Effects of Suboptimal Low Temperatures on Leaf Structure and Photosynthetic Fluorescence Characteristics of Strawberry During Reproductive Period

doi:10.13304/j.nykjdb.2024.0301

Abstract

Abstract:

In order to explore the adaptation mechanism of strawberries under suboptimal low temperature， 2 strawberry varieties of Ningyu and Jingzangxiang were taken as materials. The phenotype traits， photosynthetic parameters， rapid chlorophyll fluorescence parameters and leaf ultrastructure of strawberry leaves under different treatments during the reproductive period were determined. The results showed that， under suboptimal low temperature， there was no significant change on plant-type of Ningyu， while the plant-type of Jingzangxiang gradually opened from the intermediate type and the leaf color gradually changed to yellow green. With the prolongation of suboptimal low temperature， the leaf area， leaf thickness and leaf volume of Ningyu significantly decreased， the leaf tissue density significantly increased， the specific leaf area first increased and then decreased， and the leaf dry matter content firstly decreased and then increased. With the prolongation of suboptimal low temperature， the leaf area and volume of Jingzangxiang increased， while the leaf thickness decreased， the leaf tissue density and leaf dry matter content first decreased and then increased， the specific leaf area and density showed a trend of first increasing and then decreasing. With the prolongation of suboptimal low temperature， there was no significant change in chlorophyll content in leaves of Ningyu， however， the chlorophyll a content of Jingzangxiang increased significantly. The net photosynthetic rate， stomatal conductance and intercellular CO₂ concentration of Ningyu leaves all significantly increased after 7 d of stress， and decreased after 14 d of stress. Suboptimal low temperature led to a decrease in water use efficiency， although it increased after 14 d of stress， it was still lower than the control at the same period. For Jingzangxiang， the net photosynthetic rate of leaves significantly decreased after 14 d of stress， while the intercellular CO₂ concentration and stomatal conductance significantly increased after 7 d of stress and decreased after 14 d of stress， the transpiration rate under suboptimal low temperature treatment decreased after 14 d of stress， and the overall trend of water use efficiency was similar to that of Ningyu. Energy transfer of Ningyu leaves was hindered after 14 d of suboptimal low temperature treatment （ΔW_OK>0）， however， the Jingzangxiang had already been hindered after 7 d of stress. The suboptimal low temperature had a significant impact on the oxygen release complexes of Ningyu and Jingzangxiang， and both oxygen release complexes were inactivated （ΔW_OJ>0）. The leaf mesophyll cells of Ningyu and Jingzangxiang under control treatment were intact， and the chloroplast and other structures were intact and clear. Under suboptimal low temperature treatment， the mitochondria in the mesophyll cells of Ningyu were slightly swollen， and a few rough endoplasmic reticulum were slightly dilated. After 14 d of stress， the lamellae and stacking structure of chloroplasts became blurred. After 7 d of stress， Jingzangxiang showed slight cytoplasmic wall separation， chloroplast structure dissolution， unclear outer membrane boundary， and disordered arrangement of lamellar structure. After 14 d of stress， chloroplasts dissolved and denatured， and lamellar structure became blurred. In summary， the leaves of strawberry should adjust under suboptimal low temperature treatment， but long-term suboptimal low temperature could reduce the photosynthetic performance of the leaves and damage the leaf ultrastructure. The damage caused by suboptimal low temperature to the photosystemⅡ reaction center and chloroplasts of Jingzangxiang was greater than that of Ningyu. The plant status， photosynthetic performance and other indicators of Ningyu were relatively stable， and its ability to low temperature was stronger than Jingzangxiang.

