scholarly journals Water Stress in the Production and Quality of Bidens pilosa and Raphanus raphanistrum Seeds

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
M.R.R. PEREIRA ◽  
C.C. MARTINS ◽  
A.C. SILVA JR. ◽  
D. MARTINS

ABSTRACT: Plants in soils with low water availability may present a reduction of their leaf area and photosynthetic rate, as well as lower assimilated compound supply for seeds. Knowing the physiological quality and seed production of weeds generated under water deficit conditions can help understanding the survival and competition strategies of species. The objective of this work was to evaluate the effect of water stress on the production and germination of Bidens pilosa and Raphanus raphanistrum seeds. Plants were maintained in soils with different water potentials (-0.03, -0.07 and -1.5 MPa) throughout their cycle, until seed production, when they were harvested. Then, evaluations were performed to find out the number of seeds per plant and number of seeds per pod (Raphanus raphanistrum). The evaluation on the germination of these seeds was performed on moistened paper, with four replications, at 20-35 oC and 8 hours of light per day, weekly, until 28 days after seeding. The experimental design was completely randomized with three treatments (soil water potential: -0.03 MPa, -0.07 MPa and -1.5 MPa). The results were submitted to analysis of variance by F test, and the means of the treatments were compared by Tukey’s test at 5% probability. It was concluded that Bidens pilosa is more adapted to water deficit conditions than Raphanus raphanistrum, due to the higher production of seeds, better germination and seedlings with greater vigor.

2012 ◽  
Vol 30 (4) ◽  
pp. 695-698 ◽  
Author(s):  
Cristiaini Kano ◽  
Antonio Ismael Inácio Cardoso ◽  
Roberto L Villas Bôas

Because of lack of information about phosphorus fertilization in lettuce from the standpoint of seed production, this study was undertaken. The work was carried out in Botucatu, São Paulo state, Brazil, from September 25, 2003 to February 19, 2004, in order to study the influence of crescents phosphorus rates on yield and quality of lettuce seeds, cultivar Verônica. The experimental design was randomized blocks with five treatments (0; 200; 400; 600 and 800 kg ha-1 of P2O5) and five replications. The following characteristics were evaluated: seed production per plant (g plant-1), number of seeds per plant and quality (percentage of germination and seed vigor). A linear increasing was observed on production and number of seeds per plant of lettuce with phosphorus rates, but these rates did not affect the seed physiological quality evaluated on weight of 1,000 seeds (average = 0.91 g), first count of germination (98%), standard germination test (99%), seed germination speed index (68.5), seedling emergence speed index (97.0) and emerged seedlings (49.3%).


2021 ◽  
Vol 914 (1) ◽  
pp. 012028
Author(s):  
A D C Putri ◽  
S Indrioko ◽  
A Nugroho ◽  
E Faridah ◽  
Y W N Ratnaningrum

Abstract Based on the genetic base and clonality level, sandalwood (Santalum album) formed two types of landraces along with the Gunung Sewu Global Geopark Network in the southern part of Java islands, Indonesia. These two types are represented by Bejiharjo (which has a low genetic base and high clonality) and Bleberan (which has a high genetic base and low clonality) landraces. This study aimed to observe the quality of sandalwood seeds collected from the two landraces to determine the qualified seeds. We collected and tested all produced seeds of fruiting parent trees from August 2019 to March 2020. The physical and physiological quality tests included counting the number of seeds, measuring the seed size, and testing the viability of seeds. The Bleberan landrace produced 9161 seeds with 22.06% of seed viability. Meanwhile, the Bejiharjo produced only 158 seeds, of which all failed to germinate. Lower genetic base and higher clonality increased the inbred progenies, led to inbreeding depression, and decreased seed production and viability. Therefore, the qualified seed from the Bleberan landraces is worth considering to provide future genetic materials.


2021 ◽  
Vol 10 (2) ◽  
pp. e44710212763
Author(s):  
Pâmela Gomes Nakada-Freitas ◽  
Juliana Tamires dos Santos ◽  
Gabriel Ferraresi Hidalgo ◽  
Louyne Varini Santos dos Anjos ◽  
Emanuele Possas de Souza ◽  
...  

There are researches with calcium to produce the cauliflower inflorescence, but for seeds production no studies were found, this element is fundamental for the fixation of the floral buds and in the production and quality of seeds. The objective was to evaluate the effect of foliar application of calcium on different phenological stages of cauliflower plants in seed production and quality. Eleven treatments were evaluated, varying the number (1 to 4) of calcium (6 g L-1 of calcium chloride) applications and the phenological stages (E1 = floral stem with 30 cm length, E2 = opening of the first flowers; E3 = formation of first siliques; E4 = 50% of silique formed), resulting: T1 = control without application of Ca; T2 = E1; T3 = E1 + E2; T4 = E1 + E2 + E3; T5 = E1 + E2 + E3 + E4; T6 = E2; T7 = E2 + E3; T8 = E2 + E3 + E4; T9 = E3; T10 = E3 + E4; T11 = E4. The results showed a higher seed production per plant in treatments T10 (E3 + E4) and T11 (E4) with 42 and 48 g per plant, and a higher number of seeds per plant, with 12,379 and 12,978, respectively, compared to the control (T1): 23 g and 5,725 seeds per plant. Calcium applications in different phenological stages did not influence the physiological quality (germination and vigor) of cauliflower seeds of cultivar 'Piracicaba Precoce'. Application of these treatments in other cultivars is promising for further studies.


Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1960
Author(s):  
Afonso Henrique Schaeffer ◽  
Otávio Augusto Schaeffer ◽  
Diógenes Cecchin Silveira ◽  
João Arthur Guareschi Bertol ◽  
Debora Kelli Rocha ◽  
...  

Ryegrass (Lolium multiflorum Lam.) is the main winter weed of crops in Southern Brazil. High competitiveness, adaptability, widespread resistance to herbicides and seed dormancy make the plant a permanent problem. Herbicides, as well as plant growth regulators, can be used as a management option for ryegrass seed production, however there is no consensus among authors at which stage of the plant the application is most effective. Thus, this study aimed to evaluate the production and physiological quality of ryegrass seeds in response to the application of herbicides and plant growth regulators in three stages of plant development (inflorescence emergence, flowering and fruit development). Each treatment consisted of applying two different doses of each of the active ingredients: ammonium glufosinate, clethodim, glyphosate, iodosulfuron-methyl, paraquat and 2,4-D (herbicides); ethephon and trinexapac-ethyl (plant growth regulators), still an untreated control, totaling 17 treatments for each stage of development. The experimental design used was randomized blocks, with three replications. The variables evaluated were: seed production (kg ha−1), thousand seed weight (g), viability (%), germination (%), first germination count (%), dormant seeds (%) and dead seeds (%). The ryegrass seed production reduced 100% with clethodim, glyphosate, ammonium glufosinate or paraquat applied in the inflorescence emergence or flowering stages. In the fruit development stage, all treatments (herbicides and plant growth regulators) caused deleterious effects on seed production, the greatest effect occurred with paraquat (95%). Paraquat, ammonium glufosinate and clethodim affected the physiological quality of the seeds when applied in fruit development stage. This research demonstrated that the application of herbicides in the ryegrass reproductive stage decreases its seedbank replenishment (natural re-sowing), with the potential to harm its progeny.


Weed Science ◽  
2013 ◽  
Vol 61 (1) ◽  
pp. 98-103 ◽  
Author(s):  
Bhagirath S. Chauhan

Greenhouse studies were conducted to evaluate the growth response of itchgrass to water stress. Itchgrass plants produced the greatest aboveground biomass and seeds at 75% of field capacity and these parameters at 50 and 100% of field capacity were similar. With further increase in water stress, seed production was sharply reduced, but itchgrass was still able to produce an average of 63 and 9 seeds plant−1at 25 and 12.5% of field capacity, respectively. Itchgrass plants responded to increasing water stress with increased leaf weight ratio; it was 2.5 times greater at 12.5% of field capacity than at 100% of field capacity. In another study, compared with daily irrigation, intervals of 9 d between irrigations reduced aboveground biomass of itchgrass by 27% and 12-d intervals reduced aboveground biomass by 67%. Compared with the daily irrigation regime, itchgrass seed production was reduced by 61% at intervals of 12 d between irrigations; however, the weed plants produced a considerable number of seeds (153 seeds plant−1) at the 12-d intervals. The ability of itchgrass to produce biomass and seeds under water stressed conditions necessitates strategies that minimize weed survival while maximizing irrigation efficiency for the crop at the same time.


Author(s):  
Fernando H. B. Machado ◽  
Andréia M. S. de S. David ◽  
Silvânio R. dos Santos ◽  
Josiane C. Figueiredo ◽  
Cleisson D. da Silva ◽  
...  

ABSTRACT Crop strategies focused on the rational use of water are required in semiarid regions. Thus, the objective of this work was to evaluate the physiological quality of maize seeds produced under soil water deficit conditions. Five irrigation water depth were established, based on the field capacity (100, 85, 70, 55 and 40%), to control the available water for two maize hybrids (2B-587 and DKB-390). A randomized block design was used, with a split-plot arrangement and four repetitions. The plots consisted of irrigation water depths, and the subplots consisted of maize hybrids. The seed water concentration, germination, and vigor were determined after the harvest, using data from first germination counting, seedling emergence, germination speed index, seedling length, and accelerated aging, electrical conductivity, and modified cold tests. The maize hybrid DKB-390 showed better physiological potential under the soil water deficit conditions evaluated. The irrigation water depths lower than 70% of field capacity resulted in decreases in soil water contents and affected negatively the physiological quality of the maize seeds produced.


