Clonal differences in ecophysiological responses to imposed drought in selected Eucalyptus grandis × E. urophylla hybrids.

IF 3.5 2区农林科学 Q1 FORESTRY

Tree physiology Pub Date : 2025-01-25 DOI:10.1093/treephys/tpae160

Tiago Massi Ferraz, Sebastião de Oliveira Maia Júnior, Guilherme Augusto Rodrigues de Souza, Danilo Força Baroni, Weverton Pereira Rodrigues, Elias Fernandes de Sousa, Ricardo Penchel, Rodolfo Loos, Fábio Afonso Mazzei Moura de Assis Figueiredo, Miroslava Rakocevic, Eliemar Campostrini

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引用次数: 0

Abstract

Measuring ecophysiological responses of Eucalyptus clones grown under reduced water availability could assist in clonal selection for climate resilience. We hypothesized that clonal variation in chlorophyll a fluorescence was more readily detected than variations in leaf-level gas exchanges when 2-year-old Eucalyptus grandis W.Hill ex Maiden × Eucalyptus urophylla S.T. Blake hybrid clones (C1, C2, C3 and C4) grown under rainfed (RF) and water-restricted (WR) conditions were evaluated during dry and rainy seasons, in the morning and midday diurnal periods. The C2 clone was the most drought tolerant as it had a similar net CO2 assimilation rate (A) considering the RF and WR conditions at midday during the dry season, while C1, C3 and C4 CO2 assimilation rates (A) decreased by 29.1%, 28.3% and 13%, respectively. This response was associated with a reduction to a lesser extent in leaf water potential, stomatal conductance (gs) and transpiration rates (E) (ca 10%, 30% and 13% under WR, respectively), when compared with the other clones during the dry season at midday. The lower leaf to air vapor pressure deficit of C2 contributed to its greater water-use efficiency (WUE), resulting in greater total dry mass gain. C1, C3 and C4 were less drought tolerant, decreasing gs, E and especially A under WR, resulting in lower WUE and total dry mass gain. Chlorophyll a fluorescence indexes were better indicators of drought tolerance compared with gas exchange parameters in definition of drought tolerance of clonal Eucalyptus. Three drought-sensitive clones showed low photochemical efficiency under WR, with the electron transport rate being impaired between photosystems II and I, indicated by the greater changes in photosynthetic performance index (PIabs). Under WR conditions, Fv/Fm, Ψ0, ΦE0 and PIabs decreased in all clones while ΦD0 and DI0/CS0 increased, with C2 showing the most stable responses suggesting that the photochemical apparatus was the less damaged by drought. Thus, C2 was the best clone for regions with water scarcity.

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大桉与尾叶桉杂交种对干旱生态生理响应的无性系差异。

测定水分有效度降低条件下桉树无性系的生理生态响应，有助于气候适应力无性系的选择。我们假设，在旱季和雨季的早晨和中午，在雨养（RF）和限水（WR）条件下生长的2年生大叶子沙×尾叶叶子沙杂交无性系（C1、C2、C3和C4），叶绿素a荧光的克隆变化比叶片水平气体交换的变化更容易被检测到。C2无性系的耐旱性最好，考虑到旱季正午的RF和WR条件，C2无性系的CO2净同化率(a)相似，而C1、C3和C4无性系的CO2同化率(a)分别下降了29.1%、28.3%和13%。与其他无性系相比，在旱季中午，这种反应与叶片水势、气孔导度（gs）和蒸腾速率(E)的降低程度较低（WR下分别为10%、30%和13%）。C2叶片对空气蒸汽压差较低，水分利用效率较高，总干质量增加较大。C1、C3和C4的耐旱性较差，在WR下gs、E、尤其是A均降低，导致水分利用效率和总干质量增益降低。与气体交换参数相比，叶绿素a荧光指标是更好的耐旱性指标。3个干旱敏感无性系在WR条件下光化学效率较低，光系统II和光系统I之间的电子传递速率受损，光合性能指数（PIabs）变化较大。WR条件下，Fv/Fm、Ψ0、ΦE0和PIabs均降低，ΦD0和DI0/CS0升高，其中C2反应最稳定，说明光化学装置受干旱影响最小。因此，C2是缺水地区的最佳无性系。

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来源期刊

Tree physiology 农林科学-林学

CiteScore

7.10

自引率

7.50%

发文量

133

审稿时长

1 months

期刊介绍： Tree Physiology promotes research in a framework of hierarchically organized systems, measuring insight by the ability to link adjacent layers: thus, investigated tree physiology phenomenon should seek mechanistic explanation in finer-scale phenomena as well as seek significance in larger scale phenomena (Passioura 1979). A phenomenon not linked downscale is merely descriptive; an observation not linked upscale, might be trivial. Physiologists often refer qualitatively to processes at finer or coarser scale than the scale of their observation, and studies formally directed at three, or even two adjacent scales are rare. To emphasize the importance of relating mechanisms to coarser scale function, Tree Physiology will highlight papers doing so particularly well as feature papers.