested an evolution from the juvenile stages to the end of flowering similar to that of [N]c. Minimum [N], in contrast, appeared to be more constant over time. Relationships between relative grain yield and NNI across a range of locations indicated that in general, maximum grain yield was reached around NNI=0.8, although at one location this was around NNI=1.0. The CNDC can provide useful applications for crop modeling, N status diagnosis, and N fertilization decision.

Influence of NaCl Salinity and Different Substracts on Plant Growth, Mineral Nutrient Assimilation and Fruit Yield of Strawberry

A hydroponic culture was carried out with strawberry cv. Camarosa to investigate the effects of four salinity levels and four different substrates on plant growth, mineral nutrient assimilation and fruit yield of strawberry. Total dry weight accumulation of plants was not inhibited at low salinities, but it was significantly inhibited at 60 mM NaCl. Dry mass (DM) partitioning in NaCl-stressed plants was in favor of crown and petioles and at the expense of root, stem and leaf, whereas leaf, stem and root DM progressively declined with an increase in salinity. Specific leaf area (SLA) and leaf area ratio (LAR) significantly decreased in cv. Camarosa at 60 and 90 mM. Results also showed that the presence of NaCl in the root medium induced an increase in total Na+ content of the plants in the shoot and root. Despite Na+ and K+, the increase in total inorganic ions resulted from increasing salinity, with Ca2+ and Mg2+ concentrations decreasing in shoot and increasing in roots with an increase in salinity. For all micro- and macroelements however, significant concentration changes related to different substrates were not detected in the present experiments. Results also showed a significant decline of Fe content of 40% and 49% in shoot and root, respectively.

Effect of pruning history on growth and dry mass partitioning of jatropha on a plantation site in Madagascar

While technical aspects of oil processing of seeds of jatropha are under intensive investigation, comparably little is known about the performance of jatropha in the field. We investigated the effects of water availability (rainfed versus irrigated) and pruning-induced differences in plant stature on growth, biomass partitioning, and canopy size at a plantation site in Madagascar in 2010. Plants of different pruning types differed in trunk height (43 versus 29 cm) and primary branches total length (171 versus 310 cm). The two pruning types had effects on dry mass formation and leaf area projection (LAP) during the vegetation period. Trees which had a shorter trunk and longer lateral branches produced more biomass and had a higher LAP. Total dry mass formation varied from 489 to 912 g m � 2 and LAP from 3.26 to 7.37. Total aboveground biomass increased from 2.3 � 0.5 to 4.89 � 1.4 kg tree � 1 and from 4.6 � 1.8 to 8.9 � 1.0 kg tree � 1 for the pruning types with shorter and longer lateral branches, respectively. Growth of twigs and leaves was positively correlated with total length of branches. Relative dry mass allocation to branches, twigs and leaves, length of twigs per cm of branches and specific leaf area (13.57 � 0.72 m 2 kg � 1 ) were not affected by pruning and water supply. Trees with shorter branches had higher LAD. Results indicate that pruning type should be considered as a management tool to optimize biomass production. Detailed studies on effects of canopy size and shape on radiation interception and growth are required to improve the productivity of jatropha. a 2011 Published by Elsevier Ltd.

Influence of water deficit and genotype on photosynthetic activity, dry mass partitioning and grain yield changes of winter wheat

Pn-PAR response curves, gas exchange, dry mass partitioning and grain yield of four different genotypes of wheat were investigated in a randomized complete block design under different watering regimes (85, 55 and 25% FC). The results indicated that genotype differences existed in the adaptation response to water deficit which included change to growth strategies coupled with photo-physiological strategies. Water treatment was the dominating factor which limited plant growth, productivity and yield. As water deficit increased, stomatal conductance (gs), saturation irradiance (SI) and maximum net photosynthetic rate (Pmax) decreased, while irrigation water use efficiency (IWUE), compensation irradiance (CI) and dark respiration (R(D)) increased in all genotypes, with a more rapid decline in wet climate cultivars. Differences in photosynthetic responses existed in different climate genotypes at 55% FC. Reduction of Pn for the wet climate cultivar was mainly due to gs, while for the dry climate cultivar, Pn coupled with photosynthetic pigment increased. At 25% FC, water deficit decreased Pn attributed to non-stomatal limitations in four genotypes. Dry mass was reduced in droughted plants and the percentage increased in dry mass allocated to roots. Furthermore, the wet climate genotypes had the greatest decrease in Chla/b ratio. These findings demonstrated that the superior drought resistance in dry climate cultivars could be attributed to higher photosynthetic capacity, dry matter allocation and then grain yield.