Reduced stomatal conductance and irradiance account for soybean [Glycine max (L.) Merrill] yield decline in maize-soybean intercrop

2020 ◽  
Vol 24 (1) ◽  
pp. 1977-1989
Author(s):  
L. H. Mwamlima ◽  
E. K. Cheruiyot ◽  
J. P. Ouma

In some rice dominated tropical regions, such as in Indonesia, soybeans are an increasingly important dry season crop which are often exposed to periods of drought stress. The morphological and physiological responses, which could lead to some tolerance to water stress, may vary between varieties. By better understanding the plant response to drought stress and finding if these responses vary between varieties better dry season production could be achieved. An experiment was conducted to compare the response of four varieties of soybean (glycine max (l.) Meer.) to five watering regimes, with the objective of determining the response of common soybean varieies across a wide range of water supply. Plant response to water supply was measured using gas exchange measurement with the rate of photo synthesis decreasing progressively from well watered to dry conditions across the four varieties. A correlation of stomatal conductance and transpiration rate has a close relationship with photosynthetic rate, where stomatal conductance of Burangrang variety has higher value than other varieties. Varieties Burangrang and Argomulyo stomatal conductances are higher value than those of Anjasmoro and Grobogan varieties. In a deficit of water condition, the Argomulyo varieties have a higher value of transpiration efficiency and significantly different than the other three varieties. The transpiration efficiency significantly declined for treatments watered once every two or three weeks. The transpiration efficiency values of Agromulyo and Burangrang varieties were significantly higher than another varieties.


1992 ◽  
Vol 72 (2) ◽  
pp. 383-390 ◽  
Author(s):  
A. Djekoun ◽  
C. Planchon

Yield limitation in soybean (Glycine max L. Merr.) can result from decreases in photosynthesis and N2 fixation during periods of water deficiency. In this study, the relationships among stomatal conductance, photosynthesis and N2 fixation were analyzed in connection with drought tolerance of genotypes. Plants were grown in pots and exposed to field conditions. Carbon dioxide exchange rate was measured by gas analysis and nodule activity by the acetylene reduction method. Leaf water status was determined with a pressure bomb, and nodule water potential and leaf osmotic potential were measured psychrometrically. The differing tolerances of the cultivars Kingsoy and Hodgson to leaf water deficit resulted in a more or less developed ability of the lower side of the leaf to maintain good stomatal conductance during water stress. Stomatal conductance affects photosynthetic rate directly and acetylene reduction activity indirectly. Early stomatal closure, by limiting H2O exchange, contributes to conservation of nitrogenase activity. On the contrary, maintenance of high conductance during a water stress decreases soil water availability and nodule water content, which in turn has a decisive and limiting effect on acetylene reduction activity. Thus, if tolerance at low leaf water potentials associated with osmotic adjustment is an important drought mechanism for maintaining photosynthetic processes under water-limited conditions, the result would be obtained at the expense of symbiotic N2 fixation.Key words: Glycine max L. Merr., nitrogenase activity, photosynthesis, drought stress, soybean


2015 ◽  
Vol 32 (2) ◽  
pp. 153-159 ◽  
Author(s):  
Anna Nowak ◽  
Jacek Wróbel

In a two-year pot experiment (2008–2009) conducted at the Vegetation Hall, West Pomeranian University of Technology in Szczecin, we investigated the influence of exogenous growth regulators, i.e. indole-3-butyric acid (IBA) and 6-benzylaminopurine (BAP) and their mixture, on the activity of gas exchange and selected physiological features of soybeans (<em>Glycine max</em> L. Merr.). The experimental factors included the following Polish soybean cultivars: ‘Aldana’, ‘Progres’ and ‘Jutro’. During plant growth, CO<span><sub>2</sub></span> assimilation (A), transpiration rate (E), stomatal conductance (g<span><sub>s</sub></span>), and substomatal CO<span><sub>2</sub></span> concentration (c<span><sub>i</sub></span>) were determined. Two soybean cultivars, i.e. ‘Jutro’ and ‘Progres’, showed a significant increase in the intensity of assimilation and transpiration after using all kinds of growth regulators as compared with the control plants. It was found that the ‘Jutro’ cultivar, after using a mixture of growth regulators (IBA + BAP), was characterized by the significantly highest CO<span><sub>2</sub></span> assimilation (A) and transpiration (E) as well as the highest stomatal conductance (g<span><sub>s</sub></span>). The ‘Aldana’ cultivar, on the other hand, responded by a significant reduction in the transpiration rate, stomatal conductance and subsomatal CO<span><sub>2</sub></span> concentration. The spraying of the plants with exogenous growth regulators had a significant influence on the increase in the number of stomata and stomatal pore length, mostly on the lower epidermis of the lamina. It was also found that plants from the ‘Jutro’ and ‘Aldana’ cultivars sprayed with IBA and IBA + BAP were characterized by the highest yield, as compared with the control plants. In the case of the ‘Jutro’ cultivar, after using the growth regulators, a positive correlation was observed between the assimilation and transpiration rates and the length of stomata, which in consequence produced increased yields.


