不同耕作方式对苦荞衰老和籽粒灌浆特性的影响

为明确耕作方式对苦荞籽粒灌浆特性及衰老进程变化特征的影响,以苦荞品种黔苦5号为试验材料,设置了免耕、常耕、深耕3种耕作处理,研究了其对苦荞籽粒灌浆动态、根系形态生理、叶片中光合色素含量、抗氧化酶活性和丙二醛(MDA)含量、农艺性状及产量形成指标的影响。结果表明:3种耕作方式下苦荞籽粒灌浆的形态参数(N值)均小于1,耕作方式间差异不明显;灌浆起始势(R₀)、最大灌浆速率(G_max)、灌浆速率为最大时的生长量(W_max._G)均以深耕处理最大,免耕处理最小;不同耕作方式间的最大灌浆速率下的生长量与籽粒生长终值量比值(I)差异较小。深耕处理能促进苦荞根系的生长,且随生育期的推进,根系总长度、根系表面积、根系体积和根系平均直径均呈现单峰曲线的变化趋势,均在灌浆期达最大;深耕处理的根系活力在各时期均高于常耕和免耕处理;随生育期的推进,苦荞叶片中的光合色素含量、超氧化物歧化酶(SOD)及过氧化物酶(POD)活性表现为先增加后降低,耕作方式间以深耕处理最大;MDA含量随生育期的推进则表现为持续增加的趋势,以免耕处理最大,深耕处理最小;深耕处理能显著提高苦荞的农艺性状及产量。综上,深耕处理能促进苦荞籽粒的灌浆,延缓衰老,提高产量,实现增收。

Effect of different tillage methods on senescence and grain filling characteristics of tartary buckwheat

In order to clarify the effects of tillage methods on grain filling characteristics and senescence process of tartary buckwheat, three tillage treatments, namely, no-tillage, constant tillage and deep tillage, were set up with Qianyu No.5, a tartary buckwheat variety, as the experimental material. The effects on grain filling dynamics, root morphology and physiology, photosynthetic pigment content in leaves, antioxidant enzyme activity and malondialdehyde (MDA) content, agronomic characters and yield formation indexes of tartary buckwheat were studied. The results showed that the morphological parameters (N value) of the three tillage methods were all less than 1, and there was no significant difference among the three tillage methods, and when the initial potential of filling (R₀) and the maximum filling rate of (G_max) were maximum, the grain filling rate of the three tillage methods was less than 1. The growth increment (W_{max. G}) was the largest and no-tillage treatment was the least. The difference between the increment of the maximum grouting rate and the final value of grain growth (I) between different tillage methods was small. The deep-tillage treatment can promote the root growth of tartary buckwheat, and the total length, the surface area, the volume and the average diameter of the root system all showed the change tendency of the single-peak curve along with the advance of the growth period and the maximum in the grouting period. The root activity of the deep-tillage treatment was higher than the normal tillage and no-tillage treatment in all periods, and the photosynthetic pigment content, the superoxide dismutase (SOD) and the peroxidase (POD) in the tartary buckwheat leaves were increased with the development of the growth period. The activity increased firstly and then decreased, and the treatment of deep tillage was the highest among tillage methods, while the content of MDA increased continuously with the advance of growing period, with the maximum in the no-tillage treatment and the minimum in the deep tillage treatment. Deep tillage treatment can significantly improve the agronomic characters and yield of tartary buckwheat. In all, deep tillage can promote grain filling of tartary buckwheat, delay senescence, increase yield and income.