Journal of Plant Research最新文献

Climate change imposes negative impacts on forest ecosystems through both abiotic stressors, such as drought, and biotic stressors, such as insect-induced defoliation. Chinese pine (Pinus tabulaeformis), a primary afforestation species in the northwest region of China, has recently faced increasing threats from drought and defoliation, leading to widespread mortality. This study investigates the combined effects of drought and defoliation on the growth and non-structural carbohydrate (NSC) dynamics of Chinese pine seedlings. A greenhouse-based manipulative experiment lasting 80 days was conducted, incorporating three watering treatments (100% field water-holding capacity, 30-40% field water-holding capacity, and no watering) and two defoliation treatments (defoliated and non-defoliated). Under moderate drought, seedlings exhibited increased concentrations of soluble sugars and starch in leaves and stems, demonstrating an active resistance to drought stress. However, under severe drought, NSC concentrations significantly decreased in all organs. Defoliation exacerbated the negative effects of drought, particularly impairing the NSC reserves in roots, thereby weakening the resilience of seedlings. The combination between drought and defoliation significantly altered the allocation patterns of soluble sugars and starch among roots, stems, and leaves in Chinese pine, highlighting the critical role of NSC in plant responses to environmental stressors. This study emphasizes the need to consider both drought and defoliation challenges simultaneously in ecological restoration practices to ensure the resilience of forest ecosystems.

Dehydration-responsive element binding (DREB) transcription factors (TFs) play an indispensable role in abiotic stress tolerance, including heat stress via abscisic acid (ABA) dependent and independent pathways. Among them, the DREB (A-6) subgroup remains least characterized, and the role of StDREB30 (A-6) under heat stress, particularly in association with ABA signaling, is not previously explored. This study aimed to characterize StDREB (A-6) group by molecular modelling and explore the role of StDREB30 in thermotolerance and its association with exogenous ABA. Molecular modelling was performed to predict 3D structures using SWISS-MODEL. STRING database was employed for protein-protein interactions (PPI), and molecular docking analysis was performed using the HDOCK server. Further, the role of StDREB30 (A-6) was assessed under heat (42 °C), ABA (50 µM), and combined (heat + ABA) treatments in potato. Overexpression of StDREB30 enhanced the tolerance in transgenic (T) potato under combined treatment of heat and ABA as compared to wild type (WT) counterparts. StDREB30 overexpressing plants showed significant upregulation of the StDREB30 gene, improved phenotypic traits and physiological features under heat and combined heat + ABA treatment. Transgenic lines maintained higher relative water content (i.e., 70% in T vs. 59% in WT), low malondialdehyde (3.1 nmol/g FW in T vs. 3.9 nmol/g FW in WT) and high anthocyanin content. It also improved photosynthetic parameters, including the maximum quantum yield of photosystem II (0.7 in T vs. 0.6 in WT), coefficient of photochemical quenching (0.6 in T vs. 0.49 in WT), and chlorophyll meter (SPAD) values (45 in T vs. 41 in WT). Moreover, RT-PCR analysis confirmed strong up-regulation of StDREB30 (i.e., 5.8, 6.1, and 7.2-fold in leaves, shoots and roots, respectively) under combined heat + ABA treatment compared to non-transgenic counterparts. The transgenic plants showed higher antioxidant activities, decreased reactive oxygen species, and cell death. Additionally, the combined (heat + ABA) treatment enhanced tuberization in transgenic plants. It is proposed that ABA primarily serves as a stress signal modulator without significantly influencing the physiological, biochemical and expression patterns under non-stressed conditions but significantly alleviates the effects of heat stress in combined treatment.

Tempo-spatial intracellular Ca²⁺ changes/oscillations mainly in cytoplasm and nucleoplasm are the primary mechanisms for the encoding and transmission of upstream stimulating signals to corresponding downstream responses, and the cytosolic Ca²⁺ signals are involved in numerous biological processes. External Ca²⁺ influx mediated by Ca²⁺ channels in the plasma membrane (PM) and the Ca²⁺ release from intracellular Ca²⁺ stores, such as vacuoles and endoplasmic reticulum (ER), respectively contribute to the majority and minority of Ca²⁺ for the generation of cytosolic Ca²⁺ signals, and the dynamic changes of PM Ca²⁺ channel activity directly control the rhythms of external Ca²⁺ influx and the subsequent cytosolic Ca²⁺ oscillations. Thus, the PM Ca²⁺ channels are the core components for Ca²⁺ signal encoding, but remain to be addressed for decades. Stomatal guard cell is an ideal plant cell model for deciphering Ca²⁺ signaling in plants, and more and more studies revealed that cyclic nucleotide-gated channels (CNGCs) play essential roles in Ca²⁺ signal encoding in guard cells. This minireview briefly summarizes the main recent advances in this field, highlights the core roles of CNGCs and underlying mechanism in guard cells, and discusses the possible remaining scientific questions and perspectives.

Reproductive interference is a negative interspecific interaction that can drive mutually exclusive distributions of closely related species. While recent research indicates that reproductive interference in plants frequently occurs during pollen-pistil interactions, comprehensive descriptions of these interactions are scarce. Understanding the mechanisms underlying reproductive interference requires studies integrating empirical observations with interaction analyses. This study investigates pollen-pistil interactions between three Veronica species recently observed to exhibit asymmetric reproductive interference.Our experiments revealed similar pollen tube behavior in V. polita var. lilacina and V. cymbalaria pistils, irrespective of whether they were pollinated with conspecific or V. persica pollen. Conversely, in V. persica pistils, the number of pollen tubes significantly decreased following heterospecific pollination compared to conspecific pollination. Furthermore, half of the pollen grains on V. persica stigmas, presumably heterospecific pollen grains, occasionally appeared non-luminous under the fluorescence microscope after mixed pollination. Conspecific pollen tubes appeared to grow faster within V. persica pistils; however, statistical analysis did not support this trend.These results suggest that V. polita var. lilacina and V. cymbalaria pistils exhibit limited discrimination against V. persica pollen, resulting in ovule discounting by the heterospecific pollen. This mechanism explains the empirical observation that these species experience reduced seed set after mixed pollination, even when conspecific pollen is applied first. In contrast, V. persica pistils demonstrate a degree of discrimination between conspecific and heterospecific pollen, particularly when conspecific pollen arrives on the stigma prior to heterospecific pollen. This selectivity accounts for the empirical findings that V. persica exhibits reduced seed set only when surrounded by V. polita var lilacina or after mixed pollination with V. cymbalaria pollen preceding conspecific pollen.

Kalanchoe species, originally introduced worldwide as ornamentals, are now reported to be globally spreading in many regions, including China. It is hypothesized that the morphological plasticity and asexual plantlet production of these species contribute to their rapid invasive spread. To address this hypothesis, an experiment was conducted using four Kalanchoe species: Kalanchoe delagoensis Eckl. & Zeyh., Kalanchoe × houghtonii D. B. Ward, Kalanchoe laetivirens Desc. and Kalanchoe daigremontiana Raym.-Hamet & H. Perrier. The reproductive and vegetative traits of these four species were evaluated under contrasting light and water conditions. The plants subjected to high light tended to prioritize plantlet production, accompanied by a reduction in vegetative growth. Two distinct reproductive strategies were observed. K. delagoensis and K. × houghtonii significantly increased plantlet production under high light conditions. In contrast, K. daigremontiana and K. laetivirens enhanced the fresh weight of individual plantlets without altering the total number produced. These results demonstrate the high plasticity of vegetative and reproductive growth in response to light and water availability. The increased production of plantlets may contribute to the invasive spread of Kalanchoe species in open fields.