How Integrated Management Strategies Promote Protein Quality of Cotton Embryos: High Levels of Soil Available N, N Assimilation and Protein Accumulation Rate

Sustainable management practices for durum wheat production: Analyzing specific agronomic interventions on productivity, grain micronutrient content, and quality

As compared with single agronomic crop management practices during grain formation, knowledge about integrated agronomic management practices on grain mineral composition and grain technological properties in durum wheat is limited. This knowledge is important for determining management strategies aimed at increasing grain yield without affecting grain nutritional quality. Integrated agronomic practices such as foliar nutrient application × seeding rate × varieties combined with growing locations were investigated to evaluate the dynamics of yield and grain quality traits. Two durum wheat varieties, three-level of micronutrients (i.e. control, FeSO4, and ZnSO4), and four levels of seeding rate (i.e. 100, 125, 150, and 175 kg ha-1) were arranged in split-split plot design under two different growing locations (environments). The main plots were assigned to the varieties, subplots to micronutrients, and sub-sub plots to the seeding rate treatments. Zinc and iron were applied in a form of ZnSO4 and FeSO4 at the early flowering stage, both at a rate of 25 kg ha-1. Results showed a linear increment in biomass (21.5%) and grain yield (23.5%) under a high seeding rate, even though the 1000-grain weight, the number of grains spike-1, spike length, and the number of grains spike-1 were decreased. Higher varietal and environmental response of seeding rate was observed between varieties. The grain protein content, gluten, and zeleyn index decreased as the seeding rate increased. Grain micronutrient content was significantly influenced by seeding rate and varietal difference. The grain protein content was higher in a dryland environment than in a wet environment. A combined use of density-tolerant varieties, high seeding rate, and foliar-based iron application can improve the grain yield from 2.01 to 3.20 t ha-1 under a potential environment. Hence, all stakeholders should consider the genotype (G), environment (E), management (M), and their synergies, as far as grain yield and quality are considered simultaneously.

Phosphorus-induced greater enhancement in carbon supply and storage for oil synthesis during the crucial period made cottonseed kernel oil yield have a higher increment than protein

Cottonseed has a high utilization value due to its luxuriant oil and protein, but low phosphorus (P) in cropland reduces its yield and quality. A limited understanding of the physiological mechanism underlying these results restricted the exploration of P efficient management in cotton cultivation. A 3-year experiment was performed with Lu 54 (low-P sensitive) and Yuzaomian 9110 (low-P tolerant) under 0 (deficient-P), 100 (critical-P), and 200 (excessive-P) kg P₂O₅ ha^-1 in a field having 16.9 mg kg^-1 available P to explore the key pathway for P to regulate cottonseed oil and protein formation. P application markedly increased cottonseed oil and protein yields, with the enhanced acetyl-CoA and oxaloacetate contents during 20-26 days post anthesis being a vital reason. Notably, during the crucial period, decreased phosphoenolpyruvate carboxylase activity weakened the carbon allocation to protein, making malonyl-CoA content increase greater than free amino acid; Meanwhile, P application accelerated the carbon storage in oil but retarded that in protein. Consequently, cottonseed oil yield increased more than protein. Oil and protein synthesis in Lu 54 was more susceptible to P, resulting in greater increments in oil and protein yields than Yuzaomian 9110. Based on acetyl-CoA and oxaloacetate contents (the key substrates), the critical P content in the subtending leaf to cotton boll needed by oil and protein synthesis in Lu 54 (0.35%) was higher than Yuzaomian 9110 (0.31%). This study provided a new perception of the regulation of P on cottonseed oil and protein formation, contributing to the efficient P management in cotton cultivation.

Sodium lignosulfonate improves shoot growth of Oryza sativa via enhancement of photosynthetic activity and reduced accumulation of reactive oxygen species

Lignosulfonate (LS) is a by-product obtained during sulfite pulping process and is commonly used as a growth enhancer in plant growth. However, the underlying growth promoting mechanism of LS on shoot growth remains largely unknown. Hence, this study was undertaken to determine the potential application of eco-friendly ion-chelated LS complex [sodium LS (NaLS) and calcium LS (CaLS)] to enhance recalcitrant indica rice MR 219 shoot growth and to elucidate its underlying growth promoting mechanisms. In this study, the shoot apex of MR 219 rice was grown on Murashige and Skoog medium supplemented with different ion chelated LS complex (NaLS and CaLS) at 100, 200, 300 and 400 mg/L The NaLS was shown to be a better shoot growth enhancer as compared to CaLS, with optimum concentration of 300 mg/L. Subsequent comparative proteomic analysis revealed an increase of photosynthesis-related proteins [photosystem II (PSII) CP43 reaction center protein, photosystem I (PSI) iron-sulfur center, PSII CP47 reaction center protein, PSII protein D1], ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), carbohydrate metabolism-related proteins (glyceraldehyde-3-phosphate dehydrogenase 3, fructose-bisphosphate aldolase) and stress regulator proteins (peptide methionine sulfoxide reductase A4, delta-1-pyrroline-5-carboxylate synthase 1) abundance in NaLS-treated rice as compared to the control (MSO). Consistent with proteins detected, a significant increase in biochemical analyses involved in photosynthetic activities, carbohydrate metabolism and protein biosynthesis such as total chlorophyll, rubisco activity, total sugar and total protein contents were observed in NaLS-treated rice. This implies that NaLS plays a role in empowering photosynthesis activities that led to plant growth enhancement. In addition, the increased in abundance of stress regulator proteins were consistent with low levels of peroxidase activity, malondialdehyde content and phenylalanine ammonia lyase activity observed in NaLS-treated rice. These results suggest that NaLS plays a role in modulating cellular homeostasis to provide a conducive cellular environment for plant growth. Taken together, NaLS improved shoot growth of recalcitrant MR 219 rice by upregulation of photosynthetic activities and reduction of ROS accumulation leading to better plant growth.

