Effects of Irrigation and Nitrogen Application Rates on Protein and Amino Acid Content of Sunflower Seed Kernels

Liang Feng,Weiping Li,Haibin Shi,Yunfeng Hao,Qingxiao Shi,Sha Zhao,Hanjiang Liu

doi:10.3390/w13010078

Abstract

Sunflower seeds are rich in oil and protein. In a two-year field experiment in Hetao district, Inner Mongolia, we evaluated the effects of irrigation and N fertilizer on protein and amino acid content of sunflower seeds (Kang Di T562 variety). Irrigation water and N fertilizer were applied at the bud to blossom stage and at three levels: water at 90, 45, and 0 mm; N fertilizer at 104, 52, and 0 kg hm−2. There were nine treatments with three replicates for a total of 27 plots arranged randomly in blocks. In combination with environmental conditions, water, nitrogen, and the interaction between the two had significant effects on total protein, total amino acids, total ammonia, and key amino acids: glutamic acid, arginine, aspartic acid, glycine, and valine. Application of N fertilizer at the bud stage promoted protein synthesis in seed kernels at the ripening stage. We found a significant positive correlation between N fertilizer and the five main amino acids. With increasing irrigation, total amino acid content and the content of each of the key amino acids individually first increased but then decreased. Overall, a water deficit improved protein content in seed kernels.

Highlights

Amino Acid Content of SunflowerSunflower is the third largest oil crop and the fourth largest vegetable oil crop in the world [1]
Zhang et al studied the effects of altitude, latitude, and temperature on the protein and amino acid contents of sunflower seed kernel, and the results showed that the contents of protein and amino acid in sunflower seed kernel were higher at low altitude and the temperature difference was small [18]
Water 2021, 13, 78 seed kernel parts, and under the premise of harvest, we explored the influence of water and nitrogen on the sunflower seed kernel protein and amino acids, revealing the response law of sunflower seed kernel protein content and amino acid composition to water and nitrogen, providing technical support for the quality development of the sunflower industry

Summary

Introduction

Amino Acid Content of SunflowerSunflower is the third largest oil crop and the fourth largest vegetable oil crop in the world [1]. Sunflower seed kernels are rich in oil [3], protein [4], and amino acids [5,6]. To produce crops with the maximum number of amino acids and high levels of protein, plants must receive nutrients, nitrogen [8]. The nitrogen use efficiency of plants depends on levels in the soil and on the rate of accumulation before flowering when it is redistributed to the fruit and seeds [9]. Water stress is the most important environmental variable affecting plant growth, development, and seed production. The protein content and amino acid composition of sunflower seed kernels are affected by nitrogen fertilizer and irrigation, and by genetic variation, soil fertility, sunshine, disease, and planting time [8]

Methods

Results

Conclusion