Key words: strawberry, leaf structural traits, photosynthesis, suboptimal low temperature, leaf ultrastructure

摘要：

为探究草莓在亚适低温下的适应机制，以宁玉和京藏香2个草莓品种为材料，以常温处理为对照，研究亚适低温胁迫对生殖期草莓株型及叶片表型、光合参数、快速叶绿素荧光参数、叶片超微结构的影响。结果表明，在亚适低温胁迫下，宁玉株型无明显变化，京藏香的株型由中间型逐渐开张，叶片渐变为黄绿色。随着亚适低温时间的延长，宁玉的叶面积、叶厚度和叶体积均显著减小，叶组织密度显著增加，比叶面积先增加后降低，叶干物质含量先降低后增大；京藏香叶面积和叶体积增加，叶厚度减小，叶组织密度和叶干物质量先减小后增大，比叶面积和叶组织密度先增大后减小。随着亚适低温时间的延长，宁玉叶片的叶绿素含量无显著变化；但京藏香叶片中叶绿素a含量显著增加。宁玉叶片的净光合速率、气孔导度和胞间CO₂浓度均在胁迫7 d时显著升高，胁迫14 d时有所降低，亚适低温致使其水分利用效率降低，虽在14 d时有所增加，但仍低于同期对照；京藏香叶片的净光合速率在胁迫14 d时显著降低，胞间CO₂浓度、气孔导度在胁迫7 d时显著升高，胁迫14 d回降，蒸腾速率在胁迫14 d时降低，水分利用效率降低。宁玉叶片在胁迫14 d时能量传递受阻（ΔW_OK>0）；而京藏香在胁迫7 d时已受到阻碍。亚适低温胁迫对宁玉和京藏香放氧复合体的影响较大，放氧复合物均失活（ΔW_OJ>0）。宁玉与京藏香对照组叶片的叶肉细胞完好，叶绿体等结构完整清晰。在亚适低温胁迫下，宁玉叶肉细胞的线粒体轻度肿胀，少数粗面内质网轻度扩张，胁迫14 d时，叶绿体中片层及垛叠结构模糊；京藏香在胁迫7 d时已出现轻微质壁分离现象，叶绿体结构溶解，外膜界限不清，片层结构排列紊乱，胁迫14 d后，叶绿体溶解变性，片层结构模糊。综上可见，草莓处于亚适低温胁迫下叶片会相应调整，但长时间亚适低温会降低叶片光合性能、伤害叶超微结构。亚适低温胁迫对京藏香光系统Ⅱ反应中心及叶绿体造成的伤害较宁玉更大，宁玉的植株状态、光合性能等指标相对稳定，其耐低温能力强于京藏香。

关键词: 草莓, 叶结构型性状, 光合, 亚适低温, 叶超微结构

CLC Number:

S668.4

Fuxia YANG, Huan HE, Ling TANG, Kuanying LI, Fen LIU, Jianjun CHEN. Effects of Suboptimal Low Temperatures on Leaf Structure and Photosynthetic Fluorescence Characteristics of Strawberry During Reproductive Period[J]. Journal of Agricultural Science and Technology, 2025, 27(10): 51-62.

杨馥霞, 贺欢, 汤玲, 李宽莹, 刘芬, 陈建军. 亚适低温对生殖期草莓叶片结构和光合荧光特性的影响[J]. 中国农业科技导报, 2025, 27(10): 51-62.

