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1.
J. Kocielniak 《Journal of Agronomy and Crop Science》1993,171(2):73-81
Night chilling (5 °C) subsequently lowered photosynthetic intensity in the leaves of maize seedlings at 20 °C through an increase in leaf diffusive resistance brought on by lower tissue water content in morning hours. A more significant increase in leaf diffusion resistance was observed when soil temperature was lowered than in the case of lower air temperature.
The unfavorable effect of soil and air cooling temperature on photosynthesis was limited by air saturated with water vapour. However, as a result of lowering the night temperature from 5 °C to 1 °C, the efficiency of the protective influence of higher atmospheric humidity was decreased. This demonstrates that the participation of factors unrelated to plant water status in inhibiting photosynthesis increases with lower night temperatures.
An additional reason for inhibited photosynthesis following cool nights was a decrease in chlorophyll accumulation, below 50 μg per 1 cm2 of leaf area. 相似文献
The unfavorable effect of soil and air cooling temperature on photosynthesis was limited by air saturated with water vapour. However, as a result of lowering the night temperature from 5 °C to 1 °C, the efficiency of the protective influence of higher atmospheric humidity was decreased. This demonstrates that the participation of factors unrelated to plant water status in inhibiting photosynthesis increases with lower night temperatures.
An additional reason for inhibited photosynthesis following cool nights was a decrease in chlorophyll accumulation, below 50 μg per 1 cm
2.
鲁西南地区果树需冷量的研究 总被引:2,自引:0,他引:2
2000~2001年,采用Utah加权模型,先后对鲁西南地区常见的葡萄、桃和油桃、杏品种的需冷量进行了研究。结果表明:不同树种、品种的需冷量差异显著。葡萄的需冷量最高,为1010~1840c.u。桃和油桃最低,花芽为620~910c.u,叶芽为500~890c.u。杏介于二者之间,花芽和叶芽均为790~910c.u。各树种、品种的需冷量年际间均有差异。葡葡、杏不同品种需冷量的高低与本品种果实成熟期早晚的关系表现为成熟期早,需冷量低;成熟期晚,需冷量高。但桃树不同品种的需冷量高低与本品种的果实成熟期无明显相关关系,果实成熟期早,但需冷量较高的情况普遍存在。同一品种其花芽、叶芽的需冷量不一,基本趋势是花芽的需冷量高于叶芽。 相似文献
3.
The effect of 0, 0.05 or 0.1 mm abscisic acid treatment on chilling tolerance and salicylic acid‐related responses was investigated in young maize seedlings (Zea mays L., hybrid Norma). Although the pre‐treatment of maize seedlings with abscisic acid slightly decreased the chlorophyll content, it also reduced the level of chilling injury caused by 6 days of cold treatment at 5 °C. Under normal growth conditions, increased levels of bound salicylic acid and of bound ortho‐hydroxycinnamic acid were observed in the leaves during abscisic acid treatment. In the roots, abscisic acid did not affect the free and bound salicylic acid levels, but increased the amount of free and bound ortho‐hydroxycinnamic acid. The activity of glutathione‐S‐transferase increased on the 3rd day of abscisic acid treatment, whereas it did not change when followed by cold stress, compared with the control leaves. In the roots, the activities of glutathione reductase, glutathione‐S‐transferase and ascorbate peroxidase increased during the abscisic acid treatment, and those of glutathione‐S‐transferase and ascorbate peroxidase were also stimulated when abscisic acid pre‐treatment was followed by cold stress, compared with the control roots. Our results suggest that an overlap may exist between the abscisic acid‐induced cold acclimation and the salicylic acid‐related stress response. 相似文献
4.
