Durum wheat ears perform better than the flag leaves under water stress: Gene expression and physiological evidence

Vicente, Rubén; Vergara-Díaz, Omar; Medina, Susan; Chairi, Fadia; Kefauver, Shawn C.; Bort, J.; Serret, María Dolores; Aparicio, Nieves; Araus, J. L.

doi:10.1016/j.envexpbot.2018.06.004

Cited by 68 publications

(99 citation statements)

References 69 publications

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“…ATPase) in the flag leaf but not in the ear, and that the upregulation of respiration‐related genes, such as phosphoenolpyruvate carboxylase (PEPCase), 2‐oxoglutarate dehydrogenase complex (OGDC), alternative oxidase (AOX) and pyruvate kinase, was associated with the increased refixed CO 2 in the ear organs. An observed upregulation of dehydrins (Abebe et al , ), increased transcript levels of antioxidant enzyme genes (Vicente et al , ), followed by high levels of antioxidant enzymes and low levels of ROS (Kong et al , ) confirmed the higher drought tolerance of the ear and its importance as a main contributor to grain weight and, more broadly, grain yield under disadvantageous environmental conditions.…”

Section: Importance Of Photosynthesis In Non‐foliar Cereal Organsmentioning

confidence: 92%

“…Numerous studies provide strong evidence that the ear possesses an elevated drought tolerance when compared with the flag leaf and highlight the ear as the main potential buffer for photoassimilate production under disadvantageous environments (Jia et al, 2015). Additionally, the ear shows a lower transpiration rate than the flag leaf and a higher intrinsic WUE, confirmed by less negative d 13 C values (Araus et al, 1993;Tambussi et al, 2007;Sanchez-Bragado et al, 2014;Vicente et al, 2018). Xeromorphic characteristics in glumes, lemmas and awns of durum wheat have been observed, such as sclerenchymatous tissue and thick walls (Tambussi et al, 2005).…”

Section: Photosynthetically Active Ear Componentsmentioning

confidence: 99%

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Photosynthesis in non‐foliar tissues: implications for yield

et al. 2020

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Summary Photosynthesis is currently a focus for crop improvement. The majority of this work has taken place and been assessed in leaves, and limited consideration has been given to the contribution that other green tissues make to whole‐plant carbon assimilation. The major focus of this review is to evaluate the impact of non‐foliar photosynthesis on carbon‐use efficiency and total assimilation. Here we appraise and summarize past and current literature on the substantial contribution of different photosynthetically active organs and tissues to productivity in a variety of different plant types, with an emphasis on fruit and cereal crops. Previous studies provide evidence that non‐leaf photosynthesis could be an unexploited potential target for crop improvement. We also briefly examine the role of stomata in non‐foliar tissues, gas exchange, maintenance of optimal temperatures and thus photosynthesis. In the final section, we discuss possible opportunities to manipulate these processes and provide evidence that Triticum aestivum (wheat) plants genetically manipulated to increase leaf photosynthesis also displayed higher rates of ear assimilation, which translated to increased grain yield. By understanding these processes, we can start to provide insights into manipulating non‐foliar photosynthesis and stomatal behaviour to identify novel targets for exploitation in continuing breeding programmes.

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Section: Importance Of Photosynthesis In Non‐foliar Cereal Organsmentioning

confidence: 92%

Section: Photosynthetically Active Ear Componentsmentioning

confidence: 99%

Photosynthesis in non‐foliar tissues: implications for yield

et al. 2020

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“…For that reason, thermal images have proven to be easier to process than RGB images, in part due to their lower resolution, without the lack of contrast and technical limitations of multisensory array multispectral imagers. In fact, the ears, and regardless of the water conditions, are usually several degrees warmer than the leaves [25], due to their constitutive lower stomatal conductance and thus transpiration rates compared with the leaves [39]. For this study, we measured the leaf and the ear temperature, with differences within images ranging 1.9-5.0 • C, 2.1-3.4 • C and 2.0-5.0 • C for Aranjuez, Sevilla and Valladolid, respectively.…”

Section: Discussionmentioning

confidence: 99%

“…Thermal information has been used mainly for monitoring crop water status [17][18][19][20][21][22] and irrigation management [23,24]. However, previous studies have shown that, regardless of the water conditions during the growing season, there are often significant constitutive differences between leaf and ear temperature on sunny days [25], with ear temperature being higher than leaf temperature. This suggests that thermal imagery may provide a useful approach for ear counting [26].…”

Section: Introductionmentioning

confidence: 99%

Automatic Wheat Ear Counting Using Thermal Imagery

et al. 2019

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Ear density is one of the most important agronomical yield components in wheat. Ear counting is time-consuming and tedious as it is most often conducted manually in field conditions. Moreover, different sampling techniques are often used resulting in a lack of standard protocol, which may eventually affect inter-comparability of results. Thermal sensors capture crop canopy features with more contrast than RGB sensors for image segmentation and classification tasks. An automatic thermal ear counting system is proposed to count the number of ears using zenithal/nadir thermal images acquired from a moderately high resolution handheld thermal camera. Three experimental sites under different growing conditions in Spain were used on a set of 24 varieties of durum wheat for this study. The automatic pipeline system developed uses contrast enhancement and filter techniques to segment image regions detected as ears. The approach is based on the temperature differential between the ears and the rest of the canopy, given that ears usually have higher temperatures due to their lower transpiration rates. Thermal images were acquired, together with RGB images and in situ (i.e., directly in the plot) visual ear counting from the same plot segment for validation purposes. The relationship between the thermal counting values and the in situ visual counting was fairly weak (R2 = 0.40), which highlights the difficulties in estimating ear density from one single image-perspective. However, the results show that the automatic thermal ear counting system performed quite well in counting the ears that do appear in the thermal images, exhibiting high correlations with the manual image-based counts from both thermal and RGB images in the sub-plot validation ring (R2 = 0.75–0.84). Automatic ear counting also exhibited high correlation with the manual counting from thermal images when considering the complete image (R2 = 0.80). The results also show a high correlation between the thermal and the RGB manual counting using the validation ring (R2 = 0.83). Methodological requirements and potential limitations of the technique are discussed.

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“…Chlorophyll fluorescence and chlorophyll degradation were also widely used as typical markers of developmental senescence progression and photosynthesis (Kong et al ., 2010, 2017; Lyu et al ., 2017; Kang et al ., 2018). Higher values of them were closely associated with the grain yield (Vicente et al ., 2018). The evidence from our physiological analysis and the ultrastructural observations of flag leaf mesophyll cells suggest that half-degraining may cause later but defoliation cause earlier leaf senescence.…”

Section: Discussionmentioning

confidence: 99%

Source-Sink Modifications Affect Leaf Senescence and Grain Mass in Wheat

Zhang

et al. 2019

Preprint

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1 A field experiment was performed in wheat to investigate the responses of flag leaf and grain to 2 sink/source manipulations. The results showed that half-degraining delayed but defoliation (only 3 flag leaf left) enhanced the leaf senescence. Sink/source manipulations influenced the content of 4 1 1 Chloroplast Structure 1 2 At 16 DAM, visual observation did not find difference in senescing flag leaf between three 1 3 Fv/Fm 0.0 0.2 0.4 0.6 0.8

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Durum wheat ears perform better than the flag leaves under water stress: Gene expression and physiological evidence

Cited by 68 publications

References 69 publications

Photosynthesis in non‐foliar tissues: implications for yield

Photosynthesis in non‐foliar tissues: implications for yield

Automatic Wheat Ear Counting Using Thermal Imagery

Source-Sink Modifications Affect Leaf Senescence and Grain Mass in Wheat

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