Photosynthesis in Wheat at the Grain Filling Stage Is Altered by Larval Wheat Stem Sawfly (Hymenoptera: Cephidae) Injury and Reduced Water Availability

2007 ◽  
Vol 42 (2) ◽  
pp. 228-238 ◽  
Author(s):  
Tulio B. Macedo ◽  
David K. Weaver ◽  
Robert K. D. Peterson

The impact of larval feeding by wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), and reduced water availability on the photosynthesis and primary metabolism of wheat, Triticum aestivum (L.), was evaluated at the grain-filling developmental stage. Photosynthetic parameters measured included photosynthesis (Ps), stomatal conductance (gs), and transpiration (E) in the flag leaves. The parameters were measured at 4 wks after the treatments were imposed. Additional concomitant chlorophyll a fluorescence measurements were taken using both dark- and light-adapted tests. Photosynthesis was significantly affected by C. cinctus injury and suboptimal water availability. However, no significant interaction was observed between the two treatment factors. Plants under a reduced or suboptimal watering regime had Ps rates that were 43.7% lower than plants that were watered daily. We also observed a 12% higher Ps rate in uninfested plants compared to plants infested by C. cinctus. Several chlorophyll a fluorescence parameters also were affected by C. cinctus. Specifically, reductions in the photochemical efficiency of photosystem II (PSII) of C. cinctus infested plants were observed for plants under reduced water availability. This study demonstrates that wheat plants at the grain filling stage have reduced photosynthetic capacity when watered less frequently or when subjected to C. cinctus larval feeding injury. Less frequent watering and larval feeding injury did not have significant impacts on yield in this greenhouse study.

2014 ◽  
Vol 40 (2) ◽  
pp. 173-178
Author(s):  
Nargis Jahan ◽  
AMM Golam Adam

An investigation on the effect of Naphthalene acetic acid (NAA) on the changes of biochemical components of two varieties of rice (Oryza sativa L.), BRR1 dhan 29 and BRRI dhan 50 was carried out. Two concentrations of NAA, 100 and 200 ppm were used as foliar spray. In BRRI dhan 29, significant increases in chlorophyll a and chlorophyll b contents of leaf were observed due to both the treatments at the flowering stage, whereas, carotenoids at the grain filling stage only. But in BRRI dhan 50, the total leaf pigments decreased at the flowering and grain filling stage, but was significant in case of chlorophyll a at the flowering stage. Significant increases in protein content of leaf were recorded at the tillering and flowering stage of BRRI dhan 29 following 100 ppm NAA treatment. In BRRI dhan 50, the only significant increase was recorded at grain filling stage due to 200 ppm NAA treatment. In both the varieties carbohydrates, protein, fat, and energy content of grain increased due to both the treatments and the maximum increase in all the cases was recorded due to 100 ppm NAA treatment. Ash and moisture content of grain reduced following both the treatments in both the varieties, the maximum reduction was due to 100 ppm NAA treatment Asiat. Soc. Bangladesh, Sci. 40(2): 173-178, December 2014


2012 ◽  
Vol 460 ◽  
pp. 286-289 ◽  
Author(s):  
Zhen Jiang Xu ◽  
Li Zhong Xiao ◽  
Hong Liu ◽  
Yong Hao Ren ◽  
Zhi Lin Li

Based on the experiment of two inbred aromatic rice varieties and one hybrid aromatic rice line treated under four different temperatures( daymean temperature 21°C, 23°C, 26°C and 30°C respectively) during grain filling stage in phytotrons, the shape and arrangement of endosperm starch granules in rice grain transection were observed by scanning electron microscope and the related characteristics of rice grain qualities of chalky percent and chalkiness were analyzed at the same time. The results showed that under the lower temperature( daymean temperature21°C and 23°C), many large compound starch granules with clear angulars packed together regularly without significant natural gaps bewteen starch granules in the tansectional endosperm. However, with the increase of temperature, starch granules in the transectional endosperm were changed from regularly shaped and closely and orderly arranged to various shaped and chaoticly arranged with obvious natural gaps between starch granules, which was closely consistent with the poorer appearance quality under the higher temperature, which indicated that the endosperm structure is closely related with appearance quality of aromatic rice.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7738
Author(s):  
Zhaoan Sun ◽  
Shuxia Wu ◽  
Biao Zhu ◽  
Yiwen Zhang ◽  
Roland Bol ◽  
...  

Information on the homogeneity and distribution of 13carbon (13C) and nitrogen (15N) labeling in winter wheat (Triticum aestivum L.) is limited. We conducted a dual labeling experiment to evaluate the variability of 13C and 15N enrichment in aboveground parts of labeled winter wheat plants. Labeling with 13C and 15N was performed on non-nitrogen fertilized (−N) and nitrogen fertilized (+N, 250 kg N ha−1) plants at the elongation and grain filling stages. Aboveground parts of wheat were destructively sampled at 28 days after labeling. As winter wheat growth progressed, δ13C values of wheat ears increased significantly, whereas those of leaves and stems decreased significantly. At the elongation stage, N addition tended to reduce the aboveground δ13C values through dilution of C uptake. At the two stages, upper (newly developed) leaves were more highly enriched with 13C compared with that of lower (aged) leaves. Variability between individual wheat plants and among pots at the grain filling stage was smaller than that at the elongation stage, especially for the −N treatment. Compared with those of 13C labeling, differences in 15N excess between aboveground components (leaves and stems) under 15N labeling conditions were much smaller. We conclude that non-N fertilization and labeling at the grain filling stage may produce more uniformly 13C-labeled wheat materials, whereas the materials were more highly 13C-enriched at the elongation stage, although the δ13C values were more variable. The 15N-enriched straw tissues via urea fertilization were more uniformly labeled at the grain filling stage compared with that at the elongation stage.


2019 ◽  
Vol 35 (6) ◽  
Author(s):  
Safdar Hussain ◽  
Abdul Rehman ◽  
Muhammad Akram ◽  
Javaid Iqbal ◽  
Tahira Batool Qaisrani ◽  
...  

Empowerment of wheat genotypes by application of growth regulators, compatible solutes and plant extracts under water restriction is an important strategy for getting sustainable yield. Field trail was performed at the research area of the Faculty of Agricultural Sciences, Ghazi University, Dera Ghazi Khan, Pakistan. Three wheat cultivars Aas-2011, Faisalabad- 2008 and Triple dwarf-1 were subjected to drought stress (skipping the irrigation at grain filling stage). The wheat genotypes were subjected to treatments viz., T1 i.e. All normal irrigation without application of abscisic acid (ABA), salicylic acid (SA), moringa (MLE) and mulberry leaf water extract (MBLE), T2­ i.e. skipping the irrigation at grain filling stage and application of 2µM ABA, T3 i.e. skipping the irrigation at grain filling stage and application of 10 m mol SA, T4 i.e. skipping the irrigation at grain filling stage and application of 15% MLE and T5 i.e. skipping the irrigation at grain filling stage and application of 10% MBLE. The experiment was laid out in Randomized Complete Block Design with factorial arrangement and repeated three times. From this study it is concluded that Aas-2011 shown best result under drought condition by applying growth regulators and plant water extracts. rs and plant water extracts.


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