scholarly journals Morphological responses of seedlings of four species of Salicaceae to drought

1996 ◽  
Vol 74 (12) ◽  
pp. 1988-1995 ◽  
Author(s):  
I. Van Splunder ◽  
L. A. C. J. Voesenek ◽  
X. J. A. De Vries ◽  
C. W. P. M. Blom ◽  
H. Coops
Keyword(s):  
Drought Resistance ◽  
Root Length ◽  
Distribution Patterns ◽  
Water Levels ◽  
Salix Viminalis ◽  
River Rhine ◽  
Growth Responses ◽  
Salix Alba ◽  
Soil Layers ◽  
River Banks

The riparian distribution patterns of floodplain species are affected by fluctuations in water level. Rapidly declining water levels in river banks during the growing period of plants can result in limited availability of water, particularly on coarse substrates. Differences in drought resistance among Salix alba, Salix triandra, Salix viminalis, and Populus nigra, four species dominating river banks along the River Rhine, could explain part of the riparian distribution patterns. Mortality and growth responses of seedlings grown under well-watered and dry conditions were studied in a greenhouse experiment. Drought-induced mortality was 0% in S. alba and P. nigra, 37.5% in S. triandra, and 62.5% in S. viminalis, which correlated with differences in water-loss characteristics of the species studied: S. triandra and S. viminalis had much higher transpiration rates under well-watered conditions than S. alba and P. nigra. Decreased shoot to root ratios were observed in all species after 3 weeks of drought. The increase after drought of the root length to leaf area ratio was greatest for P. nigra, indicating that this species has a relatively efficient water economy. Specific leaf areas of draughted plants decreased in S. alba and P. nigra, reflecting smaller transpiration areas. Drought also affected root distributions, resulting for all four species in deeper rooting and increased root length in deeper soil layers. Salix viminalis and S. triandra showed the greatest increase in root length in deep soil layers. We concluded that P. nigra is most resistant to drought followed by S. alba and then S. triandra and S. viminalis, and that these differences are reflected in the distribution patterns of these species observed on the banks of the River Rhine. Keywords: drought resistance, Salix, Populus, root distribution, transpiration, leaf conductance.

scholarly journals Genotypic variation in root distribution changes and physiological responses of sugarcane induced by drought stress

2018 ◽  
Author(s):  
Jariya Namwongsa ◽  
Nuntawoot Jongrungklang ◽  
Patcharin Songsri
Keyword(s):  
Drought Stress ◽  
Stomatal Conductance ◽  
Drought Resistance ◽  
Root Length ◽  
Root Distribution ◽  
Physiological Traits ◽  
Growth Stages ◽  
Research Station ◽  
Soil Layers ◽  
Khon Kaen

Drought is an important factor reducing yield and quality of sugarcane. Root growth and physiological traits are important for maximizing water uptake to improve drought resistance. This study compared the root, shoot and physiological traits under drought stress (DS) and well-watered (WW) conditions of various sugarcane varieties grown in rhizoboxes in a greenhouse at the Field Crops Research Station of Khon Kaen University, Khon Kaen, Thailand. Data were recorded for the root, shoot and physiological traits (relative water content, stomatal conductance, SPAD chlorophyll meter reading and chlorophyll fluorescence) at 90 days after transplanting. Root samples were recovered from 11 soil layers at 10 cm intervals from the top to the bottom of the rhizobox, for root length and root dry weight measurements. Drought was imposed on sugarcane at early growth stages altered the root distribution patterns, and differences were evident among the sugarcane genotypes. The sugarcane genotypes adapted to water stress by increasing root length into deeper soil layers. Drought led to increased total root length in KK3, MPT06-166, K88-92, CP38-22, Kps01-12 and KPK98-40. Root lengths and stomatal conductance were positively correlated under WW and DS conditions. Root distribution in the lower soil layers and the percentage of root distribution were higher than those under well-watered conditions. The knowledge gained from this study will aid parental selection in sugarcane breeding programs for drought resistance as the findings strongly suggest that the physiological modification in the root system is a useful drought-resistant mechanism.

