Gas exchange and yield of grafted yellow passion fruit under salt stress and plastic mulching

ABSTRACT Irrigation with saline water is one of the main factors that limit gas exchange and yield of yellow passion fruit in the semi-arid region of Brazil. The use of wild species of Passiflora ssp. tolerant to salinity as a rootstock and the application of mulching with plastic film can attenuate the effects of salt stress. The objective of present study was to evaluate the application of plastic film mulching and irrigation with saline water on the gas exchange and yield of yellow passion fruit grafted on P. cincinnata. The experiment was carried out under field conditions, from September 2019 to February 2021, in a 2 × (2 × 2) factorial scheme, in randomized blocks, in split plots and four replications. The treatments were related to irrigation with low-salinity (0.5 dS m-1) and high-salinity (4.5 dS m-1) water in yellow passion fruit plants, accession ‘Guinezinho’, propagated by seed and grafted on Passiflora cincinnata in the soil without and with plastic mulching. Irrigation with 4.5 dS m-1 water reduced gas exchange and yield of yellow passion fruit, but did not affect plants in the plastic mulched soil. Yellow passion fruit grafted on P. cincinnata showed increases in CO2 assimilation rate, but it was not reflected in fruit yield. For cultivation under high salinity conditions (4.5 dS m-1), it is recommended to use yellow passion fruit propagated by seeds in the soil with plastic film mulching.

摘要：在巴西半干旱地区，咸水灌溉是限制黄色西番莲气体交换与产量的主要因素之一。以耐盐野生西番莲属（Passiflora ssp.）物种作为砧木并结合塑料地膜覆盖栽培，可缓解盐胁迫带来的负面影响。本研究旨在探究塑料地膜覆盖与咸水灌溉对嫁接于尖叶西番莲（P. cincinnata）的黄色西番莲气体交换与产量的影响。本试验于2019年9月至2021年2月在大田环境下开展，采用2×(2×2)因子试验设计，随机区组裂区安排，设置4次重复。试验处理为：以‘Guinezinho’黄色西番莲种质为材料，经种子繁殖并嫁接于尖叶西番莲，分别在无地膜覆盖与地膜覆盖的土壤中，采用低盐（0.5 dS·m⁻¹）与高盐（4.5 dS·m⁻¹）水进行灌溉。采用4.5 dS·m⁻¹的咸水灌溉会降低黄色西番莲的气体交换能力与产量，但对地膜覆盖土壤中的植株无显著影响。嫁接于尖叶西番莲的黄色西番莲虽可提升二氧化碳同化速率，但该优势未体现在果实产量上。在高盐（4.5 dS·m⁻¹）环境下开展栽培时，推荐采用种子繁殖的黄色西番莲并配合塑料地膜覆盖栽培。