Differences in seedling water-stress response of two co-occurring Banksia species

In the South-west Australian Floristic Region, timing of rainfall is critical for successful seedling establishment, as is surviving the first year’s summer drought for population persistence. Predictions of a warmer, drier future, therefore, threaten the persistence of obligate seeding species. Here, we investigate the drought tolerance of two co-occurring Banksia (Proteaceae) species by withholding water in pots to different extents of soil drying. Seed was collected from high- and low-rainfall populations, to test for niche differentiation in water-use strategies at the species level, as well as population differentiation. On the basis of a more negative leaf water potential at minimal levels of stomatal conductance and quantum yield, B. coccinea was considered to be more drought tolerant than B. baxteri. This was supported at the anatomical level according to xylem-vessel attributes, with a higher estimated collapse pressure suggesting that B. coccinea is less vulnerable to xylem cavitation. Population contrasts were observed mainly for B. baxteri, with a lower leaf-expansion increment rate in the low-rainfall population providing for drought avoidance, which was reflected in a higher rate of survival than with the high-rainfall population in which 87.5% of plants showed complete leaf senescence. The implications of species differences in water-use strategies are that community dynamics may start to shift as the climate changes. Importantly, this shift may be population dependent. A systematic understanding of adaptive capacity will help inform the choice of population for use in revegetation programs, which may lead to increased resilience and persistence in the face of environmental change. The results of the present study suggest that should declines in B. baxteri populations be noted, revegetating with seed collected from the low-rainfall population may help improve the chances of this species surviving into the future.

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Grafting cv. Grechetto Gentile Vines to New M4 Rootstock Improves Leaf Gas Exchange and Water Status as Compared to Commercial 1103P Rootstock

Agronomy ◽

10.3390/agronomy10050708 ◽

2020 ◽

Vol 10 (5) ◽

pp. 708 ◽

Cited By ~ 2

Author(s):

Tommaso Frioni ◽

Arianna Biagioni ◽

Cecilia Squeri ◽

Sergio Tombesi ◽

Matteo Gatti ◽

...

Keyword(s):

Water Stress ◽

Gas Exchange ◽

Water Use ◽

Leaf Gas Exchange ◽

Water Status ◽

Stomatal Closure ◽

Leaf Water ◽

Summer Drought ◽

Co2 Uptake ◽

Drought Tolerant

M4 is a relatively new rootstock that was selected for increased resilience of vineyards across hot regions where meteorological drought is often coupled to water scarcity. However, M4 has thus far been tested only against water-stress sensitive rootstocks. Against this backdrop, the aim of the present work is to examine the water status and gas exchange performances of vines grafted to M4 in comparison to those of vines grafted to a commercial stock that is drought-tolerant, 1103 Paulsen (1103P), under a progressive water deficit followed by re-watering. This study was undertaken on Grechetto Gentile, a cultivar that is renowned for its rather conservative water use (near-isohydric behavior). While fifty percent of both grafts were fully irrigated (WW), the remaining underwent progressive water stress by means of suspending irrigation (WS). Soil and leaf water status, as well as leaf gas exchanges, along with chlorophyll fluorescence, were followed daily from 1 day pre-stress (DOY 176) until re-watering (DOY 184). Final leaf area per vine, divided in main and lateral contribution, was also assessed. While 1103P grafted vines manifested higher water use under WW conditions, progressive stress evidenced a faster water depletion by 1103P, which also maintained slightly more negative midday leaf water potential (Ψleaf) as compared to M4 grafted plants. Daily gas exchange readings, as well as diurnal assessment performed at the peak of stress (DOY 183), also showed increased leaf assimilation rates (A) and water use efficiency (WUE) in vines grafted on M4, which were also less susceptible to photosynthetic downregulation. Dynamic of stomatal closure targeted at 90% reduction of leaf stomatal conductance showed a similar behavior among rootstocks since the above threshold was reached by both at Ψleaf of about −1.11 MPa. The same fractional reduction in leaf A was reached by vines grafted on M4 at a Ψleaf of −1.28 MPa vs. −1.10 MPa measured in 1103P, meaning that using M4 as a rootstock will postpone full stomatal closure. While mechanisms involved in improved CO2 uptake in M4-grafted vines under moderate-to-severe stress are still unclear, our data support the hypothesis that M4 might outscore the performance of a commercial drought-tolerant genotype (1103P) and can be profitably used as a tool to improve the resilience of vines to summer drought.

