Growth Responses of Pepper Plant (Capsicum annuum L.) in Terms of Biomass Production and Water Uptake under Deficit Irrigation System, Mild Water Stress Conditions

Author(s):  
Sara Mardani ◽  
Mohammad Pessarakli ◽  
Rachel McDaniel
2017 ◽  
Vol 40 (11) ◽  
pp. 1569-1579 ◽  
Author(s):  
Sara Mardaninejad ◽  
Hamid Zareabyaneh ◽  
Sayyed Hassan Tabatabaei ◽  
Mohammad Pessarakli ◽  
Abdolrahman Mohamadkhani

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1419
Author(s):  
Saray Gutiérrez-Gordillo ◽  
Javier de la Gala González-Santiago ◽  
Emiliano Trigo-Córdoba ◽  
Alfredo Emilio Rubio-Casal ◽  
Iván Francisco García-Tejero ◽  
...  

In recent years, the area dedicated to modern irrigated almond plantations has increased significantly in Spain. However, the legal irrigation allocations are lower than the maximum water requirements of the crop in most cases. Therefore, almond growers are forced to implement regulated deficit irrigation strategies on their farms, applying water stress in certain resistant phenological periods and avoiding it in sensitive periods. Given the need to monitor the water status of the crop, especially in the most sensitive periods to water stress, the objective of this work was to evaluate the sensitivity of two UAV-based crop water status indicators to detect early water stress conditions in four almond cultivars. The field trial was conducted during 2020 in an experimental almond orchard, where two irrigation strategies were established: full irrigation (FI), which received 100% of irrigation requirements (IR), and regulated deficit irrigation (RDI), which received 70% of IR during the whole irrigation period except during the kernel-filling stage when received 40% IR. The UAV flights were performed on four selected dates of the irrigation season. The Crop Water Status Index (CWSI) and the Normalized Difference Vegetation Index (NDVI) were derived from thermal and multispectral images, respectively, and compared to classical water status indicators, i.e., stem water potential (Ψstem), stomatal conductance (gs), and photosynthetic rate (AN). Of the four flights performed, three corresponded to mild water stress conditions and a single flight was performed under moderate water stress conditions. Under mild water stress, CWSI was not able to capture the differences between FI and RDI trees that were observed with Ψstem. Under moderate stress conditions, CWSI was sensitive to the water deficit reached in the trees and showed significant differences among both irrigation treatments. No differences were observed in the CWSI and NVDI response to water stress among cultivars. Although NDVI and CWSI were sensitive to water stress, the low signal intensity observed in NDVI makes this index less robust than CWSI to monitor crop water stress. It can be concluded that UAV-based CWSI measurements are reliable to monitor almond water status, although for early (mild) levels of water stress, Ψstem seems to be the preferred option.


2019 ◽  
Vol 37 (1) ◽  
pp. 82-88
Author(s):  
Alexandre Igor A Pereira ◽  
João de Jesus Guimarães ◽  
João Victor Costa ◽  
Fernando S de Cantuário ◽  
Leandro C Salomão ◽  
...  

ABSTRACT Water stress compromises plant growth. Resistance inducers, such as potassium silicate (K2SiO3), can reduce negative effects of this stress on Solanaceae, Capsicum annuum. Plant height, stem diameter and leaf area may indicate the efficiency of potassium silicate foliarsprayagainst water stress. The aim of this study was to evaluate the growth of sweet pepper plants under water stress and K2SiO3 doses. The experiment was conducted in randomized blocks in a split-plot scheme in space. The treatments consisted of four soil water stresses: 15 kPa (field capacity), 25 (intermediate value), 35 and 45 kPa (water stress) and three doses of potassium silicate (0, 0.4 and 0.8 L 100 L-1 water), acting as resistance inducers to water stress. The resistance inducer maintained greater heights of the sweet pepper plants, under water stress (35 and 45 kPa) at the initial stage [(20 days after transplanting (DAT)]. Smaller plant diameters were observed at 80 and 100 DAT at 35 and 45 kPa. Sprays using K2SiO3 maintained sweet pepper leaf area with higher values, even under stress condition. The soil water tension from 35 kPa limited, in general, the plant growth. Growth responses in Capsicum annuum to K2SiO3, via foliar spraying, varied according to plant age, as well as the growth parameter considered in this experiment.


2020 ◽  
Vol 44 (2) ◽  
pp. 149-162
Author(s):  
Arachchilage Kodikara ◽  
Pulukkutige Loku ◽  
Pathmasiri Ranasinghe ◽  
Madarasinghe Kanishka ◽  
Farid Dahdouh-Guebas ◽  
...  

