Nitric oxide signal is required for glutathione-induced enhancement of photosynthesis in salt-stressed Solanum lycopersicum L

Reduced glutathione (γ-glutamyl-cysteinyl-glycine, GSH), the primary non-protein sulfhydryl group in organisms, plays a pivotal role in the plant salt stress response. This study aimed to explore the impact of GSH on the photosynthetic apparatus, and carbon assimilation in tomato plants under salt stress, and then investigate the role of nitric oxide (NO) in this process. The investigation involved foliar application of 5 mM GSH, 0.1% (w/v) hemoglobin (Hb, a nitric oxide scavenger), and GSH+Hb on the endogenous NO levels, rapid chlorophyll fluorescence, enzyme activities, and gene expression related to the Calvin cycle in tomato seedlings (Solanum lycopersicum L. cv. ‘Zhongshu No. 4’) subjected short-term salt stress (100 mM NaCl) for 24, 48 and 72 hours. GSH treatment notably boosted nitrate reductase (NR) and NO synthase (NOS) activities, elevating endogenous NO signaling in salt-stressed tomato seedling leaves. It also mitigated chlorophyll fluorescence (OJIP) curve distortion and damage to the oxygen-evolving complex (OEC) induced by salt stress. Furthermore, GSH improved photosystem II (PSII) electron transfer efficiency, reduced QA- accumulation, and countered salt stress effects on photosystem I (PSI) redox properties, enhancing the light energy absorption index (PIabs). Additionally, GSH enhanced key enzyme activities in the Calvin cycle and upregulated their genes. Exogenous GSH optimized PSII energy utilization via endogenous NO, safeguarded the photosynthetic reaction center, improved photochemical and energy efficiency, and boosted carbon assimilation, ultimately enhancing net photosynthetic efficiency (Pn) in salt-stressed tomato seedling leaves. Conversely, Hb hindered Pn reduction and NO signaling under salt stress and weakened the positive effects of GSH on NO levels, photosynthetic apparatus, and carbon assimilation in tomato plants. Thus, the positive regulation of photosynthesis in tomato seedlings under salt stress by GSH requires the involvement of NO

Effect of Different Arbuscular Mycorrhizal Fungi on Growth and Physiology of Maize at Ambient and Low Temperature Regimes

The effect of four different arbuscular mycorrhizal fungi (AMF) on the growth and lipid peroxidation, soluble sugar, proline contents, and antioxidant enzymes activities of Zea mays L. was studied in pot culture subjected to two temperature regimes. Maize plants were grown in pots filled with a mixture of sandy and black soil for 5 weeks, and then half of the plants were exposed to low temperature for 1 week while the rest of the plants were grown under ambient temperature and severed as control. Different AMF resulted in different root colonization and low temperature significantly decreased AM colonization. Low temperature remarkably decreased plant height and total dry weight but increased root dry weight and root-shoot ratio. The AM plants had higher proline content compared with the non-AM plants. The maize plants inoculated with Glomus etunicatum and G. intraradices had higher malondialdehyde and soluble sugar contents under low temperature condition. The activities of catalase (CAT) and peroxidase of AM inoculated maize were higher than those of non-AM ones. Low temperature noticeably decreased the activities of CAT. The results suggest that low temperature adversely affects maize physiology and AM symbiosis can improve maize seedlings tolerance to low temperature stress

Tool Wear Prediction Based on Adaptive Feature and Temporal Attention with Long Short-Term Memory Model

Effective monitoring of tool wear status can improve productivity and reduce losses. In previous studies, extensive feature selection was required when using the traditional machine learning method. The gating mechanism in the traditional long short-term memory (LSTM) model may incur information loss and a weaker representation of global sequential dependencies in handling long sequences. This paper aims to enhance the performance of the LSTM model in tool wear prediction by combining feature and temporal attention. Firstly, the original vibration signal is divided into sub-sequences and related features extracted. Secondly, the ability to capture global sequential dependencies using the LSTM model is improved by feature and temporal attention. Finally, a fully connected layer is used to predict tool wear values. Compared to traditional LSTM, the proposed method performs best in three evaluation metrics, RMSE, MAE, and the coefficient of determination

Wide–Narrow Row Planting Pattern Increases Root Lodging Resistance by Adjusting Root Architecture and Root Physiological Activity in Maize (Zea mays L.) in Northeast China

Root lodging (RL) in maize can reduce yield and grain quality. A wide–narrow row planting pattern can increase maize yield in the growing regions of northeastern China, but whether it can improve RL resistance is not clear. Therefore, in this study, the root architecture distribution, root physiological activity, and root lodging rate under planting pattern 1 (uniform ridge of 65 cm, east–west ridge direction) and pattern 2 (wide–narrow rows, 40 double narrow rows and 90 wide rows, north–south ridge direction) were studied. The results showed that the RL rate under pattern 2 was significantly lower than that under pattern 1. The number and diameter of nodal roots on the upper node, the root failure moment, and the root bleeding sap intensity at the 3 weeks after VT under pattern 2 were significantly higher than those under pattern 1. Root length density in the 0–40 cm soil layer tended to be inter-row distributed. Therefore, the RL resistance of maize under pattern 2 was increased through an adjustment in the root architecture distribution and root physiological activity in northeastern China