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Exploring Smallholder Farmers’ Preferences for Climate-Smart Seed Innovations: Empirical Evidence from Southern Ethiopia

Sustainability ◽

10.3390/su13052786 ◽

2021 ◽

Vol 13 (5) ◽

pp. 2786

Author(s):

Shimelis Araya Geda ◽

Rainer Kühl

Keyword(s):

Smallholder Farmers ◽

Preference Heterogeneity ◽

Southern Ethiopia ◽

Significant Preference ◽

Experiment Data ◽

Breeding Programs ◽

Drought Tolerant ◽

The Face ◽

Mnl Model ◽

Participatory Research Methods

Rapid plant breeding is essential to overcome low productivity problems in the face of climatic challenges. Despite considerable efforts to improve breeding practices in Ethiopia, increasing varietal release does not necessarily imply that farmers have access to innovative varietal choices. Prior research did not adequately address whether varietal attributes are compatible with farmers’ preferences in harsh environmental conditions. With an agricultural policy mainly aiming to achieve productivity maximization, existing breeding programs prioritize varietal development based on yield superiority. Against this background, we estimated a multinomial logit (MNL) model based on choice-experiment data from 167 bean growers in southern Ethiopia to explore whether farmers’ attribute preferences significantly diverge from those of breeders’ priorities. Four important bean attributes identified through participatory research methods were used. The results demonstrate that farmers have a higher propensity toward drought-tolerant capability than any of the attributes considered. The model estimates further show the existence of significant preference heterogeneity across farmers. These findings provide important insight to design breeding profiles compatible with specific producer segments. We suggest demand-driven breeding innovations and dissemination strategies in order to accelerate the adoption of climate-smart and higher-yielding bean innovations that contribute to achieve the national and global sustainability goals in Ethiopia.

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Review: Response of water use efficiency to summer drought in boreal Scots pine forests in Finland

10.5194/bg-2016-198-rc4 ◽

2016 ◽

Author(s):

Anonymous

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Scots Pine ◽

Pine Forests ◽

Summer Drought ◽

Scots Pine Forests ◽

Use Efficiency

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Gibberellin in tomato: metabolism, signaling and role in drought responses

Molecular Horticulture ◽

10.1186/s43897-021-00019-4 ◽

2021 ◽

Vol 1 (1) ◽

Author(s):

Hagai Shohat ◽

Natanella Illouz Eliaz ◽

David Weiss

Keyword(s):

Tomato Plant ◽

Plant Response ◽

Water Deficiency ◽

Drought Avoidance ◽

Drought Tolerant ◽

Improved Performance ◽

Plant Life Cycle ◽

Response To Water ◽

Signaling Components

AbstractThe growth-promoting hormone gibberellin (GA) regulates numerous developmental processes throughout the plant life cycle. It also affects plant response to biotic and abiotic stresses. GA metabolism and signaling in tomato (Solanum lycopersicum) have been studied in the last three decades and major components of the pathways were characterized. These include major biosynthesis and catabolism enzymes and signaling components, such as the three GA receptors GIBBERELLIN INSENSITIVE DWARF 1 (GID1) and DELLA protein PROCERA (PRO), the central response suppressor. The role of these components in tomato plant development and response to the environment have been investigated. Cultivated tomato, similar to many other crop plants, are susceptible to water deficiency. Numerous studies on tomato response to drought have been conducted, including the possible role of GA in tomato drought resistance. Most studies showed that reduced levels or activity of GA improves drought tolerance and drought avoidance. This review aims to provide an overview on GA biosynthesis and signaling in tomato, how drought affects these pathways and how changes in GA activity affect tomato plant response to water deficiency. It also presents the potential of using the GA pathway to generate drought-tolerant tomato plants with improved performance under both irrigation and water-limited conditions.

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Questions and avenues for lucerne improvement

Czech Journal of Genetics and Plant Breeding ◽

10.17221/90/2009-cjgpb ◽

2010 ◽

Vol 46 (No. 1) ◽

pp. 1-13 ◽

Cited By ~ 15

Author(s):

P. Annicchiarico ◽

C. Scotti ◽

M. Carelli ◽

L. Pecetti

Keyword(s):

Water Conservation ◽

Forage Yield ◽

Conservation Strategy ◽

Selection Scheme ◽

Drought Avoidance ◽

Drought Tolerant ◽

Saponin Content ◽

Selection For ◽

Combined Selection ◽

Set Up

Six crucial questions for lucerne breeders are set up and discussed in relation to the available information. (i) Which width of adaptation? Genotype נlocation interaction is region-specific and may be wide enough to justify breeding for specific adaptation. Genotype נexploitation interaction requires contrasting plant types for mowing and intensive grazing. (ii) Can we breed very drought-tolerant varieties? One drought-tolerant landrace exhibited a drought-avoidance, water-conservation strategy based on limited root development, while large root featured material adapted to favourable environments and/or frequent mowing. (iii) Which selection scheme and variety type? Many schemes were proposed for synthetic varieties, but empirical or theoretical comparisons were limited in number and inference space. Non-additive genetic variation may be exploited by free hybrids (semi-hybrids) through procedures varying in complexity, possibly assisted by marker evaluation. Previous selection of exotic germplasm for adaptation is essential. (iv) How to improve the forage quality? Selection for modified stem morphology (increased internode number, decreased internode length) proved effective. Combined selection for forage yield and leaf/stem ratio seems also feasible. (v) Which opportunities for marker-assisted selection? Linkage maps for lucerne are available but useful markers for forage yield may be site-specific. Bulk segregant analysis is promising in breeding for stress tolerance. (vi) How to exploit genomic information from M. truncatula? This model species can help in developing markers and locating genes which control metabolic pathways, such as saponin content and composition. Information from M. truncatula on marker-trait association for forage yield or tolerance to abiotic stresses may be little exploitable.

