Water deficits change dry matter partitioning and seed yield in narrow-leafed lupins (Lupinus angustifolius L.)

1991 ◽  
Vol 42 (3) ◽  
pp. 471 ◽  
Author(s):  
RJ French ◽  
NC Turner

lrrigation treatments were imposed in the field on an indeterminate cultivar of narrow-leafed lupins (Lupinus angustifolius L., cv. Danja) and on a breeding line with reduced branching (75A/329) so that they experienced no water-deficits (frequently irrigated), a transient mild water-deficit or a transient severe water-deficit during early reproductive growth, or continuous severe water-deficit during reproductive growth (unirrigated). Both leaf water potential and leaf conductance declined in all treatments in which a water-deficit was imposed. Differences in leaf conductance were apparent before differences in leaf water potential: conductance declined to 40% and 30% of the frequently irrigated controls in the transient mild and severe water-deficit treatments, respectively. Leaf water potential declined to -1 - 1 MPa and -1.6 MPa, respectively, in the transient mild and severe water-deficit treatments, compared to between -0 - 65 and -0 - 95 MPa for the frequently irrigated controls. Seed yield and total dry weight were reduced in the transient severe water-deficit and unirrigated treatments, but were no different from the frequently irrigated treatment when the water-deficit was transient and mild. However both transient water-deficit treatments produced more main-stem seed yield than the frequently irrigated treatment, especially in the reduced-branching line 75A/329. The transient mild water-deficit treatment also produced more first-order apical axis yield than the frequently irrigated treatment. These yield increases were mainly due to a greater yield of seed per pod, although on the first-order apical axes there was also a tendency to set more pods. The greater seed yield per pod in the transient water-deficit treatments was due to an apparent redirection of assimilate from vegetative to reproductive growth. This was not due to a smaller reduction in reproductive growth rates than in vegetative growth rates, but to an acceleration of reproductive growth that was maintained after stress relief. The same early acceleration of reproductive growth was also observed in unirrigated treatments, but the severe stress which persisted throughout later reproductive growth reduced pod growth rates and negated the early advantage.

1999 ◽  
Vol 50 (7) ◽  
pp. 1225 ◽  
Author(s):  
J. A. Palta ◽  
Z. Plaut

The effect of transient water deficits on seed yield and components of seed yield of narrow-leafed lupin was measured in plants grown in a controlled environment under simulated field conditions. Lupins were grown in large columns of soil and transient water deficits were induced at pod set on the mainstem and first-order apical branches by withholding water for a 5-day period. Soil water content, leaf water potential, turgor pressure, and leaf conductance declined similarly during each period of transient water deficit. Differences in these parameters were apparent 2 days after water was withheld, and over the 5-day period, leaf water potential declined to −1.3 MPa and leaf conductance fell to 44% of the well-watered controls. Total dry matter per plant was reduced by the transient water deficit treatments. The reduction resulted from less accumulation of dry matter on the first, second, and third order apical branches. Leaf area on these branches was also reduced by abscission of the leaves after the water deficit was released. Seed yield per plant after each period of transient water deficit was reduced by 30–33%, relative to the well-watered controls. The reduction was largely due to a reduction in seed yield on the branches, mainly because they had fewer pods and seeds per pod. Seed dry weight and harvest index were not significantly affected by each period of transient water deficit. We conclude that differences in final seed yield between the well- watered controls and the transient water deficit treatments resulted from differences in pod number and seeds per pod. Low dry matter accumulation and reduction in leaf area on the first- and second-order apical branches under the transient water deficit were associated with the differences. Whereas the differences in pod number generated differences in the size of the reproductive sink, the differences in leaf area generated differences in the source capacity for assimilates for pod set and pod-filling.


OENO One ◽  
2000 ◽  
Vol 34 (4) ◽  
pp. 169
Author(s):  
Xavier Choné ◽  
Olivier Trégoat ◽  
Cornelis Van Leeuwen ◽  
Denis Dubourdieu

<p style="text-align: justify;">Vine water status is an important factor in grape quality. High tannin and anthocyanin content in red grape berries are related to moderate vine water deficits. Hence, a simple and sensitive indicator is required to determine vine water status and especially water constraint. Pressure chamber allows a quick and easy to practice determination of water status in the vineyard. Three applications of pressure chamber are known: predawn leaf water potential (ΨB), leaf water potential (ΨF) and stem water potential (ΨT). Only ΨB and ΨF are widely used on vines. In this survey ΨB, ΨF, ΨT and transpiration flow were measured on mature leaves to determine non-irrigated vine water status in field grown vines during the growing season. In California as well as in France, stem Ψ was the most discriminating indicator for both moderate and severe water deficits. In every plot surveyed ΨT was much better correlated to leaf transpiration than ΨF. Moreover, ΨT revealed nascent water deficit earlier than ΨB did. Among the three application of pressure chamber, ΨT was the only one to indicate short term water deficit after a rainfall. Hence, ΨT appears to be a useful indicator for grapevine management in both non-irrigated and irrigated vineyards.</p>


