Natural Variations and Dynamic Changes of Nitrogen Indices throughout Growing Seasons for Twenty Tea Plant (Camellia sinensis) Varieties

Abstract

Tea (Camellia sinensis (L.) O. Kuntze) leaves are harvested multiple times annually accompanied by a large amount of nitrogen (N) removed. Therefore, tea plantations are characterized by high requirements of N. This study aimed to assess the variations of N-level, apparent N remobilization efficiency (ANRE), and N utilization efficiency (NUtE) and their dynamic changes during growing seasons for twenty tea varieties. The N-level was highest in the one bud with two leaves as the youngest category, followed by mature leaves attached to green-red stems, and then by aging leaves attached to grey stems. The dynamic N-level presented different profiles of “S”-, “U”-, and “S-like”-shape in the three categories of leaves during the growing seasons. Here, specifically defined ANRE indicated N fluxes in a specific category of leaves, showing that sources and sinks alternate during the period of two consecutive rounds of growth. The dynamic of averaged NUtE followed an “S”-shape. The results revealed annual rhythms and physiological characters related with N indices, which were variety dependent and closely related with the amount of N requirements at proper time. An optimized NUtE is a complex character determined by the combination of tea plantation management and breeding practices to achieve sustainable development with economic benefit.

CsATG101 Delays Growth and Accelerates Senescence Response to Low Nitrogen Stress in Arabidopsis thaliana

“…This reduction is probably caused by the decline in L4, approaching senescence. However, an exception, TGY, showed instantly increased transcript level in L2 and it might be due to a huge N requirement in L1, suggesting L2 acting as the source leaf and L1 as the N sink leaf, as our previous study identified that the sources and sinks alternate in the developed leaves of tea plants ( Zhang et al, 2020 ).…”

“…Meanwhile, tea plant is a commercial crop with round-by-round fresh leaves harvested annually, and a batch of tender shoots developed under suitable climate, making multiple sinks competed for the nutrients from soil or the sources. However, for the planation without N supply in time, the N uptake from soil is limited due to the continuous consumption, thus the mature leaves became the main sources ( Zhang et al, 2020 ). In our study, we also illustrated that at reproductive stage, both the seed yield and stubble biomass, N concentration and accumulation were lower in transgenic plants, while a relative higher N accumulation was distributed into seeds of transgenic plants, in contrast to WT.…”

“…Nitrogen (N) is an essential nutrient in plants for the synthesis of amino acids, proteins, and many other N-containing currency forms during the whole life. The tea plant [ Camellia sinensis (L.) O. Kuntze] is a perennial evergreen beverage plant with tender leaves for harvest, and large quantities of N are required due to the roundly plucking and pruning ( Chen et al, 2012 ; Zhang et al, 2020 ). In tea plantations, to achieve a top-quality and considerable yield, the base fertilizer and topdressing are two essential batches of fertilizer.…”

“…Usually, the base fertilizer is applied following the cessation of growth of the aboveground tea plants, while the topdressing is a fast-released fertilizer applied seasonally. Thus, the optimum time for topdressing is of great importance for tea plants ( Watanabe, 1995 ), and it should match the seasonal growth rhythm ( Zhang et al, 2020 ). However, the fluctuating N availability in soil is not sufficient to meet the real-time requirement of the tea plants.…”

Improving Tea Quality by Balancing ROS and Antioxidant System through Appropriate Ammonium Nitrogen Application

“…Tea (Camellia sinensis L.) is one of the important economic crops for leaf use in the world [1][2][3][4]. Nitrogen is an essential nutrient for sustaining tea plant growth and development, and it is also a key constituent element of tea quality, along with amino acids, tea polyphenols and caffeine [5][6][7]. Ammonium nitrogen (NH 4 + -N) is the favorite nitrogen form of tea plant [8][9][10], and could promote the improvement of tea yield and quality.…”