2021 ◽  
Vol 25 (3) ◽  
pp. 1411-1423 ◽  
Author(s):  
Xiangyu Luan ◽  
Giulia Vico

Abstract. Crop yield is reduced by heat and water stress and even more when these conditions co-occur. Yet, compound effects of air temperature and water availability on crop heat stress are poorly quantified. Existing crop models, by relying at least partially on empirical functions, cannot account for the feedbacks of plant traits and response to heat and water stress on canopy temperature. We developed a fully mechanistic model, coupling crop energy and water balances, to determine canopy temperature as a function of plant traits, stochastic environmental conditions, and irrigation applications. While general, the model was parameterized for wheat. Canopy temperature largely followed air temperature under well-watered conditions. But, when soil water potential was more negative than −0.14 MPa, further reductions in soil water availability led to a rapid rise in canopy temperature – up to 10 ∘C warmer than air at soil water potential of −0.62 MPa. More intermittent precipitation led to higher canopy temperatures and longer periods of potentially damaging crop canopy temperatures. Irrigation applications aimed at keeping crops under well-watered conditions could reduce canopy temperature but in most cases were unable to maintain it below the threshold temperature for potential heat damage; the benefits of irrigation in terms of reduction of canopy temperature decreased as average air temperature increased. Hence, irrigation is only a partial solution to adapt to warmer and drier climates.


Author(s):  
Eduardo Rodríguez-Guzmán ◽  
Luis Javier Arellano-Rodríguez ◽  
Alicia De Luna-Vega ◽  
Cruz Arriaga-Ruiz

Fruit and seed productive capacity and physiological seed quality of 2 varieties of husk tomato were estimated: Jojutla and CHF1. The study was conducted in hydroponics under greenhouse, in the CUCBA-UDG, Zapopan, Jalisco. Red volcanic rock (/Tezontle) of 0.5 to 2 cm in diameter was used in 19 L polyethylene bags and Steiner's universal nutrient solution of 0.3 to 0.7 atm, depending on the stage of the plant. The production of fruit and seed and the physiological quality of the seed were estimated. The varieties Jojutla and CHF1 showed a similar behavior in the production of fruit and seed, with lower fruit yields than expected (30 ton / ha in the field) because only 3 harvests were made, looking to produce husk tomato in winter when it reaches attractive prices. The weight of the fruit was greater as cuts were made while the seed production improved by cutting, associated with a greater number of fruits, while the weight of the fruit was not related to the seed yield. The physiological quality of the seed was affected by cutting the fruit to commercial maturity even when it was left to mature in the shade.


2008 ◽  
Vol 48 (9) ◽  
pp. 1232
Author(s):  
J. M. Lee ◽  
K. Elborough ◽  
D. Whittaker ◽  
D. J. Donaghy ◽  
J. R. Roche

Insufficient water availability is one of the most serious environmental stresses for a plant and can be a major limitation to herbage production in many regions. Plant hormones, such as cytokinins, have been reported to reduce the detrimental effects of low water availability in many different plant species. However, there is little research available concerning the effect on pasture grasses. The aim of the present study was to quantify the effect of surface applications of 6-benzylaminopurine (BAP) before and during water deficit on herbage growth and quality of perennial ryegrass–white clover pastures. Pastures fertilised with BAP were compared with unfertilised pastures and pastures receiving nitrogen. Exogenous BAP application did not significantly affect herbage production or quality relative to unfertilised pastures. Nitrogen fertiliser increased total herbage production, but had little effect on herbage quality compared with BAP. The failure of surface applications of exogenous BAP to improve herbage production or quality suggests that it is not an appropriate method to enhance plant tolerance to water deficit at the concentration applied in this study.


2019 ◽  
Vol 7 (2) ◽  
pp. 297
Author(s):  
Francisco Jose Basilio Alves ◽  
Antonio Lucineudo Oliveira Freire

This research aimed to evaluate the physiological responses of Mimosa tenuiflora plants submitted to variable water availability conditions during the nursery stage. Twelve-month-old plants kept in plastic pots containing 5 kg of the substrate composed of the subsoil soil mixture and bovine manure (2:1) were submitted to two treatments: irrigated (control) and water stress, which was imposed through the suspension of irrigation, rewatering after seven days of stress. The relative water content (RWC) and stomatal parameters were evaluated. The M. tenuiflora plants responded quickly to the irrigation suspension, promoting the closure of the stomata, occurring reduction in stomatal conductance, transpiration rate and photosynthesis. The instantaneous efficiency in water use of plants under water deficit remained high only until the middle of the period when irrigation was suspended, and then declined until the last day of the water deficit. After rehydration, the plants showed recovery in all evaluated parameters, indicating that the level of stress imposed did not cause irreversible damages in the cells and tissues.


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