Root production, mortality and turnover in soil profiles as affected by clipping in a temperate grassland on the Loess Plateau

2019 ◽  
Vol 12 (6) ◽  
pp. 1059-1072
Author(s):  
Lin Wei ◽  
Pengwei Yao ◽  
Guanghua Jing ◽  
Xiefeng Ye ◽  
Jimin Cheng
Keyword(s):  
Loess Plateau ◽  
Soil Profile ◽  
Root Length ◽  
Root Biomass ◽  
Turnover Rate ◽  
Fine Root ◽  
Root Production ◽  
The Loess Plateau ◽  
Soil Layers ◽  
Root Mortality

Abstract Aims Clipping or mowing for hay, as a prevalent land-use practice, is considered to be an important component of global change. Root production and turnover in response to clipping have great implications for the plant survival strategy and grassland ecosystem carbon processes. However, our knowledge about the clipping effect on root dynamics is mainly based on root living biomass, and limited by the lack of spatial and temporal observations. The study aim was to investigate the effect of clipping on seasonal variations in root length production and mortality and their distribution patterns in different soil layers in semiarid grassland on the Loess Plateau. Methods Clipping was performed once a year in June to mimic the local spring livestock grazing beginning from 2014. The minirhizotron technique was used to monitor the root production, mortality and turnover rate at various soil depths (0–10, 10–20, 20–30 and 30–50 cm) in 2014 (from 30 May to 29 October) and 2015 (from 22 April to 25 October). Soil temperature and moisture in different soil layers were also measured during the study period. Important Findings Our results showed that: (i) Clipping significantly decreased the cumulative root production (P < 0.05) and increased the cumulative root mortality and turnover rates of the 0–50 cm soil profile for both years. (ii) Clipping induced an immediate and sharp decrease in root length production and an increase in root length mortality in all soil layers. However, with plant regrowth, root production increased and root mortality decreased gradually, with the root production at a depth of 30–50 cm even exceeding the control in September–October 2014 and April–May 2015. (iii) Clipping mainly reduced root length production and increased root length mortality in the upper 0–20 cm soil profile with rapid root turnover. However, roots at deeper soil layers were either little influenced by clipping or exhibited an opposite trend with slower turnover rate compared with the upper soil profile, leading to the downward transport of root production and living root biomass. These findings indicate that roots in deeper soil layers tend to favour higher root biomass and longer fine root life spans to maximize the water absorption efficiency under environmental stress, and also suggest that short-term clipping would reduce the amount of carbon through fine root litter into the soil, especially in the shallow soil profile.

scholarly journals Above and Belowground Growth of Corymbia maculata in a Constructed Soil: The Effect of Profile Design and Organic Amendment

2010 ◽  
Vol 36 (1) ◽  
pp. 11-17
Author(s):  
Karen Smith ◽  
Peter May ◽  
Robert White
Keyword(s):  
Organic Matter ◽  
Root Length ◽  
Organic Amendment ◽  
Root Length Density ◽  
Dry Weight ◽  
Nutrient Status ◽  
Fertilizer Treatment ◽  
Coir Fiber ◽  
Growth Responses ◽  
Profile Design

Spotted gum (Corymbia maculata (Hook.) K.D. Hill & L.A.S. Johnson), a common street tree in southern Australian cities, was used to assess growth responses to variations in profile design and organic amendment of constructed soils. Aboveground growth responses were total stem dry weight and foliar nutrient content. The belowground response was root length density. Soil profiles were constructed of sand, amended with either coir fiber, composted biosolids or composted green waste, at rates of 0, 5, 10 or 20% by volume. The profiles were either layered, with a 150 mm (6 in) organic-amended surface layer, or uniform, with amendment of the entire profile. A single fertilizer treatment was applied to all profiles. Shoot dry weight was only affected by organic matter type with the greatest growth in sand amended with composted biosolids. Foliage P and K content were affected by amendment but foliage N was not. Profile design affected root length density and distribution. Trees in uniform profiles had greater root length density, and a more uniform distribution of roots, especially with compost amendments. Above- and belowground growth increases are thought to be due to increased nutrient status resulting from organic matter mineralization.

