Functions of Nitrogen, Phosphorus and Potassium in Energy Status and Their Influences on Rice Growth and Development

doi:10.1016/j.rsci.2022.01.005

Abstract

Abstract:

Nitrogen (N), phosphorus (P) and potassium (K) are important essential nutrients for plant growth and development, but their functions in energy status remains unclear. Here, we grew Nipponbare rice seedlings in a growth chamber for 20 d at 30 ºC/24 ºC (day/night) under natural sunlight conditions with different nutrient regimes. The results showed that N had the strongest influence on the plant growth and development, followed by P and K. The highest nonstructural carbohydrate content, dry matter weight, net photosynthetic rate (Pn), ATP content, as well as NADH dehydrogenase, cytochrome oxidase and ATPase activities were found in the plants that received sufficient N, P and K. The lowest values of these parameters were detected in the N-deficient plants. Higher dry matter accumulation was observed in the K-deficient than in the P-deficient treatments, but there was no significant difference in the ratio of respiration rate to Pn between these two treatments, suggesting that differences in energy production efficiency may have accounted for this result. This hypothesis was confirmed by higher ATP contents and activities of NADH dehydrogenase, cytochrome oxidase and ATPase in the K-deficient plants than in the P-deficient plants. We therefore inferred different abilities in energy production efficiency among N, P and K in rice seedlings, which determined rice plant growth and development.

Key words: rice, nutrient element, photosynthesis, respiration, plant growth and development, energy production efficiency

Ma Jiaying, Chen Tingting, Lin Jie, Fu Weimeng, Feng Baohua, Li Guangyan, Li Hubo, Li Juncai, Wu Zhihai, Tao Longxing, Fu Guanfu. Functions of Nitrogen, Phosphorus and Potassium in Energy Status and Their Influences on Rice Growth and Development[J]. Rice Science, 2022, 29(2): 166-178.

Figures/Tables 8

Fig. 1. Effects of N, P and K on plant morphology of rice. A, Phenotype of rice plants at 20 d after nutritional treatments. Scale bar is 10 cm. B, Total chlorophyll content. C, Plant height. D, Tiller number per plant. E, Dry matter weight per plant. Eight treatments were used: no fertilization (H2O); standard N, P and K fertilization (NPK); P and K fertilization without N (-N); N and K fertilization without P (-P); N and P fertilization without K (-K); ½N with standard P and K fertilization (½N); ½P with standard N and K fertilization (½P); and ½K with standard N and P fertilization (½K). Data are Mean ± SD (n = 8). One-way analysis of variance was conducted to compare the difference with least signiﬁcant difference test at P ≤ 0.05. Different lowercase letters above the bars indicate signiﬁcant differences among treatment

Fig. 2. Effects of N, P and K on contents of carbohydrates in rice plant leaves. A, Soluble sugar content. B, Starch content. C, Nonstructural carbohydrate (NSC) content. Eight treatments were used: no fertilization (H2O); standard N, P and K fertilization (NPK); P and K fertilization without N (-N); N and K fertilization without P (-P); N and P fertilization without K (-K); ½N with standard P and K fertilization (½N); ½P with standard N and K fertilization (½P); and ½K with standard N and P fertilization (½K). Data are Mean ± SD (n = 3). One-way analysis of variance was conducted to compare the difference with least signiﬁcant difference test at P ≤ 0.05. Different lowercase letters above the bars indicate signiﬁcant differences among treatments.