Figures/Tables 9

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品种 Variety	处理Treatment	胁迫时间 Stress time/d	叶面积 LS/cm²	叶厚度 LT/mm	叶体积 LV/cm³	叶组织密度 LTD/（g·cm^-3）	比叶面积 SLA/（cm²·g^-1）	叶干物质含量 LDMC/（g·g^-1）
宁玉Ningyu	CK	0	32.23±3.25 a	0.44±0.03 a	1.43±0.20 a	0.15±0.03 c	157.36±29.04 abc	0.28±0.04 b
		7	27.85±4.45 b	0.35±0.04 b	0.99±0.22 b	0.17±0.02 b	170.32±32.01 a	0.24±0.03 c
		14	28.44±3.43 b	0.29±0.02 c	0.81±0.14 c	0.24±0.02 a	148.49±10.80 bc	0.29±0.01 ab
	LT	0	32.23±3.25 a	0.44±0.03 a	1.43±0.20 a	0.15±0.03 c	157.36±29.04 abc	0.28±0.04 b
		7	27.38±2.78 b	0.37±0.04 b	1.01±0.20 b	0.16±0.02 bc	168.85±16.61 ab	0.25±0.02 c
		14	26.09±1.43 b	0.29±0.03 c	0.75±0.10 c	0.25±0.02 a	141.49±8.48 c	0.30±0.03 a
京藏香 Jingzangxiang	CK	0	18.45±6.28 b	0.34±0.03 a	0.63±0.23 b	0.40±0.67 a	143.34±49.85 b	0.35±0.21 a
		7	20.75±2.47 b	0.30±0.04 b	0.64±0.14 b	0.21±0.05 a	160.86±32.59 ab	0.26±0.05 ab
		14	25.04±3.85 a	0.27±0.03 c	0.68±0.16 ab	0.25±0.04 a	149.67±13.02 b	0.31±0.01 ab
	LT	0	18.45±6.28 b	0.34±0.03 a	0.63±0.23 b	0.40±0.67 a	143.34±49.85 b	0.35±0.21 a
		7	21.81±2.44 ab	0.32±0.03 ab	0.70±0.13 ab	0.18±0.03 a	180.97±25.16 a	0.23±0.02 b
		14	25.28±4.18 a	0.32±0.04 ab	0.81±0.18 a	0.24±0.04 a	137.31±17.36 b	0.32±0.03 ab

品种 Variety	处理Treatment	胁迫时间 Stress time/d	叶面积 LS/cm²	叶厚度 LT/mm	叶体积 LV/cm³	叶组织密度 LTD/（g·cm^-3）	比叶面积 SLA/（cm²·g^-1）	叶干物质含量 LDMC/（g·g^-1）
宁玉Ningyu	CK	0	32.23±3.25 a	0.44±0.03 a	1.43±0.20 a	0.15±0.03 c	157.36±29.04 abc	0.28±0.04 b
		7	27.85±4.45 b	0.35±0.04 b	0.99±0.22 b	0.17±0.02 b	170.32±32.01 a	0.24±0.03 c
		14	28.44±3.43 b	0.29±0.02 c	0.81±0.14 c	0.24±0.02 a	148.49±10.80 bc	0.29±0.01 ab
	LT	0	32.23±3.25 a	0.44±0.03 a	1.43±0.20 a	0.15±0.03 c	157.36±29.04 abc	0.28±0.04 b
		7	27.38±2.78 b	0.37±0.04 b	1.01±0.20 b	0.16±0.02 bc	168.85±16.61 ab	0.25±0.02 c
		14	26.09±1.43 b	0.29±0.03 c	0.75±0.10 c	0.25±0.02 a	141.49±8.48 c	0.30±0.03 a
京藏香 Jingzangxiang	CK	0	18.45±6.28 b	0.34±0.03 a	0.63±0.23 b	0.40±0.67 a	143.34±49.85 b	0.35±0.21 a
		7	20.75±2.47 b	0.30±0.04 b	0.64±0.14 b	0.21±0.05 a	160.86±32.59 ab	0.26±0.05 ab
		14	25.04±3.85 a	0.27±0.03 c	0.68±0.16 ab	0.25±0.04 a	149.67±13.02 b	0.31±0.01 ab
	LT	0	18.45±6.28 b	0.34±0.03 a	0.63±0.23 b	0.40±0.67 a	143.34±49.85 b	0.35±0.21 a
		7	21.81±2.44 ab	0.32±0.03 ab	0.70±0.13 ab	0.18±0.03 a	180.97±25.16 a	0.23±0.02 b
		14	25.28±4.18 a	0.32±0.04 ab	0.81±0.18 a	0.24±0.04 a	137.31±17.36 b	0.32±0.03 ab