2020 ◽  
Vol 79 (1) ◽  
pp. 87-94
Author(s):  
Leila Romdhane ◽  
Nicola Dal Ferro ◽  
Amor Slama ◽  
Leila Radhouane

Rising temperatures and increasing water scarcity, which are already important issues, are expected to intensify in the near future due to global warming. Optimizing irrigation in agriculture is a challenge. Understanding the response of crop development stages to water deficit stress provides an opportunity for optimizing irrigation. Here we studied the response of two barley varieties (Rihane, Martin), to water deficit stress at three development stages (tillering, stem elongation, and heading) by measuring water status and grain yield components in a field experiment in Tunisia. The three stages were selected due to their importance in crop growth and grain development. Water deficit stress was initiated by withholding water for 21 days at the three stages with subsequent re-watering. Water deficit led to a progressive decrease in leaf water potential. In both varieties, heading was the stage most sensitive to water deficit. Leaf water potential measurements indicated that water deficit stress was more severe during heading, which to some extent may have influenced the comparison between growth stages. During heading, the number of ears per plant and weight of a thousand grains were reduced by more than 70% and 50%, respectively compared with stress at tillering. Comparison of yield components showed differences between the two barley varieties only when the water deficit was produced during the tillering stage.


1991 ◽  
Vol 42 (5) ◽  
pp. 747 ◽  
Author(s):  
T Tangpremsri ◽  
S Fukai ◽  
KS Fischer ◽  
RG Henzell

Development of genotypic variation in osmotic adjustment was examined in two glasshouse experiments using two sets of sorghum material. In the first experiment, 47 S2 lines extracted from a randomly mated population were used, whereas in the other, inbred parents and their 15 hybrids were compared. In both experiments, water deficit was induced in two periods, one before anthesis and the other after anthesis for most genotypes. In both experiments osmotic potential at the beginning of the first drying period was similar among genotypes and therefore osmotic potential obtained under water deficit was used for the comparison of osmotic adjustment among genotypes. In the first drying period of both experiments, when stress was milder, about 40% of the variation in osmotic adjustment was accounted for by difference in leaf water potential. When the effect of water potential was removed by covariance analysis, there was significant genotypic variation in osmotic adjustment in the second experiment, but not in the first experiment. On the other hand, in the second drying period, when stress was more severe, the effect of leaf water potential on osmotic adjustment was small. There was significant genotypic variation in osmotic adjustment in both experiments after the water potential effect was removed by covariance analysis. Osmotic adjustment in the second drying period was also negatively correlated with grain sink/source ratio (number of grains/leaf area) in the first set of materials. The comparison of osmotic adjustment among hybrids and their parents showed that, in this particular set of genotypes, the female parents were more important than the male in determining osmotic adjustment of the hybrids. The genotypic variation was associated with performance under water deficit in the field. It is concluded that there is considerable genotypic variation in osmotic adjustment in the genetic material examined. Osmotic adjustment is, however, correlated with water potential and grain sink/source balance, and hence the selection for osmotic adjustment needs to ensure that high value is not due simply to low water potential or small head size.


2014 ◽  
Vol 4 (2) ◽  
Author(s):  
Song Ai Nio ◽  
Audry Agatha Lenak

Abstrak Penggulungan daun merupakan salah satu bentuk resistensi terhadap kekeringan atau lebih tepatnya mekanisme menghindari kekeringan pada tumbuhan monokotil. Mekanisme ini terjadi dengan cara menurunkan laju evapotranspirasi atau dengan meningkatkan absorpsi air pada tanah kering untuk mempertahankan potensial air daun tetap tinggi. Proses penggulungan daun ini berkaitan erat dengan peranan sel kipas. Pada saat kekurangan air, jumlah dan ukuran sel kipas meningkat, sehingga daun akan menggulung. Tingkat penggulungan daun dapat ditentukan secara visual berdasarkan sistem standar evaluasi untuk tanaman padi dengan memberi skor 1-9. Rendahnya tingkat penggulungan daun berkorelasi positif dengan meningkatnya potensial air daun. Kata kunci: menghindari kekeringan, penggulungan daun Abstract Leaf rolling is one mechanism of drought resistance, i.e. drought avoidance. This mechanism was resulted from decreasing evapotranspiration rate or increasing water absorption in the dry soil to maintain high leaf water potential. The process of leaf rolling in monocotyledon was closely related to the activity of bulliform cells. The number and size of bulliform cells were increased under water deficit, so that leaf rolling occurred. Leaf rolling score (1-9) could be visually determined based on the system of standard evaluation in rice. The low leaf rolling score was positively correlated with high leaf water potential. Keywords: drought avoidance, leaf rolling


Irriga ◽  
2010 ◽  
Vol 15 (3) ◽  
pp. 324-334
Author(s):  
Juliano Dalcin Martins ◽  
Reimar Carlesso ◽  
Alberto Eduardo Knies ◽  
Zanandra Boff de Oliveira ◽  
Tiago Broetto ◽  
...  

