Reduced Application of Nitrogen Fertilizer Affects the Carbon Metabolism of Leaves and Maintains the Number of Flowers in Coreopsis tinctoria

This study examined the effects of nitrogen (N) fertilizer reduction on the carbon (C) metabolism and yield of Coreopsis tinctoria. A two-year (2020–2021) hydroponic experiment was conducted in accordance with a randomized complete group design with five N levels [0.875 mM Ca(NO₃)₂ (N1), 1.750 mM Ca(NO₃)₂ (N2), 3.500 mM Ca(NO₃)₂ (N3), 7.000 mM Ca(NO₃)₂ (N4), and 14.000 mM Ca(NO₃)₂ (N5)] and three replications. The results showed that low N significantly affected the functional leaf weight, C metabolism, and flower bud (or flower) numbers of C. tinctoria at harvest. Lower-N levels, especially those of the N2 treatment, significantly increased Rubisco, sucrose synthase (SS), sucrose phosphate synthase (SPS), soluble acid invertase (SAI), glucose 6-phosphate dehydrogenase (G6PDH), and 6-phosphogluconate dehydrogenase (6PGDH) activity and maintained the flower number of C. tinctoria. In addition, the balance of carbohydrates (sucrose, starch, glucose, and fructose) and ATP contents was more efficiently maintained under relatively low-N levels. These findings might suggest that reduced application of N fertilizer affects the C metabolism of leaves and maintains the number of flowers in Coreopsis tinctoria. Applying relatively low-N fertilizer levels is also a promising cultivation strategy for C. tinctoria.

     

Biochemical and Physiological Responses of Cucumis sativus Cultivars to Different Combinations of Low-Temperature and High Humidity

Low-temperature and high humidity are typical environmental factors in the plastic tunnel and solar greenhouse during the cold season that restricts plant growth and development. Herein, we investigated the impact of different combinations of low-temperature and high humidity (day/night: T1 15/10 °C?+?95%, T2 12/8 °C?+?95%, and T3 9/5 °C?+?95%) along with a control (CK 25/18 °C?+?80%) on cucumber cultivars viz: Zhongnong37 (ZN37: resistant) and Shuyanbailv (SYB: sensitive). The low-temperature and high humidity stresses increased electrolyte leakage (EL), malondialdehyde (MDA), hydrogen peroxide (H₂O₂) and intercellular concentration of carbon dioxide (Ci), and reduced morphological indices, relative water content (RWC), net photosynthesis rate (Pn), stomatal conductance (Gs), transpiration rate (E) and leaf pigments in both cultivars as compared to control (CK). Superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), and glutathione reductase (GR) were decreased in cv. SYB under stress conditions as compared to cv. ZN37. Low-temperature and high humidity treatments showed an increase in proline and soluble protein content in cv. ZN37 as compared to cv. SYB. Abscisic acid (ABA) and jasmonic acid (JA) were augmented while indole-3-acetic acid (IAA), zeatin (ZT), zeatin riboside (ZR), and gibberellic acid (GA) were decreased in both cultivars. Under T3 (9/5 °C?+?95%), Pn, protoporphyrin, and ZT were extremely decreased by 71.3%, 74.3%, and 82.4%, respectively, in cv. SYB compared to control. Moreover, principal component analysis (PCA) based on physiochemical traits confirmed that cv. ZN37 had the strongest correlation with antioxidant enzymes, proline, and soluble protein content than cv. SYB under low-temperature and high humidity treatments. Our results suggest that a stress-tolerant cultivar mitigates stress damage in cucumber transplants by regulating photosynthetic efficiency, antioxidant capacity and hormonal profile when compared to a stress-sensitive cultivar.

     

Comprehensive Evaluation and Screening for 1,2,4-Trichlorobenzene Tolerance in Rice Cultivars at Different Growth Stages

Journal of Plant Growth Regulation - 1,2,4-trichlorobenzene (1,2,4-TCB) pollution in fields has become a potential threat to rice growth, yet little is known about the different response of many...     

The Effect of High-Temperature Stress on the Physiological Indexes,Chloroplast Ultrastructure,and Photosystems of two Herbaceous Peony Cultivars

In this study, two herbaceous peony cultivars with different heat tolerances (‘Fenyunu’ FYN low sensitivity and ‘Qiaoling’ QL high sensitivity) were used as research materials. An integrated view of the factors underlying the decrease in photosynthetic rate under high-temperature (HT) stress was provided by analyzing the biochemical parameters, chloroplast ultrastructure, gas-exchange parameters, chlorophyll fluorescence, and modulated 820 nm reflection of herbaceous peony leaves. The results showed that hydrogen peroxide, superoxide anion, malondialdehyde, and electrical conductivity increased significantly, while the photosynthetic pigments content and photosynthetic capacity decreased significantly in QL than in FYN under HT. The contents of soluble sugars and proline increased greatly in FYN than in QL, while the activity of SOD decreased markedly in QL than in FYN after HT. Compared with FYN, the ultrastructure of QL was more seriously disrupted under HT. Chlorophyll fluorescence analysis showed that HT changed the shapes of OJIP curve, resulting in the increase of K phase and J phase. The PSII acceptor side was more damaged than the donor side, and the electron transfer was seriously blocked. The energy flow in the process of light energy absorption, capture, and electron transfer were significantly changed after HT stress. Meanwhile, PSI was also significantly inhibited, and the coordination of both photosystems decreased. The variation of these parameters in FYN was less than that in QL. These results suggested that FYN featured a more heat-tolerance ability as evidenced by the good performances on the antioxidant system, osmoregulatory capacity, and the thermostability of membranes and photosystems.

