Increasing leaf export and grain import capacities in maize plants under water stress

2006 ◽  
Vol 33 (3) ◽  
pp. 209 ◽  
Author(s):  
Jacques Trouverie ◽  
Jean-Louis Prioul
Keyword(s):  
Water Stress ◽  
Water Deprivation ◽  
Time Course ◽  
Short Pulse ◽  
Invertase Activity ◽  
Mild Stress ◽  
Leaf Stage ◽  
Export Rate ◽  
Carbohydrate Concentration ◽  
Maize Plants

The export rate and the carbohydrate concentration were measured in maize plants submitted to water deprivation either at the fourth leaf stage or at pollination. Export rate was evaluated by a short pulse of labelling with 14CO2 followed by a 10-h chase. In stressed plants, 14C fixation was strongly reduced. When radioactivity was expressed relative to the initial value, the time course of label export from the labelled zone showed a faster decline in stressed plants than in well-watered plants. This was observed both under mild stress (fourth leaf stage) and severe stress (pollination stage). Another consequence of drought stress was an increase in fourth leaf vacuolar invertase activity and an increase in hexoses, which accumulated to the same content as sucrose. This occurred without a significant decrease in starch. At pollination stage, despite a large decrease in absolute quantity of 14C entering kernels, the proportion of leaf 14C export recovered in the kernel was not modified after a 4-d water deprivation, i.e. at day 0 after pollination (0 DAP), and was multiplied by a factor of 2–3 at 12 DAP. The major conclusion arising from these data appears to be an improvement of both leaf export and kernel import efficiency under water stress.

Deletion analysis of genes regulating cold- and PEG-induced carbohydrate accumulation in hydroponically raised wheat seedlings

2005 ◽  
Vol 53 (4) ◽  
pp. 359-370 ◽  
Author(s):  
G. Galiba ◽  
I. Kerepesi ◽  
J. W. Snape ◽  
A. Vágújfalvi
Keyword(s):  
Water Stress ◽  
Cold Hardiness ◽  
Water Deprivation ◽  
Time Course ◽  
Cold Treatment ◽  
Sugar Accumulation ◽  
Carbohydrate Accumulation ◽  
Wheat Seedlings ◽  
Time Course Experiment ◽  
Vernalization Genes

The mobilization of carbohydrates, especially sucrose, is considered very important during both the cold acclimation process and water stress, while sugars also promote floral transition and cold hardiness. Chinese Spring (CS) 5AL and 5DL deletion lines were studied for the physical assignment of the gene(s) regulating stress-induced sugar accumulation. To separate the effect of cold from that of water deprivation, the seedlings were raised in hydroponics, and apart from the cold, the effect of PEG-induced water stress was also evaluated in a time course experiment. The genes affecting stress-induced carbohydrate accumulation were assigned to the same chromosomal bins, which contain the vernalization genes Vrn-A1and Vrn-D1, on the long arms of chromosomes 5A and 5D, respectively. Sugar accumulation was found to be controlled by Vrngenes in an epistatic manner at least at the beginning of the cold treatment. In the case of cold treatment, Vrn-A1proved to be more effective than Vrn-D1, while in the case of osmotic stress the gene assigned to the long arm of chromosome 5D seemed to be more effective at regulating sugar accumulation than its counterpart on 5A.

Visual assessment of total plant relative water content, with the aid of photographic standards, as a guide to scheduling irrigation

1974 ◽  
Vol 14 (66) ◽  
pp. 76
Author(s):  
GJ Luke
Keyword(s):  
Water Stress ◽  
Water Status ◽  
Visual Assessment ◽  
Whole Plant ◽  
Accurate Indication ◽  
Relative Water ◽  
Total Plant ◽  
Scheduling Irrigation ◽  
Maize Plants ◽  
Water Contents

The relative water contents (RWC) of the top and bottom leaves of maize plants were measured. The RWC of the top leaf was higher than that of the bottom leaf when the plant was under water stress. Photographic standards based on the RWC of the whole plant were developed and tested against plants in the field. The results showed that the standards give an accurate indication of the plant's water status. Standards based on the upper leaf only would result in irrigations too infrequent to prevent severe restrictions to photosynthesis.