The behaviour of carbohydrate metabolism in a plant, particularly its total starch content, total soluble sugar (TSS) content and their utilisation, is of great importance in coping with abiotic stress conditions. With this in mind, we studied total starch and TSS contents, survival, growth, biomass accumulation and stomatal conductance in Rhizophora mucronata under conditions of prolonged submergence and water stress for a period of 11 months. The experiment was designed in such a way as to include three replicates per each treatment level, about 1600 young mangrove plants being subjected to study in the process. Under conditions of prolonged submergence and high levels of water stress, a small number of mangrove plants survived and they were promptly exhausted due to higher starch utilisation rates (0.75-1.05% dry mass/month). Although TSS content was increased under these intense stress conditions, it was not matched by increased seedling growth or biomass production; instead, a significant reduction in growth (i.e., ~78%) and dry matter content was observed in stressed seedlings as compared to young plants in the respective controls. It follows that the intense increase of TSS content might be due to the direct conversion of starch to soluble sugars in order to produce metabolic energy for tolerance mechanisms like osmoregulation and root anatomical adaptations under stress conditions. This indicates that more energy is allocated for plant maintenance than for growth and biomass production under stress conditions, which might be a good acclimatory strategy to rescue young mangrove plants at the early phase. However, stomatal closure under stress conditions may have caused restricted photosynthesis. Therefore, stress-induced starch degradation may upsurge, which in turn might lead in the long-run to carbon starvation, a condition lethal to mangrove seedlings.


2003 ◽  
Vol 39 (1) ◽  
pp. 29-38 ◽  
Author(s):  
T. MATSUI ◽  
B. B. SINGH

Cowpea (Vigna unguiculata) has relatively higher drought tolerance than other legume crops. It is widely grown in semi-arid regions, particularly in West Africa. One objective of the present study was to determine the effects of soil moisture stress on the length, dry matter and distribution of the roots of two cowpea varieties with different drought tolerances. Another objective was to evaluate the pin-board root-box as a method for identifying the role of root characteristics in drought tolerance. Two cowpea varieties, IT96D-604 (drought tolerant) and TVu7778 (drought susceptible), were used in this study. There were three watering treatments, T1 (well-watered), T2 (mild water stress) and T3 (severe water stress). Between varieties, there were no significant differences in shoot and root characteristics except for leaf area in T1. Under T2, the shoot:root ratio (S:R ratio) of IT96D-604 was significantly decreased compared with that under T1 as a result of the increase in root dry matter and decrease in leaf area without significant differences in total dry matter. In addition, the root dry matter per leaf area, which indicates the capacity to absorb water, of IT96D-604 was significantly higher than that of TVu7778. Under T3, the total dry matter of TVu7778 was about one third of those of the other treatments for the same variety, whereas that of IT96D-604 was more than half. Regarding root distribution, the centres of root dry matter and root length density of both varieties moved downwards significantly under water-stress conditions compared with those of the well-watered condition. This tendency was more pronounced in IT96D-604 than in TVu7778. Drought tolerance in IT96D-604 was associated with the increase in root dry matter per leaf area under mild water-stress conditions, and downward movement of roots (increasing access and use of soil moisture in deep soil layers) under mild and severe water stress conditions. In addition, the root-box method was versatile and can be used for studying root responses to edaphic factors relevant to root growth.


1998 ◽  
Vol 3 (2) ◽  
pp. 13
Author(s):  
R. Ahmad ◽  
N. Ahmad ◽  
J.C. Stark ◽  
A. Tanveer

Yield and developmental characteristics of crop genotypes grown at different levels of water availability are often used to select genotypes that are adapted to variable moisture environments. Field studies were conducted at Aberdeen. Idaho, USA in 1992 and 1993 to evaluate the effects of varying moisture supply on grain yield and yield components of spring wheat genotypes. In both years, 12 spring wheat (Triticum aestivum L.) genotypes were grown under three irrigation levels (well-watered. moderate water-stress and severe water-stress) imposed during the periods from mid-tillering to anthesis with a line source sprinkler irrigation system. Grain yield and yield components (spikes m-2, spikelets spike-1, kernels spikelet-1,  kernels spike-1, and kernel weight) were used to evaluate the genotypic response to water stress. Overall, water stress caused a reduction in grain yield and yield components. Genotypes exhibited a large year-to-year variation in their ranks for grain yield. Medium-tall growing genotypes (IDO 367. lDO 369 and Rick) generally produced high yields under water stress conditions in 1992 (relatively dry year), while short -medium genotypes (WPB 926. Yecora Rojo and Pondera) produced high yields under water stress conditions in 1993 (relatively wet year). Chris and Serra were the lowest yielding genotypes under water stress conditions in both years. Under moderate stress conditions. 100 367 and Yecora Rojo had consistently high yields. Genotypic yield differences under water stress conditions were primarily related to the differences in the numbers of spikes m". Therefore, a tendency for high plasticity for Spikes per unit area could be used to select wheat genotypes for improved drought tolerance.


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