scholarly journals The Effects of Water Levels and Interspecific Competition on Two Carex Species in a Temperate Wetland of Northeast China

2020 ◽  
Vol 12 (24) ◽  
pp. 10654
Author(s):  
Wenwen Tan ◽  
Li Sun ◽  
Xinhou Zhang ◽  
Changchun Song
Keyword(s):  
Spatial Distribution ◽  
Water Level ◽  
Interspecific Competition ◽  
Distribution Patterns ◽  
Wetland Plants ◽  
Water Levels ◽  
Carex Lasiocarpa ◽  
Temperate Wetland ◽  
The Relationship ◽  
Spatial Distribution Characteristic

Zonation along a water level is the main spatial distribution characteristic of wetland plants. This is mainly because of the influences of hydrological conditions and interspecific competition, which finally narrow the fundamental niche of a species to its realized niche. In the present study, a controlled experiment was conducted in order to analyze the relationship between Carex lasiocarpa/Carex pseudocuraica and Glyceria spiculosa, in conditions of three competitive treatments at four water levels. The results showed that in no competition, C. lasiocarpa preferred low water levels, but this preference receded when competing with G. spiculosa. In contrast, C. pseudocuraica had greater preference for low water level when competing with G. spiculosa. The root/shoot ratios of the two Carex species decreased with increasing water levels, but they were almost unaffected by different competition treatments. With the increase in water level during full competition with G. spiculosa, the competitive ability of C. lasiocarpa showed an increasing trend, whereas a contrary trend was observed in C. pseudocuraica. Our results suggested the effects of water levels and their interactions with interspecific competition varied between the two Carex species and played an important role in determining spatial distribution patterns and potential community succession of wetland plants.

scholarly journals Barley shoot biomass responds strongly to N:P stoichiometry and intraspecific competition, whereas roots only alter their foraging

2020 ◽  
Vol 453 (1-2) ◽  
pp. 515-528 ◽  
Author(s):  
Amit Kumar ◽  
Richard van Duijnen ◽  
Benjamin M. Delory ◽  
Rüdiger Reichel ◽  
Nicolas Brüggemann ◽  
...  
Keyword(s):  
Root System ◽  
Intraspecific Competition ◽  
Root Length ◽  
Root Biomass ◽  
Specific Root Length ◽  
Plant Performance ◽  
Shoot Biomass ◽  
P Availability ◽  
Soil Layers ◽  
N:P Stoichiometry

Abstract Aims Root system responses to the limitation of either nitrogen (N) or phosphorus (P) are well documented, but how the early root system responds to (co-) limitation of one (N or P) or both in a stoichiometric framework is not well-known. In addition, how intraspecific competition alters plant responses to N:P stoichiometry is understudied. Therefore, we aimed to investigate the effects of N:P stoichiometry and competition on root system responses and overall plant performance. Methods Plants (Hordeum vulgare L.) were grown in rhizoboxes for 24 days in the presence or absence of competition (three vs. one plant per rhizobox), and fertilized with different combinations of N:P (low N + low P, low N + high P, high N + low P, and high N + high P). Results Shoot biomass was highest when both N and P were provided in high amounts. In competition, shoot biomass decreased on average by 22%. Total root biomass (per plant) was not affected by N:P stoichiometry and competition but differences were observed in specific root length and root biomass allocation across soil depths. Specific root length depended on the identity of limiting nutrient (N or P) and competition. Plants had higher proportion of root biomass in deeper soil layers under N limitation, while a greater proportion of root biomass was found at the top soil layers under P limitation. Conclusions With low N and P availability during early growth, higher investments in root system development can significantly trade off with aboveground productivity, and strong intraspecific competition can further strengthen such effects.

scholarly journals Effects of Arbuscular Mycorrhizal Fungi on Growth and Physiological Performance of Catalpa bungei C.A.Mey. under Drought Stress

Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1117
Author(s):  
Wei Chen ◽  
Panpan Meng ◽  
Huan Feng ◽  
Chunyan Wang
Keyword(s):  
Drought Stress ◽  
Drought Resistance ◽  
Water Status ◽  
Photosynthetic Pigment ◽  
Arbuscular Mycorrhizal ◽  
Northwest China ◽  
Water Levels ◽  
Timber Species ◽  
Physiological Performance ◽  
Catalpa Bungei

Catalpa bungei C.A.Mey. is a common ornamental timber species. Its survival and growth are greatly affected by water scarcity in arid and semi-arid areas of Northwest China. Evidence suggests arbuscular mycorrhizal fungus (AMF) may improve plant drought resistance. However, there is limited information on the systematic effects of AMF on drought resistance in C. bungei seedlings. Here, a pot experiment was used to explore the effects of inoculation with the AMF Rhizophagus intraradices on the growth and physiological performance of C. bungei under different water treatment conditions. Three water levels and two mycorrhizal inoculation treatments were used with factorial design. The results showed that drought stress noticeably affected the growth and physiological performance of C. bungei seedlings. However, inoculation with R. intraradices significantly ameliorated the growth, and alleviated the effects of drought stress. The growth parameters of AMF-inoculated seedlings significantly increased regardless of water status. AMF changed the biomass allocation in seedlings by reducing the root mass ratio (RMR) and root/shoot ratio. AMF-inoculated seedlings displayed higher gas exchange parameters, photosynthetic pigment concentrations, specific leaf area (SLA), but lower specific leaf weight (SLW), regardless of water status. AMF alleviated drought-induced oxidative stress by attenuating the excess generation of reactive oxygen species (ROS), especially H2O2 and O2−, in leaves. Inoculation with AMF under drought stress also dramatically augmented indole-3-acetic acid (IAA) and gibberellins (GA3) levels and the IAA/abscisic acid (ABA) and GA3/ABA ratios, but reduced ABA and zeatin (ZT) levels in leaves. AMF symbiosis improved root morphology and promoted the absorption of nitrogen (N) and phosphorus (P) in seedlings. We conclude that inoculation with R. intraradices is potentially useful for afforestation and cultivation of C. bungei in Northwest China. Furthermore, AMF improved soil structure by increasing the glomalin-related soil protein (GRSP) contents and the proportion of macro-aggregates (0.25–0.5 mm) in the rhizosphere soil.

scholarly journals Physiological tolerance to drought under high temperature in soybean cultivars

2019 ◽  
pp. 976-987 ◽  
Author(s):  
Jônatas Neves de Castro ◽  
Caroline Müller ◽  
Gabriel Martins Almeida ◽  
Alan Carlos Costa
Keyword(s):  
High Temperature ◽  
Water Deficit ◽  
Electron Flow ◽  
Soluble Sugar ◽  
Water Levels ◽  
Effective Quantum Yield ◽  
Growth Responses ◽  
Ps Ii ◽  
Total Electron ◽  
Soybean Cultivars

Soybean is one of the most economically important crops and has experienced adverse physiological and biochemical effects when subjected to drought stress and heat, resulting in lost productivity. Thus, the objective of this work was to evaluate the physiological, metabolic and growth responses of well-watered and drought-treated soybean cultivars under high temperature. The experimental design was set up in randomized blocks, in a factorial scheme with three soybean cultivars (7739 M, Anta 82 and Desafio) and two water levels (100% and 40% field capacity). The experiment was conducted in a controlled growth chamber with a gradual rise in temperature at 41°C for 5 hours daily. Morpho-physiological and metabolic analyses were performed 12 days after the treatments imposition. The parameters of water and osmotic potentials, relative water content, photosynthetic rate, stomatal conductance, transpiratory rate, electron flux for the carboxylation and oxygenation of RuBisCO were decreased for all cultivars under water deficit and high temperature. The results showed that the photorespiration and the rate of electrolyte leakage were increased as well. These results showed that these physiological behaviors are standard for soybean plants under water deficit, regardless of cultivars. The cultivars 7739 M and Desafio showed lower performance than the cultivar Anta 82 for the parameters of total electron flow and effective quantum yield of PS II. The 7739 M and Anta 82 were the only cultivars to show increased non-photochemical quenching dissipation and total soluble sugar content, respectively, under stress conditions. Desafio cultivar demonstrated greater physiological and growth traits stability, which could potentially indicate double tolerance to these stresses.