Growth promoting effects of Pluronic F-68 on callus proliferation of recalcitrant rice cultivar

This study was undertaken to evaluate growth-promoting effects of Pluronic F-68 (PF-68) on recalcitrant MR 219 rice callus. Our study shows that calli grown on Murashige and Skoog medium supplemented with 0.04% PF-68 significantly increased callus proliferation by 58.80% (fresh weight) and 23.98% (dry weight) while root formation from callus was enhanced by 28.57%. Enhanced callus proliferation was supported by biochemical analysis, whereby highest amount of soluble sugar (1.77 mg/mL) and protein (0.17 mg/mL) contents were recorded in calli grown on 0.04% PF-68. Furthermore, enhanced expression of sucrose synthase (2.65-folds) and NADH-dependent glutamate synthase (1.86-folds) genes in calli grown on 0.04% PF-68 also correlates with enhanced callus proliferation. In contrast, high concentration of PF-68 (0.10%) recorded highest amount of phenolic (0.74 mg/mL), flavonoid (0.08 mg/mL), and hydrogen peroxide content (0.06 mg/mL) as compared to other treatment groups indicates activation of plant defence mechanism towards stress. Similarly, high expression of 4-coumarate:CoA ligase 3 (1.28-folds), chalcone-flavonone isomerase (1.65-folds) and ascorbate peroxidase (1.61-folds) genes were observed in calli grown on 0.10% PF-68 further supports increasing stress caused by the high concentration of PF-68. Taken together, our study revealed that optimum concentration of PF-68 could improve recalcitrant rice callus proliferation via enhanced sugar metabolism and amino acid biosynthesis which are crucial towards plant growth and development. However, at high concentration, PF-68 induces stress in plant which enhance the production of secondary metabolite to maintain cellular homeostasis.

A Comparative Study of Integrated Crop Management System vs. Conventional Crop Management System for Cotton Yield and Fiber Quality With Respect to Fruiting Position Under Different Soil Fertility Levels

In order to increase cotton productivity and optimize fiber quality on limited arable land, an integrated crop management system (ICMS), which combined with some optimal management practices, is projected to replace the conventional crop management system (CCMS) for cotton production in the Yangtze River valley. The seedcotton yield and fiber quality with respect to fruiting position under ICMS and CCMS were investigated in 2012 and 2013 in two fields differing in soil fertility. Reduced bolls on fruiting branches 1-10 (FB_1-10) and at fruiting position 1-2 (FP_1-2) on FB_11-15 could not be fully compensated by increased bolls on FB₁₆₊ under CCMS, resulting in more seedcotton yield under ICMS relative to that under CCMS. Fiber at majority fruiting positions under CCMS were longer and stronger than those under ICMS, but CCMS increased the contribution of bolls on FB₁₁₊ to the cotton yield, which overall resulted in no significant change in fiber length and strength by management system at field level. The number of bolls at FP_1-2 on FB_1-5 under CCMS while the number of bolls on FB_1-5 and at FP_1-2 on FB_1-5 were not significantly changed by soil fertility, resulting in diminished yield difference in soil fertility among ICMS relative to that of CCMS. The high soil fertility significantly increased seedcotton yield relative to low soil fertility, which was attributed to more number of bolls on FB₁₁₊ and higher seedcotton weight per boll at all fruiting positions. High soil fertility field not only recorded superior fiber quality on FB₁₁₊, but also increased the contribution of these bolls to the cotton yield relative to those in the low soil fertility field, resulting in no significant change in overall fiber quality among soil fertility. These findings demonstrate that by combining optimal management practices on infertile soils ICMS could minimize the yield differences due to soil fertility without sacrificing fiber quality.

Integrated Management Strategies Increase Cottonseed, Oil and Protein Production: The Key Role of Carbohydrate Metabolism

Cottonseed, oil, and protein, as the by-products of cotton production, have the potential to provide commodities to meet the increasing demand of renewable bio-fuels and ruminant feed. An increase in crop yield per unit area requires high-yielding cultivar management with an economic nitrogen (N) rate, an optimal N application schedule, high-yielding plant populations and strong seedlings. Whether the integration of these agronomic practices into a coherent management system can increase the productivity of cotton fiber, embryo oil and protein requires experimental elucidation. In this 2-year study, conventional management practices (CM) were used as a control, and two integrated management strategies (IMS1 and IMS2) were considered at two soil fertility levels (high soil fertility and low soil fertility) to analyze the metabolic and biochemical traits of cotton embryos. The results illustrate that the cottonseed, oil, and protein yields for IMS1 and IMS2 were significantly higher than those under CM at both soil fertility levels and the fiber yield increased as well. The IMS regulated the maternal photo thermal environment by delaying the flowering date, resulting in increases in the seed weight. In developing cotton embryos, the IMS increased the embryo weight accumulation rate and biomass partitioning into oil and protein, which were associated with high activities of H+-ATPase, H+-PPase, sucrose synthase (SuSy), and cell wall invertase (C-INV) and low activities of sucrose phosphate synthase (SPS) and vacuole invertase (V-INV). Increased hexoses (D-fructose, D-glucose) content contributed to the oil and protein contents. These results suggest that increased sucrose/H+ symport, sucrose hydrolysis, hexoses synthesis, and cumulative photo-thermal product (PTP), especially in the early stage of embryo growth, play a dominant role in the high productivity of cotton oil and protein.