干旱胁迫植物个体生理响应及其生态模型预测研究进展

全球气候突变导致干旱事件频发，进而易引发严重的植物衰退甚至死亡，聚焦植物尤其是树木死亡的生理学机制并期望基于此评估及预测气候变化导致植物死亡风险已成为热点话题。植物通过调整内在生理代谢过程，例如通过调节渗透物质的含量，来平衡渗透势、维持细胞膨压、调节植物激素的信号水平，诱导植物气孔开放程度降低，有利于植物保存水分、调控植物水通道蛋白的表达，进而保持体内水分稳定并对干旱胁迫做出快速响应。这些生理过程中的每一环调节都为了确保水分运输的效率和安全性，增加植物抗旱性以及生态系统稳定性。植物的抗旱性不仅体现在生理代谢方面的调节，还表现在植物水力特性与解剖结构间相辅相成。当植物改变水力特性的同时，其茎叶会在解剖结构上做出调整以满足植物在干旱环境下水分供需平衡，从而降低植物蒸腾水分散失、增强细胞储水并提高生存能力。植物应对水分胁迫的策略通常与水分消耗和碳获取之间的平衡有关，明晰植物水分消耗与光合碳获取间存在平衡关系的性状特征便于更好地理解植物的水分利用策略。然而，植物表现出的任意单一性状特征的强弱都无法代表整个植物适应逆境的优劣，未来只有通过将植物更多性状特征进行相互关联，以具有代表植物水力功能、结...     

鱼糜制品加工品质影响研究进展

综述了鱼糜制品加工品质的研究进展，为产业发展提供科学依据。     

Plant water-regulation strategies: Isohydric versus anisohydric behavior

Water is a vital resource for plant survival, growth and distribution, and it is of significance to explore mechanisms of plant water-relations regulation and responses to drought in ecophysiology and global change ecology. Plants adapt to different climates and soil water regimes and develop divergent water-regulation strategies involving a suite of related traits, of which two typical types are isohydric and anisohydric behaviors. It is critical to distinguish water-regulation strategies of plants and reveal the underlying mechanisms for plant breeding and vegetation restoration especially in xeric regions; and it is also important for developing more accurate vegetation dynamic models and predicting vegetation distribution under climate change scenarios. In this review, we first recalled the definitions of isohydric and anisohydric regulations and three quantitative classification methods that were established based on the relationships (1) between stomatal conductance and leaf water potential, (2) between stomatal conductance and vapor pressure deficit, (3) between predawn and midday leaf water potentials. We then compared the two water-regulation strategies in terms of hydraulics and carbon-economics traits. We synthesized the mechanisms of plant water-regulation and found that the interaction between hydraulic and chemical signals was the dominant factor controlling plant water-regulation behavior. Last, we proposed three promising aspects in this field: (1) to explore reliable and universal methods for classifying plant water-regulation strategies based on extensive investigation of the traits related with plant water-relations in various regions; (2) to explore relationships between plant water-regulation strategies and traits of hydraulics, morphology, structure, and function in order to provide reliable parameters for improving vegetation dynamic models; and (3) to deeply understand the processes of plant water-regulation at different spatial and temporal scales, and reveal mechanisms of plants’ responses and adaption to environmental stresses (especially drought).     

外源凹凸棒土添加对半干旱矿区复垦土壤水分涵养功能的影响

大规模的采矿作业已对我国半干旱区植被生态造成很大破坏,矿区植被亟待恢复,以解决半干旱矿区日益恶化的生态环境问题。如何改良土壤、有效储存和利用降水是半干旱矿区复垦土地植被恢复的首要问题。本研究针对半干旱矿区复垦土地水分涵养功能不足的问题,提出利用凹凸棒土和当地砂土组配作为新覆土材料,并研究了外源凹凸棒土添加对神木矿区复垦土壤入渗、排水和储水能力的影响。结果表明: 随着凹凸棒土含量的增加,土壤的累积入渗量减少4.8%～37.4%,入渗率减少6.4%～46.3%,湿润锋推进速度减小9.8%～116.9%,饱和导水率减小14.3%～59.5%,24 h和72 h排水量分别减少0.3%～4.3%和0.3%～2.5%,土壤最大储水量增加1.6%～22.4%。外源凹凸棒土的作用效果在添加量为150 t·hm^-2时基本已达到最大,结合经济成本的最佳用量在30～150 t·hm^-2。本研究结果系统揭示了凹凸棒土对半干旱矿区土壤减渗保水的作用机理,证明其可以作为半干旱矿区复垦土壤改良的有效材料,为半干旱矿区土地复垦和植被恢复提供参考。     

Mesophyll conductance and its limiting factors in plant leaves

Mesophyll conductance (g_m) represents the CO₂ diffusion facility from sub-stomatal internal cavities to carboxylation sites in chloroplasts, and the variation of g_m across genotypes as well as environmental conditions is expected to be related to the anatomical structures and biochemical properties of leaves. In recent years, the variation of g_m has attracted wide attention. The limiting factors in photosynthetic rate are no longer divided simply into stomatal limitation and non-stomatal limitation, but splitted in stomatal limitation, mesophyll limitation and carboxylation limitation. In this review, we summarize the potential influences of cell wall, cell membrane, cytoplasm, chloroplast envelope and stroma on g_m, and indicate that cell wall thickness and the surface area of chloroplast exposed to intercellular air space (S_c) are the most important factors influencing the g_m. We also analyze the probable effects of biochemical process related with aquaporins and carbonic anhydrase on g_m. Meanwhile, the regulation mechanisms of long- and short-term environment changes (including temperature, light intensity, drought, and nutrients) on g_m are also summarized. The relationship between g_m and hydraulic conductance (K_leaf) is debated. Finally, we discuss the scientific problems related with g_m.     

中国热带珊瑚岛优势木本植物抗风桐和草海桐的水分适应策略解析

植物水力性状能够反映植物对不同水分条件的适应能力，研究热带珊瑚岛特殊生境下优势植物的水力功能特征对深入理解热带珊瑚岛植物的水分适应策略，从而选择热带珊瑚岛植被构建和恢复的适生物种具有重要意义。该研究以中国热带珊瑚岛生境中2种优势适生木本植物：抗风桐(Pisonia grandis)和草海桐(Scaevola sericea)为研究对象，比较了其叶片和枝条的水力性状，并分析了其水分适应策略。结果表明, 抗风桐的叶片栓塞抗性、枝条边材比导水率和叶片膨压丧失点显著高于草海桐，而枝条栓塞抗性、叶片导水率、边材密度和叶面积边材面积比均显著低于草海桐。抗风桐的叶片具有比枝条更强的抗栓塞能力，对水分胁迫敏感，但同时选择以高效的枝干水分运输来满足叶片高蒸腾需求的充足供水。草海桐枝条与叶片则存在水力脆弱性分区，在面临水分胁迫时叶片充当“安全阀”以保证枝干木质部的水力安全。抗风桐与草海桐能够通过协调叶片与枝条水力性状采取不同的水分适应策略，从而更好地适应热带珊瑚岛的特殊生境。