Influence of Moisture Deficits on the Reproductive Ability of Downy Brome (Bromus tectorum)

Weed Science ◽  
1989 ◽  
Vol 37 (4) ◽  
pp. 525-530 ◽  
Author(s):  
Jesse M. Richardson ◽  
David R. Gealy ◽  
Larry A. Morrow
Keyword(s):  
Water Stress ◽  
Seed Production ◽  
Irrigation System ◽  
Sprinkler Irrigation ◽  
Mild Stress ◽  
Downy Brome ◽  
Water Deficits ◽  
Reproductive Ability ◽  
Seed Fill ◽  
Hydroponic Study

Downy brome seed production was measured in the field following the establishment of different moisture levels using a line source sprinkler irrigation system. Results indicated that seed production was strongly affected by different moisture levels, with a curvilinear decrease in seed number from higher to lower moisture. In a hydroponic study with water deficits induced by PEG-8000, no seeds were produced when plants were severely stressed (-1.1 MPa) for a 7-day period during culm elongation or anthesis. Number of seeds/panicle was reduced under severe water stress during seed fill, under moderate stress (-0.5 MPa) during anthesis or seed fill, and under mild stress (-0.1 MPa) during anthesis. Water stress also reduced apparent photosynthesis and increased diffusive resistance of flag leaves, particularly under severe stress. In general, water deficits did not affect seed weights or germination percentages in either study.

scholarly journals Effects of Severe Water Stress on Maize Growth Processes in the Field

2019 ◽  
Vol 11 (18) ◽  
pp. 5086 ◽  
Author(s):  
Libing Song ◽  
Jiming Jin ◽  
Jianqiang He
Keyword(s):  
Water Stress ◽  
Chlorophyll Content ◽  
Field Experiments ◽  
Seedling Stage ◽  
Growth And Yield ◽  
Summer Maize ◽  
Photosynthetic Membrane ◽  
Area Index ◽  
Severe Water Stress ◽  
Maize Plants

In this study, we investigated the effects of water stress on the growth and yield of summer maize (Zea mays L.) over four phenological stages: Seedling, jointing, heading, and grain-filling. Water stress treatments were applied during each of these four stages in a water-controlled field in the Guanzhong Plain, China between 2013 and 2016. We found that severe water stress during the seedling stage had a greater effect on the growth and development of maize than stress applied during the other three stages. Water stress led to lower leaf area index (LAI) and biomass owing to reduced intercepted photosynthetically active radiation (IPAR) and radiation-use efficiency (RUE). These effects extended to the reproductive stage and eventually reduced the unit kernel weight and yield. In addition, the chlorophyll content in the leaf remained lower, even though irrigation was applied partially or fully after the seedling stage. Severe and prolonged water stress in maize plants during the seedling stage may damage the structure of the photosynthetic membrane, resulting in lower chlorophyll content, and therefore RUE, than those in the plants that did not experience water stress at the seedling stage. Maize plants with such damage did not show a meaningful recovery even when irrigation levels during the rest of the growth period were the same as those applied to the plants not subjected to water stress. The results of our field experiments suggest that an unrecoverable yield loss could occur if summer maize were exposed to severe and extended water stress events during the seedling stage.

SENSITIVITY OF CROP PLANTS TO WATER STRESS AT SPECIFIC DEVELOPMENTAL STAGES: REEVALUATION OF EXPERIMENTAL FINDINGS

1995 ◽  
Vol 43 (2) ◽  
pp. 99-111 ◽  
Author(s):  
Zvi Plaut
Keyword(s):  
Water Stress ◽  
Irrigation Water ◽  
Field Experiments ◽  
Developmental Stages ◽  
Growth Period ◽  
Soluble Solids ◽  
Growth Stages ◽  
Mild Stress ◽  
Uniform Reduction ◽  
Different Growth Stages

It has been suggested that in many crops differences in sensitivity to water stress occur at different growth stages. Since identical amounts of water may be applied, irrespective of whether a crop is exposed to relatively severe and short periods of stress or to extended periods of mild stress, the responses to such differing conditions should be compared. Unfortunately, such a comparison has not been conducted in most studies on sensitivity to water stress at different growth stages. In the present study, based on three field experiments conducted for different purposes, such a comparison was made for three crops: corn, sunflower, and tomato. In corn, distinct responses of ear and kernel yields to the timing of water stress were found. Withdrawal of irrigation water during flowering and cob formation resulted in greater yield losses than during other stages, indicating that this is a critical growth stage. However, slight and uniform reduction of water during the entire growth period resulted in significantly less damage to kernel or ear production, although the total amount of water applied was similar to that under staged withdrawal. In sunflowers, the withdrawal of irrigation water even at noncritical growth stages caused a more marked reduction in grain yield than did a uniform reduction throughout the entire season. In tomatoes, on the other hand, the withdrawal of irrigation water during specific growth stages caused minimal damage to fruit and total soluble solids yield as compared with fully irrigated control; reduction of irrigation water throughout the season brought about a significant decrease in yield. The difference between these crops is interpreted on the basis of the determinance of their floral meristems.