scholarly journals Possibility of reusing Al-Machraya River for feeding Hawizeh marsh

2018 ◽  
Vol 162 ◽  
pp. 03004 ◽  
Author(s):  
Mahmoud Al-Khafaji ◽  
Hayder Al Thamiry ◽  
Ala Al-Saedi
Keyword(s):  
Water Level ◽  
Distribution Patterns ◽  
Water Levels ◽  
Type I ◽  
Normal Type ◽  
Distribution Models ◽  
Type Iii ◽  
Tigris River ◽  
Pearson Type ◽  
Log Normal

Al Machraya River was considered as one of the water feeders of Hawizeh Marsh. In 1986, the outlet of this river into the marsh was blocked and the river was used as a main channel for the East Tigris Irrigation Project near Kalat Salih. This causes significant decrease in the available water supply sources, deterioration in the water quality distribution patterns and increasing the stagnation areas within the marsh. This research aims to study the possibility of reusing this river for feeding Hawizeh Marsh. A frequency analysis study was carried out to study the maximum and minimum probable water level (MMPWL) of Tigris River at the upstream of Kalat Salih Barrage. Six statistical models; Normal distribution, Log-Normal type II, Log-Normal type III, Pearson type III, Log- Pearson type III and Gumbel type I distribution were used to estimate the MMPWL. The results show that Pearson type III and Gumbel type I distribution models are the best to fit the maximum and minimum daily water level (WL), respectively, at the upstream of the Barrage. The estimated MMPWL were compared to the required WL in Hawizeh Marsh. The difference between Tigris River and Hawizeh Marsh water levels were found to be not operative to cause a significant flow toward the marsh. Therefore, Al Machraya River cannot be used to feed Hawizeh Marsh.

Root and Shoot Responses to Salt Stress in Jojoba (Simmondsia chinensis)

2020 ◽  
Author(s):  
Jhonathan Ephrath ◽  
Alon Ben-Gal ◽  
Amnon Bustan ◽  
Lina Zhao
Keyword(s):  
Plant Growth ◽  
Root Length ◽  
Root Length Density ◽  
Soil Depth ◽  
Distribution Patterns ◽  
Root Diameter ◽  
Salinity Level ◽  
Simmondsia Chinensis ◽  
Root Number ◽  
Over Time

&lt;p&gt;Salinity affects plant growth due to both osmotic and ionic stress. The root system is essential in defense mechanisms against salinity, particularly involving salt ion avoidance or exclusion. Jojoba (&lt;em&gt;Simmondsia chinensis&lt;/em&gt;) displays significant resistance to salinity. In the present study, Jojoba was planted in 60-L plastic buckets containing perlite growth medium and were provided with eight distinct salinity levels using two operating tanks of final irrigation solutions. Response of Jojoba to salinity was measured in above ground parameters and in roots using minirhizotron access tubes and imaging analysis. Leaf phosphorous and potassium concentrations decreased with increasing salinity level while leaf manganese, calcium, sodium and chloride concentrations increased with irrigation salinity level. Jojoba plants were found to have high level of storage of salt minerals in leaves but without effects on photosynthesis or transpiration. Roots exhibited different distribution patterns under different salinity treatments. Root length density increased with increased salinity at each depth. Root number and root length increased over time. During spring, the plant growth was faster than winter. Root diameter decreased over time due to new root development. Time had a more significant effect on root length density than irrigation water salinity or soil depth. Root number and root length were not significantly affected by the salt treatments.&lt;/p&gt;

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