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Soil water extraction by a mixed eucalypt forest during a drought period

Soil Research ◽

10.1071/sr9860025 ◽

1986 ◽

Vol 24 (1) ◽

pp. 25 ◽

Cited By ~ 21

Author(s):

T Talsma ◽

EA Gardner

Keyword(s):

Soil Water ◽

Water Use ◽

Water Table ◽

Unsaturated Flow ◽

Growth Ring ◽

Soil Water Potential ◽

Water Extraction ◽

Depth Interval ◽

Summer Drought ◽

Drought Period

Eucalypt trees growing on deep soils, with a water table at about 8 m depth, showed no apparent drought effects during the 1982-83 dry period in south-east Australia when gross precipitation was only 388 mm. At the end of the drought, soil water to 4 m depth was depleted to a soil water potential of -0.5 MPa and under these conditions unsaturated flow from the water table to the lower root zone was calculated to be 0.17 mm day-1. Water extraction over the depth interval from 0 to 6 m in the drought year was 533 mm, some 200 mm in excess of that used during a year of average rainfall. The contribution to tree water use from unsaturated flow from the water table was calculated to be small (15 mm) even in a drought year, and in most years water movement would be towards the water table to yield a deep drainage term estimated between 40 and 100 mm. Growth ring studies indicated that the lower water use, estimated at 2.6 mm day-1 during the spring-summer drought, did not affect the slowly growing E. radiata species, but reduced stem diameter growth of the faster growing E. dalrympleana and E. pauciflora species.

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Screening for Drought Tolerance in Thirty Three Taro Cultivars

Notulae Botanicae Horti Agrobotanici Cluj-Napoca ◽

10.15835/nbha46110950 ◽

2018 ◽

Vol 46 (1) ◽

pp. 65-74 ◽

Cited By ~ 8

Author(s):

José F.T. GANANÇA ◽

José G.R. FREITAS ◽

Humberto G.M. NÓBREGA ◽

Vanessa RODRIGUES ◽

Gonçalo ANTUNES ◽

...

Keyword(s):

Drought Tolerance ◽

Agronomic Traits ◽

Yield Stability ◽

Yield Potential ◽

High Yield ◽

Potential Yield ◽

Local Cultivars ◽

Drought Avoidance ◽

Drought Tolerant ◽

Long Duration

Taro [Colocasia esculenta (L.) Schott] is a root crop which is an important staple food in many regions of the world, producing 10.5 million tonnes on 1.4 million hectares a year. The crop is cultivated in wet (rain fed) or irrigated conditions, requiring on average 2,500 mm water per year, and in many countries it is cultivated in flooded plots. It is estimated that taro production could decrease by 40% as a result of the increase in drought and other severe events. In this work, thirty three accessions, including local cultivars, selected and hybrid lines were submitted to long duration drought stress and screened for tolerance. Twelve physiological, morphological and agronomic traits were measured at harvest, and subject to multivariate analysis. Stress indices, Water Use Efficiency and Factorial Analysis were useful for discriminating accessions regarding drought tolerance and yield stability, and drought tolerant and susceptible cultivars were identified. Our results confirm that different taro cultivars have different drought avoidance and tolerance strategies to cope with water scarcity. Better yield performers minimised biomass and canopy loss, while tolerance was observed in cultivars that presented low potential yield, but efficiently transferred resources to enhance corm formation. Among the 33 accessions, two local cultivars showed high yield stability and could be considered as suitable parents for breeding programs, while two others are well adapted to drought, but with overall low yield potential.

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Effects of Drought Frequency on Growth Performance and Transpiration of Young Black Locust (Robinia pseudoacaciaL.)

International Journal of Forestry Research ◽

10.1155/2014/821891 ◽

2014 ◽

Vol 2014 ◽

pp. 1-11 ◽

Cited By ~ 12

Author(s):

Dario Mantovani ◽

Maik Veste ◽

Dirk Freese

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Water Use Efficiency ◽

Growth Performance ◽

Water Use ◽

Water Availability ◽

Black Locust ◽

Marginal Land ◽

Drought Tolerant ◽

Use Efficiency

Black locust (Robinia pseudoacaciaL.) is a drought-tolerant fast growing tree, which could be an alternative to the more common tree species used in short-rotation coppice on marginal land. The plasticity of black locust in the form of ecophysiological and morphological adaptations to drought is an important precondition for its successful growth in such areas. However, adaptation to drought stress is detrimental to primary production. Furthermore, the soil water availability condition of the initial stage of development may have an impact on the tree resilience. We aimed to investigate the effect of drought stress applied during the resprouting on the drought tolerance of the plant, by examining the black locust growth patterns. We exposed young trees in lysimeters to different cycles of drought. The drought memory affected the plant growth performance and its drought tolerance: the plants resprouting under drought conditions were more drought tolerant than the well-watered ones. Black locust tolerates drastic soil water availability variations without altering its water use efficiency (2.57 g L−1), evaluated under drought stress. Due to its constant water use efficiency and the high phenotypic plasticity, black locust could become an important species to be cultivated on marginal land.

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