品种 Variety	处理 Treatment	胁迫时间 Stress time/d	叶绿素a Chl a/（mg·g^-1）	叶绿素b Chl b/（mg·g^-1）
宁玉Ningyu	CK	0	2.33±0.04 a	1.32±0.02 a
		7	2.29±0.11 a	1.29±0.14 a
		14	2.28±0.08 a	1.24±0.07 a
	LT	0	2.33±0.04 a	1.32±0.02 a
		7	2.24±0.03 a	1.23±0.06 a
		14	2.28±0.06 a	1.23±0.05 a
京藏香 Jingzangxiang	CK	0	2.11±0.01 b	1.13±0.04 ab
		7	2.14±0.02 ab	1.09±0.02 b
		14	2.15±0.04 ab	1.16±0.02 a
	LT	0	2.11±0.01 b	1.13±0.04 ab
		7	2.14±0.04 ab	1.10±0.01 b
		14	2.18±0.03 a	1.15±0.00 a

品种 Variety	处理 Treatment	胁迫时间 Stress time/d	叶绿素a Chl a/（mg·g^-1）	叶绿素b Chl b/（mg·g^-1）
宁玉Ningyu	CK	0	2.33±0.04 a	1.32±0.02 a
		7	2.29±0.11 a	1.29±0.14 a
		14	2.28±0.08 a	1.24±0.07 a
	LT	0	2.33±0.04 a	1.32±0.02 a
		7	2.24±0.03 a	1.23±0.06 a
		14	2.28±0.06 a	1.23±0.05 a
京藏香 Jingzangxiang	CK	0	2.11±0.01 b	1.13±0.04 ab
		7	2.14±0.02 ab	1.09±0.02 b
		14	2.15±0.04 ab	1.16±0.02 a
	LT	0	2.11±0.01 b	1.13±0.04 ab
		7	2.14±0.04 ab	1.10±0.01 b
		14	2.18±0.03 a	1.15±0.00 a

品种 Variety	处理Treatment	胁迫时间 Stress time/d	净光合速率P_n/ （μmol·m^-2·s^-1）	胞间CO₂浓度C_i/ （μmol·mol^-1）	气孔导度G_s/ （mol·m^-2·s^-1）	蒸腾速率T_r/ （mmol·m^-2·s^-1）	水分利用效率WUE/（mmol·mol^-1）
宁玉Ningyu	CK	0	10.13±1.17 b	333.03±23.76 b	0.15±0.03 b	3.53±1.32 a	3.18±1.32 c
		7	10.52±0.39 b	367.27±3.66 b	0.17±0.01 b	3.03±0.20 ab	3.47±0.11 bc
		14	9.40±0.22 b	334.56±17.02 b	0.12±0.01 b	1.62±0.08 b	5.83±0.42 a
	LT	0	10.13±1.17 b	333.03±23.76 b	0.15±0.03 b	3.53±1.32 a	3.18±1.32 c
		7	12.00±0.49 a	452.21±26.03 a	0.29±0.03 a	4.41±0.51 a	2.74±0.22 c
		14	9.30±0.05 b	357.05±25.40 b	0.15±0.03 b	1.93±0.34 b	4.93±0.92 ab
京藏香 Jingzangxiang	CK	0	9.71±0.61 ab	317.06±27.14 cd	0.12±0.03 b	2.99±0.64 a	3.32±0.53 b
		7	9.26±0.35 ab	361.21±19.05 b	0.14±0.03 b	1.92±0.26 b	4.88±0.52 a
		14	9.85±0.12 a	306.95±7.69 d	0.12±0.00 b	1.98±0.10 b	4.98±0.24 a
	LT	0	9.71±0.61 ab	317.06±27.14 cd	0.12±0.03 b	2.99±0.64 a	3.32±0.53 b
		7	9.59±0.38 ab	401.51±6.07 a	0.22±0.05 a	3.46±0.52 a	2.80±0.29 b
		14	8.79±0.87 b	348.13±28.11 bc	0.09±0.03 b	1.82±0.42 b	4.94±0.89 a