scholarly journals On the Relationship between the Growth of Roots and the Starch contents in the Leaf-Sheaths of Rice Plants

1957 ◽  
Vol 26 (1) ◽  
pp. 15-16 ◽  
Author(s):  
Yoshinori FUJII ◽  
Noriyuki TANAKA
Keyword(s):  
2019 ◽  
Vol 7 (2) ◽  
pp. 287
Author(s):  
I Made Prasetia Candra Andika ◽  
I Made Anom Sutrisna Wijaya ◽  
Ida Bagus Putu Gunadnya

Penyakit blas merupakan salah satu penyakit yang berbahaya bagi tanaman padi. Penyakit ini bisa menyerang di setiap fase pertumbuhan. Perhitungan intensitas serangan penyakit blas saat ini masih  dilakukan secara manual. Diperlukan pengembangan teknologi dalam pendugaan intensitas serangan penyakit blas melalui citra NDVI. Penelitian ini bertujuan untuk (1) untuk mendapatkan ketinggian foto udara NDVI terbaik, (2) untuk mendapatkan umur tanaman padi dengan intensitas serangan penyakit blas tertinggi, (3) untuk mendapatkan hubungan antara intensitas serangan penyakit blas dengan nilai NDVI tanaman padi. Penelitian ini menggunakan Drone DJI Phantom 4 dengan lensa NDVI. Pengolahan data menggunakan Web Drone Deploy dan software Arc Gis 10.3. Berdasarkan dari hasil analisis, detail terbaik dari pembesaran 200% mendapatkan akuisisi ketinggian dari citra NDVI adalah 20 meter dengan ukuran piksel 1,4732 cm/pixel. Pertumbuhan intensitas serangan penyakit blas tertinggi  terjadi pada umur 98 hari setelah tanam. Hubungan antara intensitas serangan penyakit blas dengan nilai NDVI memiliki koefisien determinasi sebesar 0,986. Persamaan regresi didapatkan dalam penelitian ini adalah y = -23345x3 + 21191x2- 6416,8x + 665,07 dengan akurasi sebesar sebesar 91,74%.   Blast is one of disease that is dangerous for rice plants. This disease can attack in every phase of growth. Calculation of the intensity of blast disease attacks is still done manually. Technology development is needed in estimating the intensity of blast disease attacks through NDVI imagery. This study purpose (1) to get the best NDVI aerial photo altitude, (2) to get the age of rice plants with the highest attack intensity of blast disease, (3) to get a relationship between the intensity of blast disease and the NDVI value of rice plants. This study use Drone DJI Phantom 4 with lens NDVI. Processing data using Web Drone Deploying and Arc Gis 10.3 software. Based on the analysis results, the best detail of 200% zooming results obtained altitude of the NDVI image acquisition that is 20 m with pixel density of 1,4732 cm/pixel. The highest intensity of blast disease attacks occurs at the age of 98 days after planting. The relationship between the intensity of blast disease and NDVI value has a determination coefficient of 0.986. The regression equation obtained in this study is y = -23345x3 + 21191x2- 6416,8x + 665,07 with an estimated accuracy of 91,74%.


1997 ◽  
Vol 24 (5) ◽  
pp. 563 ◽  
Author(s):  
Yoshito Watanabe ◽  
Yasunori Nakamura ◽  
Ryuichi Ishii

The starch stored temporarily in the leaf sheath of rice plants is translocated to the grain, contributing to the grain yield. In this paper, the relationship between starch accumulation and the activities of enzymes involved in the starch biosynthetic pathway in the leaf sheaths of rice plants was examined to elucidate the regulation mechanism of starch accumulation in the temporary sink organ. When the starch content was compared between different leaf sheath positions on the main stem, the 14th leaf sheath counted from the bottom, which elongated just before anthesis, showed about a four-fold higher value than the 10th leaf sheath. Among the enzymes involved in carbohydrate metabolism, the activity of starch branching enzyme (BE, EC2.4.1.18) was greatly higher in the 14th leaf sheath than in the 10th leaf sheath, while that of ADPglucose pyrophosphorylase (EC2.7.7.27) was similar between the two leaf sheaths. The starch content increased rapidly in the period around anthesis in the 12th and 14th leaf sheaths, but did not in the 10th and 11th leaf sheath. In the higher leaf sheath position, the activity of BE changed with noticeably similar trend to the starch content. Soluble starch synthase (SSS, EC2.4.1.21), granule-bound starch synthase (GBSS, EC2.4.1.21) and plastidial fructose- 1,6-bisphosphatase (FBPase, EC3.1.3.11) were also significantly correlated with the starch content. These results suggest that BE is involved in regulation of starch metabolism, possibly in collaboration with other enzymes such as SSS, GBSS and plastidial FBPase in temporary sink organs like the leaf sheath.


Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1075
Author(s):  
Ok Jin Hwang ◽  
Kyoungwhan Back

We investigated the relationship between the blue-light photoreceptor cryptochrome (CRY) and melatonin biosynthesis by generating RNA interference (RNAi) transgenic rice plants that suppress the cryptochrome 1b gene (CRY1b). The resulting CRY1b RNAi rice lines expressed less CRY1b mRNA, but not CRY1a or CRY2 mRNA, suggesting that the suppression is specific to CRY1b. The growth of CRY1b RNAi rice seedlings was enhanced under blue light compared to wild-type growth, providing phenotypic evidence for impaired CRY function. When these CRY1b RNAi rice plants were challenged with cadmium to induce melatonin, wild-type plants produced 100 ng/g fresh weight (FW) melatonin, whereas CRY1b RNAi lines produced 60 ng/g FW melatonin on average, indicating that melatonin biosynthesis requires the CRY photoreceptor. Due to possible feedback regulation, the expression of melatonin biosynthesis genes such as T5H, SNAT1, SNAT2, and COMT was elevated in the CRY1b RNAi lines compared to the wild-type plants. In addition, laminar angles decreased in the CRY1b RNAi lines via the suppression of brassinosteroid (BR) biosynthesis genes such as DWARF. The main cause of the BR decrease in the CRY1b RNAi lines seems to be the suppression of CRY rather than decreased melatonin because the melatonin decrease suppressed DWARF4 rather than DWARF.


2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Ping He ◽  
Cong Wang ◽  
Neng Zhang ◽  
Bin Liu ◽  
Yang Yang ◽  
...  

AbstractRice is a crucial food crop worldwide. The genetic diversity in rice germplasm indicates its promising potential utilization in disease and pest control. To explore the relationship between genetic diversity and disease resistance in rice plants, multi-genotype rice varieties developed from multi-parent advanced generation inter-cross (MAGIC) population lines were used here to analyze the correlation between disease occurrence and genetic diversity, as well as for field monitoring of their disease occurrences and yields. We found that genetic diversity and disease resistance of the multi-genotype varieties tested in this study were superior to those of their component lines and mono-genotype varieties, and the incidence of rice blast disease decreased as the genetic diversity of multi-genotype rice varieties increased. We further conducted field trials using these multi-genotype varieties for three years in different rice-planting areas. The results showed that multi-genotype varieties exhibited good disease resistance and high-yielding potential. Thus, proper use of multi-genotype varieties characterized by rich genetic diversity is a promising approach to improve disease resistance of rice plants in agricultural production systems and is of great significance for ensuring food security and achieving sustainable agricultural development.


1980 ◽  
Vol 49 (2) ◽  
pp. 317-322 ◽  
Author(s):  
Koou YAMAZAKI ◽  
Manabu KATANO ◽  
Shin-ichiro KAWATA

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