     

Fulvic Acid,Brassinolide, and Uniconazole Mediated Regulation of Morphological and Physiological Traits in Maize Seedlings Under Water Stress

Water stress is one of the most important factors limiting sustainable crop production. Therefore, the effects of the plant growth regulators (PGRs) fulvic acid (FA), brassinolide (BR), and uniconazole (Uni) on seedling growth and physiology of two maize (Zea mays L.) varieties were evaluated under???0.7 MPa water stress induced by polyethylene glycol-6000. Under drought stress, the PGRs promoted seedling growth, altered the root-to-shoot ratio, and significantly increased root biomass, length, surface area, diameter, and volume. In addition, depending on the PGR, net photosynthesis rate, SPAD value (indicating chlorophyll content), and water use efficiency increased significantly, under drought stress, whereas transpiration rate decreased. The PGRs also significantly increased antioxidant enzyme activities and significantly decreased malondialdehyde accumulation in leaves and roots under drought stress. Zhengdan958 showed greater variation in physiological responses and stronger drought resistance than Xundan20. In alleviating drought stress in maize seedlings, FA had the greatest effects on shoot growth and leaf physiology; Uni exerted its effects by regulating root structure, and BR effects were intermediate. Under drought stress, the three PGRs increased maize seedling growth, which reduced drought stress-induced damage and improved plant ability to resist the adversity. Based on a comprehensive analysis of physiological indices of drought resistance, Uni is recommended as the best PGR to improve maize seedlings resistance to drought.

     

PDGF-AA activates AKT and ERK signaling for testicular interstitial Leydig cell growth via primary cilia

Testes control the development of male reproductive system. The testicular interstitial Leydig cells (Leydig cells) synthesize testosterone for promoting spermatogenesis and secondary sexual characteristics. Type A platelet-derived growth factor (PDGF-AA) is one of the most important growth factors in regulating Leydig cell growth and function. Knockout of PDGF-AA or its congenital receptor PDGFR-α leads to poor testicular development caused by reducing Leydig cell numbers, supporting PDGF-AA/PDGFR-α signaling regulates Leydig cell development. Primary cilium is a cellular antenna that functions as an integrative platform to transduce extracellular signaling for proper development and differentiation. Several receptors including PDGFR-α are observed on primary cilia for initiating signaling cascades in distinct cell types. Here we showed that PDGF-AA/PDGFR-α signaling promoted Leydig cells growth, migration, and invasion via primary cilia. Upon PDGF-AA treatment, AKT and ERK signaling were activated to regulate these cellular events. Interestingly, active AKT and ERK were detected around the base of primary cilia. Depletion of ciliary genes (IFT88 and CEP164) alleviated PDGF-AA-activated AKT and ERK, thus reducing Leydig cell growth, migration, and invasion. Thus, our study not only reveals the function of PDGF-AA/PDGFR-α signaling in maintaining testicular physiology but also uncovers the role of primary cilium and downstream signaling in regulating Leydig cell development.     

Phylogeography of the temperate grassland plant Tephroseris kirilowii (Asteraceae) inferred from multiplexed inter-simple sequence repeat genotyping by sequencing (MIG-seq) data

Journal of Plant Research - A group of temperate grassland plant species termed the “Mansen elements” occurs in Japan and is widely distributed in the grasslands of continental East...     

海水酸化及升温对刺参生长及能量收支的影响

以东亚浅海生态系统中的关键种——刺参(Apostichopus japonicus)为实验对象,研究了CO₂驱动的海水酸化及升温对其生长及能量收支的影响。实验设置对照组(大连近海水温, pCO₂ 400μatm)、升温组(大连近海水温+3℃, pCO₂ 400μatm)、酸化组(大连近海水温, pCO₂ 1100μatm)和酸化升温组(大连近海水温+3℃,pCO₂ 1100μatm)。结果表明:与对照组相比,温度升高3℃对刺参的生长无显著影响;酸化组刺参的特定生长率最低,较对照组降低0.19%/d,个体体重的变异系数最大;酸化升温组刺参的终末体重和特定生长率与对照组相较无显著差异,但其摄食率和排粪率均显著高于对照组。升温组和酸化组的刺参能量的分配模式与对照组相比未发生明显改变,但酸化升温组刺参的能量分配模式发生显著变化,其粪便能所占摄食能的比例显著升高。研究表明,海水酸化抑制了刺参的生长但未改变其能量的分配,生长的降低主要取决于摄食减少;而海水酸化与温度升高的共同作用可能会通过...     

三角帆蚌Hc-GSK3β基因鉴定及内壳色性状相关SNP筛选

为了探究三角帆蚌(Hyriopsis cumingii)糖原合成激酶-3β(GSK3β)基因对壳色的影响,研究采用RACE技术获得Hc-GSK3β基因cDNA全长1867 bp,其中包含1261 bp的ORF区编码420个氨基酸, ORF中含有一个S＿TKc结构域,该结构域序列高度保守。组织差异表达分析发现Hc-GSK3β基因在紫色蚌鳃、斧足、内脏团和边缘膜组织中表达量高于白色蚌的表达量(P<0.05),且在斧足和边缘膜表达差异水平达到极显著(P<0.01),而在紫色蚌闭壳肌组织中表达量显著低于白色蚌(P<0.05)。原位杂交(ISH)实验结果显示在三角帆蚌外套膜的外褶、中褶、內褶、背膜区和腹膜区均有阳性信号产生,且在外褶的信号表达较强烈。该基因经重测序比较,共鉴定出6个SNP位点,其中在C+185A位点的CA基因型在紫色蚌的分布频率显著高于白色三角帆蚌(P<0.05);在紫色蚌中, T+341G位点TT基因型三角帆蚌内壳颜色参数b值显著低于TG基因型(P<0.05)。研究表明, Hc-GSK3β基因参与了三角帆蚌壳色形成,筛选的SNP标记可用于三角帆蚌壳...