Fig. 3. Effects of N, P and K on photosynthesis, respiration and photorespiration in rice plant leaves. A, Net photosynthetic rate (Pn). B, Respiration rate (Rd). C, Photorespiration rate (Pr). D, Ratio of Rd to Pn. E, Ratio of Pr to Pn. F, Ribulose 1,5-bisphosphate carboxylase activity. G, Ribulose 1,5-bisphosphate oxygenase activity. H, Ratio of oxygenase to carboxylase. Eight treatments were used: no fertilization (H2O); standard N, P and K fertilization (NPK); P and K fertilization without N (-N); N and K fertilization without P (-P); N and P fertilization without K (-K); ½N with standard P and K fertilization (½N); ½P with standard N and K fertilization (½P); and ½K with standard N and P fertilization (½K). Data are Mean ± SD (n = 3). One-way analysis of variance was conducted to compare the difference with least signiﬁcant difference test at P ≤ 0.05. Different lowercase letters above the bars indicate signiﬁcant differences among treatments.

Fig. 4. Effects of N, P and K on energy production efficiency in rice plant leaves. A, NADH dehydrogenase (Complex I) activity. B, Cytochrome oxidase (Complex IV) activity. C, ATPase (Complex V) activity. D, ATP content. Eight treatments were used: no fertilization (H2O); standard N, P and K fertilization (NPK); P and K fertilization without N (-N); N and K fertilization without P (-P); N and P fertilization without K (-K); ½N with standard P and K fertilization (½N); ½P with standard N and K fertilization (½P); and ½K with standard N and P fertilization (½K). Data are Mean ± SD (n = 3). One-way analysis of variance was conducted to compare the difference with least signiﬁcant difference test at P ≤ 0.05. Different lowercase letters above the bars indicate signiﬁcant differences among treatments.

Fig. 5. Effects of N, P and K on the antioxidant capacity, H2O2 and lipid peroxidation in leaves of rice plants. A, Superoxide dismutase (SOD) activity. B, Peroxidase (POD) activity. C, Catalase (CAT) activity. D, Ascorbate peroxidase (APX) activity. E, H2O2 content. F, Malondialdehyde (MDA) content. Eight treatments were used: no fertilization (H2O); standard N, P and K fertilization (NPK); P and K fertilization without N (-N); N and K fertilization without P (-P); N and P fertilization without K (-K); ½N with standard P and K fertilization (½N); ½P with standard N and K fertilization (½P); and ½K with standard N and P fertilization (½K). Data are Mean ± SD (n = 3). One-way analysis of variance was conducted to compare the difference with least signiﬁcant difference test at P ≤ 0.05. Different lowercase letters above the bars indicate signiﬁcant differences among treatments.

Fig. 6. Changes in contents of total N (A), available P (B) and available K (C) in rice plant leaves under different nutrient conditions. Eight treatments were used: no fertilization (H2O); standard N, P and K fertilization (NPK); P and K fertilization without N (-N); N and K fertilization without P (-P); N and P fertilization without K (-K); ½N with standard P and K fertilization (½N); ½P with standard N and K fertilization (½P); and ½K with standard N and P fertilization (½K). Data are Mean ± SD (n = 3). One-way analysis of variance was conducted to compare the difference with least signiﬁcant difference test at P ≤ 0.05. Different lowercase letters above the bars indicate signiﬁcant differences among treatments.

Table 1. Ratios among N, P and K contents in rice plants under different nutrient conditions.

Treatment	N	P	K
H₂O	10.0	3.1	9.4
NPK	10.0	2.0	5.9
-N	10.0	3.1	10.1
-P	10.0	2.1	7.6
-K	10.0	1.9	4.6
½N	10.0	2.2	7.5
½P	10.0	2.1	6.8
½K	10.0	1.9	6.1

Fig. 7. Model of NPK functioned in energy production efficiency in rice plants. When the plants was provided adequate NPK, the photosynthesis of leaves and the energy production efficiency such as the activities of NADH dehydrogenase, cytochrome oxidase and ATPase of leaves in the electron transport chain of oxidative phosphorylation in mitochondria were enhanced, which would produce more energy in plants, and thus significantly increased the accumulation of dry matter weight. In contrast, when the NPK was insufficient, the photosynthesis and energy production were inhibited, resulting in lower ATP production, which can reduce the dry matter accumulation.

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