不同品种桃果冷链物流特性差异性研究 总被引:1,自引:0,他引:1
为了探讨不同品种桃果冷链物流特性的差异化问题,从而为其贮运技术的优化提供参考依据,分别以采自山东省蒙阴县岱崮镇的‘仓方早生’、‘春美’、‘中油4号’和‘锦香’黄桃果实为试材,对不同品种桃果实在长途(山东蒙阴至新加坡)冷链物流期间的预冷特性、蓄冷特性、货架期及其品质的变化情况进行了观察,并对其果心温度在冷链物流期间的变化情况进行了全程跟踪检测。结果表明:在整个冷链物流期间,‘中油4号’和‘春美’的果心温度一直低于其余2个品种,说明其均有较好的预冷和蓄冷性能;在山东冷库温度设为0℃、预冷40 h的条件下,不同品种桃果果心温度方能降低至2.5~3.0℃,说明产区桃果贮运企业的冷库制冷能力还有待提高,或需配置专门的预冷设备和优化预冷技术;货架期第2天(到达目的地后),4个品种桃果果肉组织的硬度均在2 kg·cm-2以上;其中‘仓方早生’和‘锦香’果实中可溶性固形物的含量略高于10%,其余品种的均为8%~9%,说明产地采收果实的品质有待提高;不同品种对冷害的敏感性存在一定的差异性。文中综合分析认为:‘中油4号’的贮运品质较好,其预冷和蓄冷性能均佳,其果实外观和肉质均好,且汁液多,味较甜;而其他品种桃果运至目的地后均发生了不同程度的冷害现象。据此,文末提出了采取终端冷链措施以避免冷害发生的建议。 相似文献
5.
É. Darkó J. Fodor S. Dulai H. Ambrus A. Szenzenstein Z. Király B. Barnabás 《Journal of Agronomy and Crop Science》2011,197(6):454-465
To improve the abiotic stress tolerance of maize (Zea mays L.), doubled haploid (DH) plants were produced by in vitro selection of microspores exposed to tert‐butyl hydroperoxide (t‐BuOOH) as a powerful prooxidant This study investigated the tolerance of the progenies of t‐BuOOH‐selected DH lines to oxidative stress, cold and drought in controlled environment pot experiments by analyses of photosynthetic electron transport and CO2 assimilation processes, chlorophyll bleaching and lipid peroxidation of leaves. Our results demonstrated that the t‐BuOOH‐selected DH plants exhibited enhanced tolerance not only to oxidative stress‐induced by t‐BuOOH but also to cold and drought stresses. In addition, they showed elevated activities of antioxidant enzymes such as superoxide dismutase, ascorbate peroxidase, catalase, glutathione reductase and glutathione S‐transferase when compared with the DH lines derived from microspores that were not exposed to t‐BuOOH and to the original hybrid plants. The results suggest that the simultaneous up‐regulation of several antioxidant enzymes may contribute to the oxidative and cold stress tolerance of the t‐BuOOH‐selected DH lines, and that the in vitro microspore selection represents a potential way to improve abiotic stress tolerance in maize. 相似文献
6.
为了缓解水蜜桃果实采后冷藏保鲜对果实品质的负面影响,达到更好的保鲜效果,以江苏省张家港市的凤凰水蜜桃(Prunus persica)为实验材料,研究了不同剂量(0.5kJ/m2、1kJ/m2、1.5kJ/m2)UV-C对低温(3℃?℃)条件下水蜜桃果实冷害和品质的影响。实验结果表明:三种剂量的UV-C处理对水蜜桃均能有效减少果实的褐变,保存果实的可溶性固形物(TSS),并明显延缓了丙二醛(MDA)、多酚氧化酶(PPO酶)的上升趋势;处理之间没有明显的效果差异,但1.5 kJ/m2处理的硬度值在5-20d之间均显著大于CK组(P<0.05),表现出更好的抗软化能力;另外,UV-C处理易使果实相对电导率加速升高,该趋势随照射剂量的增大而增强。 相似文献
7.
8.
为明确热水处理减轻西葫芦果实冷害的最佳处理条件,以“绿丰”西葫芦为材料,电解质外渗率y为冷害的表征指标,在单因素试验基础上,采用二次正交旋转组合试验设计,研究热处理温度x1、热处理时间x2对西葫芦果实表征函数影响,并经统计分析,建立数学模型。 结果表明,所得回归方程为y= 142.608 647-0.690 821x2 + 0.051 444 x12 + 0.007 499 x22,达到极显著水平,且无失拟因素存在;在热处理(43.3℃、28.4 min)的最佳工艺条件下,于(4±0.5)℃低温下胁迫10 d后西葫芦果实电解质外渗率实测值为33.41%,与理论值相对误差为0.95%,较未处理组降低了27.26%。该试验优化西葫芦果实冷害减轻的热处理工艺参数准确可靠、稳定、可行,为西葫芦采后贮藏技术与果蔬冷害防治的进一步研究提供了一定的技术依据。 相似文献
9.
10.