摘要
【目的】研究乙烯利过度刺激采胶所诱导的橡胶树死皮发生、发展过程中的胶乳产量和生理变化规律,为利用乙烯利刺激增产以及采取有效措施预防死皮发生提供理论依据。【方法】选择橡胶树品种‘热研7-33-97’健康植株,通过乙烯利过度刺激采胶诱发不同等级死皮,测定分析不同等级死皮植株胶乳产量和相关生理指标的变化规律,包括pH值、黄色体破裂指数、干胶含量、总固形物含量、硫醇含量、无机磷含量、橡胶粒子粒径分布及平均粒径等。【结果】1)在乙烯利过度刺激采胶过程中,胶乳产量呈先升后降的变化趋势。在刺激割胶早期阶段,胶乳产量不断增加,普遍增产3倍以上,但很快会诱发死皮。随着死皮发生、发展,胶乳产量逐渐下降,最终低于健康植株。2)黄色体破裂会导致乳管堵塞,黄色体破裂指数随植株死皮等级提高而显著提高,这与死皮发生有直接关系。死皮植株的胶乳pH值也略有上升,但仅3级死皮植株与健康植株具有显著差异。3)乙烯利过度刺激对胶乳具有稀释效应,死皮植株胶乳干胶和总固形物含量均低于健康植株,其中2~3级死皮植株中的含量递减,而4~5级死皮植株中的含量逐步回升。4)2~3级死皮植株的胶乳硫醇含量递增,均显著高于健康植株,而4~5级死皮植株中的含量逐步回落,与健康植株无明显差异。2~5级死皮植株的胶乳无机磷含量呈递减趋势,但均高于健康植株。5)健康植株的胶乳橡胶粒子粒径在0.09~2.27μm范围呈单峰分布。随植株死皮发生发展,胶乳橡胶粒子粒径分布向小粒径方向逐步偏移,且峰值逐渐下降。与之相符,胶乳橡胶粒子平均粒径亦随死皮等级提高而逐渐变小,2~5级死皮植株的平均粒径均显著低于健康植株。健康植株的胶乳橡胶粒子平均粒径为0.89μm,而5级死皮植株的平均粒径仅0.79μm。【结论】乙烯利过度刺激采胶会促使胶乳黄色体破裂增加、硫醇和无机磷大量外排、橡胶粒子变小,从而导致乳管系统受损与堵塞,影响橡胶生物合成和胶乳外排,表现出死皮症状。天然橡胶生产中应合理使用乙烯利刺激,避免因过度刺激诱发死皮造成减产。
【Objective】This study aims to investigate the variation patterns of latex yield and physiology during the occurrence and development of tapping panel dryness(TPD)induced by ethephon overstimulation in rubber tree(Hevea brasiliensis),so as to provide a theoretical basis for making better use of ethephon to stimulate latex production and taking effective measures to prevent the occurrence of TPD.【Method】In this study,the healthy plants of rubber tree clone‘Reyan 7-33-97’were used to induce different grades of TPD by overstimulation of tapping with ethephon,and the change patterns of latex yield and related physiological indexes of plants with different grades of TPD were compared and analyzed,including pH,lutoid bursting index,dry rubber content,total solid content,thiol content,inorganic phosphorus content,the size distribution and average size of rubber particles.【Result】1)During tapping with ethephon overstimulation,the latex yield showed a trend of rising first and then falling.The yield increased continuously by more than three fold in the early stage.However,the TPD was soon induced.With the occurrence and development of TPD,the latex yield decreased gradually and finally became lower than that of healthy plants.2)The lutoid bursting index increased significantly with the severity of TPD,the ruptured lutoid then resulted in blockage of the laticifers.This phenomenon was directly related to the occurrence of TPD.The latex pH values of TPD plants also increased slightly,but only the pH value of grade 3 TPD plants showed a significant difference from that of healthy ones.3)Ethephon overstimulation had a dilution effect on latex.The contents of latex dry rubber and total solid in latex of TPD plants were lower than those of healthy ones.The contents decreased gradually in grades 2-3 TPD plants,and then recovered gradually in grades 4-5 TPD plants.4)The thiol contents were significantly increased in grades 2-3 TPD plants,but gradually decreased to nearly normal levels in grades 4-5 TPD plants.In grades 2-5 TPD plants,the inorganic phosphorus contents showed a decreasing trend,but all showed higher than the healthy plants.5)The size distribution of latex rubber particles of healthy plants ranged from 0.09 to 2.27μm with a single peak.With the occurrence and development of TPD,the size distribution gradually moved to the direction of small size,and the peak value also decreased.Consistent with that,the average size of rubber particles became smaller with the increase of TPD grade.The average particle sizes of grades 2-5 TPD plants were significantly lower than that of healthy ones.The average particle size of healthy plants was 0.89μm,while that of grade 5 TPD plants was only 0.79μm.【Conclusion】Over stimulation of tapping with ethephon will result in an increase in the burst of lutoid,outflow of a large amount of thiol and inorganic phosphorus,and the decrease of rubber particles,which will lead to the damage and blockage of the laticifer system,affect the rubber biosynthesis and latex flow,and finally show the symptoms of TPD.In the production of natural rubber,ethephon stimulation should be reasonably used,avoiding excessive stimulation to induce TPD which always results in yield reduction.
作者
刘辉
胡义钰
冯成天
袁坤
王真辉
Liu Hui;Hu Yiyu;Feng Chengtian;Yuan Kun;Wang Zhenhui(Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture and Rural Affairs State Key Laboratory Incubation Base for Cultivation & Physiology of Tropical Crops Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences ,Haikou 571101)
出处
《林业科学》
EI
CAS
CSCD
北大核心
2021年第6期46-55,共10页
Scientia Silvae Sinicae
基金
海南省自然科学基金项目(319QN320)
中国热带农业科学院基本科研业务费专项资金(1630022019012)
现代农业产业技术体系建设专项资金(CARS-33-ZP1)。
关键词
橡胶树
死皮
生理效应
乙烯利刺激
胶乳
Hevea brasiliensis
tapping panel dryness
physiological effect
ethephon stimulation
latex