scholarly journals Water extraction under terminal drought explains the genotypic differences in yield, not the anti-oxidant changes in leaves of pearl millet (Pennisetum glaucum)

2013 ◽  
Vol 40 (1) ◽  
pp. 44 ◽  
Author(s):  
Jana Kholová ◽  
Vincent Vadez

Pearl millet (Pennisetum glaucum (L.) R.Br.) is a resilient crop suiting the harshest conditions of the semi-arid tropics, in which we assessed possible relationships between crop tolerance, anti-oxidative enzyme activity and plant/soil water status. Biochemical acclimation and cell homeostasis traits have been proposed as critical for the drought tolerance of crops, but their limited practical application in breeding so far suggests that the role of biochemical acclimation for drought tolerance is still unclear. Previous research may have been of limited value because it has not approached biochemical acclimation from the angle of plant water relations. Four pearl millet genotypes, contrasting for terminal drought tolerance, were evaluated (sensitive H77/833–2, tolerant PRLT2/89–33 and two near isogenic lines carrying a terminal drought tolerance quantitative trait locus) under water-stress (WS) and well-watered (WW) conditions in a lysimetric system that simulates field-like conditions. We assessed the genotypic variation and relationship between photosynthetic pigments (chlorophylls a and b and carotenoids), antioxidative isoenzymatic spectrum (superoxide dismutase, ascorbate peroxidase and catalase), physiological traits (soil moisture available, normalised transpiration, stay-green score and water extraction) and biomass and yield. Biochemical traits investigated were tightly related among each other under WS conditions but not under WW conditions. Two major ascorbate peroxidase isoforms (APX6&7), whose variation in both water regimes reflected the presence/absence of the drought tolerance quantitative trait locus, were identified, but these did not relate to yield. Both, yield and biochemical traits under terminal drought stress were closely related to the traits linked to plant/soil water status (soil moisture available, normalised transpiration, stay-green score and water extraction), whereas yield and the biochemical indicators were not correlated, except for one. It is concluded that there is no direct effect of biochemical traits on yield parameters since both are consequences of soil-plant water status and their putative relation appear to be secondary – through plant/soil water status.

2016 ◽  
Vol 19 (7) ◽  
pp. 1776-1787 ◽  
Author(s):  
Özgür Tatar ◽  
Angel Konakchiev ◽  
Tsonko Tsonev ◽  
Violeta Velikova ◽  
Emilia Gesheva ◽  
...  

2021 ◽  
Author(s):  
Sandra María Martínez-Pedreño ◽  
Pablo Berríos ◽  
Abdelmalek Temnani ◽  
Susana Zapata ◽  
Manuel Forcén ◽  
...  

<p>In water scarcity areas, it is necessary not only reducing the water applied as much as possible, but also optimizing nutrients application to avoid soil salinization and aquifers pollution because of leaching bellow the root zone. Increasing the sustainability of fertirrigation needs technology to adjust the irrigation time, knowing more precisely the soil water retention capacity and facilitate water absorption by the crop. The aim of this trial was to establish protocols for sustainable fertirrigation in melon crop under semi-arid conditions, both at an environmental and economic level, based on the use of soil water status indicators measured by sensors that allow us to increase the irrigation water use efficiency. Two irrigation treatments were established: i) Control (CTL), irrigated to satisfy the water requirements of the crop, according to the farmer's criterion throughout the crop cycle and ii) DI, deficit irrigation, irrigated to allow a maximum soil water depletion of 20%, with respect to field capacity throughout the crop cycle, from sensors located below the 20 cm depth horizon, in order to limit water leaching into the soil. An experimental design was established with 4 repetitions per treatment distributed at random, with 5 plants per repetition. Macro and micronutrients concentration of soil solution, leaves and fruits were analysed. The crop water status was determined fortnightly by measurements taken at solar midday of stem water potential, net photosynthesis, evapotranspiration rate and leaf conductance. Whereas photosynthetically active radiation absorption, basal stem and fruit equatorial diameters were determined to estimate plant and fruit growth. The physical (longitudinal and equatorial fruit diameters, fruit weight, pulp width and firmness) and chemical (titratable acidity, pH and total soluble solid of the juice, total phenolic content, total antioxidant capacity and total ascorbic acid) characteristics of harvested fruits were determined. Total water applied in CTL treatment was 3,254 m<sup>3</sup> ha<sup>-1</sup> throughout the crop cycle whereas DI received 2,284 m<sup>3</sup> ha<sup>-1</sup>, a 29.8% lower. In both cases, the volume of water applied was lower than recommended by FAO. The regulation of the irrigation time in the DI treatment respect to the CTL promoted a reduction of the soil water content from 30 cm depth, mitigating the water loss below the root system, along with a lower contribution of nutrients, around of 43, 41.8 and 22% of N, P and K, respectively, and less salinization of the soil profile. No significant difference between treatments was detected in the concentration of these nutrients at leaf level. No difference was observed at harvest, with 0.53 and 0.59 g fruit g<sup>-1</sup> total dry mass of harvest index in CTL and DI, respectively. Fruit quality was not negatively affected in DI but improved since ascorbic acid was higher. This means that DI treatment not only did not negatively affect the crop water status and the amount and quality of the yield, but also improved its biochemical quality while reducing water and nutrients use and leaching.</p>


2020 ◽  
Vol 290 ◽  
pp. 107988
Author(s):  
Fei Li ◽  
Guibiao Yang ◽  
Yunfeng Peng ◽  
Guanqin Wang ◽  
Shuqi Qin ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document