Structural and functional state of the leaves of the blackberry (RUBUS L.) new cultivars in the conditions of the Ukraine’s Lisosteppe

Анотація

The authors present the results of researching the complex of the physiological indices of 25 blackberry cultivars plants leaves, namely Adriene, Apache, Asterina, Black Butte, Black Diamond, Black Magic, Black Pearl, Brzezina, Cacanska Вestrna, Chester, Chief Joseph, Heaven Can Wait, Jumbo, Karaka Black, Kiowa, Loch Tay, Natches, Navaho, Orkan, Ouachita, Reuben, Tornfree, Triple Crown, Nasoloda and Sadove chudo. The direct correlation dependence between the specific surface density of the leaves which characterizes the plants photosynthetic apparatus activity.   The purpose of the investigation was to establish the structural and functional state of the blackberry leaf apparatus which correlate with the plants productivity that would make it possible to estimate the adaptive potential of the cultivars studied. The experiments were conducted on the basis  of the Institute of Horticulture of NAAS of Ukraine (Kyiv) during  20146 – 2017. The object were cultivars enumerated above. The plants had been planted according to the methods of the collectonal strain investigation in the autumn of 2014. The planting plan was 3,00 × 1,25 m. the agrotechnical measures were carried out in conformity with the accepted technology of the small fruit crops cultivation.  The laboratory researches were conducted in the laboratory of the Plants Physiology and Microbiology of Institute of Horticulture of NAAS of Ukraine. The chlorophyll a concentration in the blackberry plants leaves is 1.10–3.10 mg/g of the raw weight. The cultivars Chester, Sadove chudo, Adriene and Apache
had maximum concentration of chlorophyll a (3.10 mg/ g, 2.84 mg/ g, 2.61 mg/g and 2.27 mg/ g respectively) while Brzezina, Black Magic, Black Butte Blackberry and Cacanska Bestrna were characterized by lower indicators (1.46 mg/ g, 1.43 mg/ g, 1.12 mg/ g and 1.10 mg/ g). The chlorophyll b amount hesitated from 0.39 mg/ g (cultivar Cacanska Bestrna) to 1.08 mg/ g (Chester). The chlorophyll a + b sum varied from 1.56 mg/ g (Black Butte) to 4.18 mg/ g of the raw mass (Chester). The photosynthetic process efficiency depended to a certain degree both on the chlorophylls quantitative content in the leaves and on the chlorophylls forms correlation. The more chlorophyll b amount was, the higher potential of the plant adaptability to the reduce of the enlightenment intensity and more stable the pigment system were. It was cultivars Loch Tay and Asterina that were characterized by the lowest chlorophylls a + b correlation and best adaptability to the environment. In their leaves the chlorophyll a amount was more than that of the chlorophyll b  only by 2.1 – 2.2 times. The highest correlation of the both chlorophylls was fixed by Kiowa and Apache (3.2 and 3.4) that proves the lower adaptive properties of those cultivars under the given conditions. The plants with the more active photosynthetic apparatus activity under the optimum conditions accumulated a greater amount of the dry substance per a leaf surface unit. It was the cultivars Natches, Tornfree and Heaven Can Wait that distinguished themselves for the highest indicator of the specific surface density of the leaves (10.8 g/ sm2 , 10.6 and 10.5 g/ sm2 respectively) whereas Navaho, Sadove chudo, Reuben and Adriene for the lowest one (7.1 g/ sm2, 7.5 and 7.7 g/ sm2 each respectively). The researches showed that cultivars Asterina and Loch Tay possessed the highest potential of the adaptability to the enlightenment intensity reduction, the stablest pigment system among the investigated cultivars and the least chlorophylls a + b correlation, whiles Kiowa and Apache had their least correlation – 3.2 and  3.4 respectively.
According to the correlation analysis of the researches data there exists direct dependence ( r = 0.70) between the specific surface density of the leaves, on the one hand, and cultivars productivity, on the other hand. The greatest dry substance number per leaf surface unit was fixed by Natches (10.8 g/ sm2), Tornfree (10.6 g/ sm2) and Heaven Can Wait (10.5 g/ sm2). Thus those cultivars distinguish themselves for higher photosynthetic activity that  ensures the higher yield.