Weed Science ◽  
1993 ◽  
Vol 41 (1) ◽  
pp. 23-27 ◽  
Author(s):  
Rex A. Wichert ◽  
Ronald E. Talbert

Field studies were conducted in 1987 and 1988 to evaluate the vegetative response of soybeans to early postemergence applications of lactofen and to measure crop recovery. Soybean injury 4 d after treatment (DAT) averaged 29 and 34% with 0.22 and 0.44 kg ai ha−1of lactofen, respectively. Severity of leaf injury depended on leaf size at the time of lactofen application. Leaf area of soybean trifoliates one through three were reduced 30 to 45% at 12 DAT but recovered by 26 DAT. Later emerging trifoliates were not affected. Fresh weights of lactofen-treated soybeans were less than those of untreated plants 4, 8, and 16 DAT, and dry weights were less at 16 and 26 DAT. Lactofen reduced stomatal conductance of expanded leaves but had no effect on unexpanded leaves. Soybean yields did not differ with lactofen treatment.


Author(s):  
R. W. Yaklich ◽  
E. L. Vigil ◽  
W. P. Wergin

The legume seed coat is the site of sucrose unloading and the metabolism of imported ureides and synthesis of amino acids for the developing embryo. The cell types directly responsible for these functions in the seed coat are not known. We recently described a convex layer of tissue on the inside surface of the soybean (Glycine max L. Merr.) seed coat that was termed “antipit” because it was in direct opposition to the concave pit on the abaxial surface of the cotyledon. Cone cells of the antipit contained numerous hypertrophied Golgi apparatus and laminated rough endoplasmic reticulum common to actively secreting cells. The initial report by Dzikowski (1936) described the morphology of the pit and antipit in G. max and found these structures in only 68 of the 169 seed accessions examined.


2017 ◽  
Vol 2 (02) ◽  
pp. 204-218
Author(s):  
Hendra Saputra ◽  
Intan Sari ◽  
Muhammad Arfah
Keyword(s):  

Penelitian tentang pengaruh pemberian Pupuk organik cair (POC) asal limbah tumbuhan terhadap serapan hara N dan P serta produksi tanaman kedelai (Glycine max (L) Merrill) di lahan gambut telah dilaksanakan di kampus II Unisi Fakultas Pertanian Jl. Lintas Propinsi Parit 01, Desa Pulau Palas, Kecamatan Tembilahan Hulu, Kabupaten Indragiri Hilir Propinsi Riau. Dimulai dari bulan Agustus sampai bulan Oktober 2013. Tujuan dari penelitian ini untuk mendapatkan POC asal limbah tumbuhan yang terbaik untuk serapan hara N dan P serta produksi tanaman kedelai di lahan gambut. Penelitian ini menggunakan rancangan acak kelompok (RAK) faktor tunggal dengan 7 perlakuan dan 4 ulangan, 2 tanaman dijadikan sampel. Perlakuan dosis POC limbah tanaman pisang dan POC limbah sayur kol yang diberikan yaitu 0 L/Ha, 200 L/Ha, 400 L/Ha dan 600 L/Ha. Parameter pengamatan yaitu : serapan hara N dan P pada fase awal generatif, tinggi tanaman, jumlah bintil akar, polong hampa, produksi perplot, berat 100 biji dan brangkasan kering. Data pengamatan dianalisis dengan sidik ragam (ANOVA) dan dilanjutkan dengan Uji Lanjut Tukey HSD pada taraf 5%. Berdasarkan penelitian yang telah dilaksanakan dapat disimpulkan bahwa pemberian POC asal limbah tumbuhan tidak berpengaruh nyata terhadap serapan hara N dan P, tinggi tanaman, jumlah bintil akar, polong hampa, brangkasan kering tetapi berpengaruh nyata terhadap produksi perplot dan berat 100 biji.


2018 ◽  
Vol 1 (2) ◽  
pp. 96
Author(s):  
Siti Wahyuni ◽  
Umi Trisnaningsih ◽  
Meilina Prasetyo
Keyword(s):  

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