O potencial hídrico foliar pode ser considerado como um parâmetro de indicação da condição hídrica das culturas. Este trabalho teve como objetivo estudar o potencial hídrico foliar das plantas de milho sobre déficit hídrico no estágio inicial de desenvolvimento reprodutivo. O experimento foi conduzido no interior de uma cobertura móvel “Rainout shelter”, utilizando o delineamento experimental inteiramente casualizado, com dois tratamentos e quinze repetições. Os tratamentos foram constituídos de dois manejos da água de irrigação: (i) irrigado (as plantas de milho receberam irrigação conforme suas necessidades durante todo o ciclo de desenvolvimento); (ii) déficit hídrico aplicado antes do pendoamento.   O déficit hídrico teve uma duração de aproximadamente 50 mm de ETo acumulada. A cobertura móvel foi acionada quando da ocorrência de chuvas, impedindo que esta ocorresse sobre a área experimental. Determinou-se o conteúdo de água disponível nas camadas de 0-10, 10-25, 25-55 e 55-85 cm de profundidade e variação diária do potencial hídrico das folhas de milho. Não foram observadas diferenças entre os tratamentos para o potencial de água na folha. O potencial hídrico foliar em plantas de milho não apresenta variação para déficit hídrico de 50 mm de evapotranspiração de referência acumulada.   UNITERMOS: déficit hídrico, potencial hídrico foliar, milho, irrigação.     MARTINS, J. D.; CARLESSO. R.; KNIES, A. E.; OLIVEIRA, Z. B.; BROETTO, T.; RODRIGUES, G. J. LEAF WATER POTENTIAL IN MAIZE EXPOSED TO WATER DEFICIT 2 ABSTRACT   The leaf water potential can be considered as a parameter for indicating the crops water condition. This work aimed to study the maize leaf water potential on water deficit in the reproductive developmentinitial stage. The experiment was conducted within a mobile coverage "rainout shelter" using a completely randomized design with two treatments and fifteen repetitions. The treatments consisted of two water irrigation management: (i) irrigated (maize was irrigated as needed throughout the development cycle), (ii) water stress applied before tasseling. The drought lasted approximately 50 mm of accumulated reference evapotranspiration (ETo). The mobile coverage was triggered when rainfall occurred, preventing water from falling into the experimental area. Available water was determined  in layers of 0-10, 10-25, 25-55 and 55-85 cm depth and daily variation of water potential in maize leaves were also  evaluated. There were no differences between treatments for leaf water potential. The maize leaf water potential presented no change to water deficit equivalent to 50 mm of accumulated ETo.  KEYWORDS: water deficit, leaf water potential, maize, irrigation.


1976 ◽  
Vol 3 (3) ◽  
pp. 401 ◽  
Author(s):  
MM Ludlow ◽  
TT Ng

The responses of carbon dioxide exchange and leaf elongation of potted P. maximum var. trichoglume plants to water deficits were investigated in controlled environments and outdoors during drying cycles down to -92 bars leaf water potential, The sensitivities of net photosynthesis and leaf elongation to water deficits were similar. The leaf water potentials at which net photosynthesis and elongation ceased (c. -12 bars), and stomatal resistance increased substantially (- 6 bars), were relatively unaffected by nitrogen supply, environmental conditions during growth, and whether plants had previously experienced stress. However, these factors influenced the rate of net photosynthesis, at high leaf water potentials by affecting stomatal resistance and at moderate water potentials by affecting both stomatal and intracellular resistances. Stomata1 resistance was more sensitive than intracellular resistance to water deficits. Dark respiration rate decreased with leaf water potential, and was higher in plants receiving additional nitrogen. At moderate leaf water potentials (-7 to -9 bars), net photosynthesis of this C4 grass exhibited light saturation and rates similar to C3 plants. We suggest that the difference in behaviour of controlled-environment-grown and field-grown plants to water deficits observed with some species is unlikely to be due to differences in the aerial environment, but may result from differences in the rate at which stress develops. The ecological significance and evolution of the C4 syndrome are discussed briefly.


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