scholarly journals Modification of Petunia seedling Carbohydrate Partitioning by Irradiance

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1073d-1073
Author(s):  
David F. Grarper ◽  
Will Healy
Keyword(s):  
Leaf Area ◽  
Oxygen Evolution ◽  
Petunia Hybrida ◽  
Soluble Sugars ◽  
Dry Weight ◽  
Invertase Activity ◽  
Photon Flux ◽  
Total Carbohydrate ◽  
Leaf Stage ◽  
Area Basis

Petunia × hybrida Villm. `Red Flash' plants were irradiated for either 10 or 20 mol day1 photosynthetic photon flux (PPF) in growth chambers using one of the following treatments: 175 μmol m-2 s-1 for 16 h, 350 μmol m-2 s-1 for 8 or 16 h or 350 μmol m-2 s-1 for 8 h plus 8 h incandescent day extension (5 μmol m-2 s-1 PPF). These four treatments were designed to examine the effects of increased peak and total daily integrated PPF as well as increased photosynthetic (Pn) period and photoperiod resulting from supplemental irradiance treatment of seedlings. Previous seedling petunia research indicated a greater response to supplemental lighting during expansion of the second true leaf. Therefore, seedlings were sampled for analysis at the two leaf stage and also later at the four leaf stage to examine effects at a later stage of growth.Increasing total integrated PPF increased total carbohydrate production, seedling dry weight, rate of seedling growth, and acid invertase activity once the seedlings reached the two leaf stage. Increasing total PPF resulted in greater partitioning into ethanol soluble sugars rather than starch at the two leaf stage. Increasing the photoperiod only, with an incandescent day extension treatment, reduced total carbohydrate production at the two leaf stage.Maximal oxygen evolution was observed when seedlings received 350 μmolm-2s-1 for 8 h when expressed on a leaf area or dry weight basis. The use of an 8 h day extension treatment to extend the photoperiod from 8 to 16 h resulted in the lowest rates of oxygen evolution on a leaf area basis.

Comparison of the responses of two Indian mustard (Brassica juncea L.) genotypes to post-flowering soil water deficit with the response of canola (B. napus L.) cv. Monty

2009 ◽  
Vol 60 (3) ◽  
pp. 251 ◽  
Author(s):  
C. P. Gunasekera ◽  
R. J. French ◽  
L. D. Martin ◽  
K. H. M. Siddique
Keyword(s):  
Water Stress ◽  
Water Use ◽  
Seed Yield ◽  
Harvest Index ◽  
Dry Matter ◽  
Dry Matter Production ◽  
Mild Stress ◽  
Matter Production ◽  
Oil Concentration ◽  
Total Oil

The responses to water stress during the post-flowering period of two mustard breeding lines (887.1.6.1 and Muscon) and a commercial canola cv. Monty were tested in the field at Merredin in the low-rainfall Mediterranean-type environment of Western Australia. Three water-stress treatments were imposed using supplemental irrigation and a rain-exclusion shelter. Increasing water stress in the post-flowering period significantly reduced dry matter production and seed yields. Harvest index was slightly increased by mild stress, but reduced back to control levels by severe stress. Pods/plant, seeds/pod, and 1000-seed weight were all reduced by water stress. Dry matter production was higher in mustard than in canola, due to its greater water use and radiation interception. Water-use efficiency (WUE) for dry matter production and radiation-use efficiency (RUE) were higher in mustard than in canola. WUE for dry matter production and RUE were insensitive to the levels of water stress in mustard in this experiment, but declined significantly in canola. The greater water use in mustard and insensitivity of WUE for dry matter production and RUE to water stress were attributed to significantly higher levels of osmotic adjustment in mustard, although osmotic adjustment was also observed in canola. Despite this, canola seed yield was not significantly lower than the seed yield of the better mustard genotype, although stress caused a significantly greater percentage yield reduction in canola. This is because canola had a higher harvest index, which also meant it had higher WUE than mustard for grain production under mild stress. Mustard’s poorer harvest index was due to more of the dry matter being invested in stem and, in the case of cv. Muscon, to a short reproductive duration and a low proportion of pod weight allocated to seed. Canola had significantly higher seed oil concentration than mustard, which meant that it produced higher total oil yield despite sometimes producing lower seed yield. However, its oil concentration was reduced more by stress than mustard’s, so under the most severe stress conditions, both mustard genotypes produced higher total oil yield. Mustard has potential as an oil-producing crop in the low-rainfall Mediterranean-type environments of Western Australia, but improved genotypes, greater harvest index, and greater seed yield are required.

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